1 OO

o

COLLOIDS

N HEALTH AND
DISEASE

THE USE OF COLLOIDS

IN

HEALTH AND DISEASE

THE CHADWICK LIBRARY

THE

USE OF COLLOIDS IN
HEALTH AND DISEASE

BY

ALFRED B. SEARLE

WITH FOREWORD

BY

SIR MALCOLM MORRIS

LONDON
CONSTABLE & COMPANY LTD

10 ORANGE STREET, LEICESTER SQUARE, W.C
1920

All rights reserved

Printed in Great Britain

FOREWORD

BY SIR MALCOLM MORRIS, K.C.V.O.

THE subject with which this book is concerned is one
of vast extent and enormous importance. It covers
wide tracts of territory in physiology and medicine.
" All life processes," as Prof. Wolfgang Ostwald has
summarily said, " take place in a colloidal system,"
and that is true both of the normal fluids and secretions
of the organism and of the bacterial toxins, as well as,
in large measure, of the reactions which confer im-
munity. If this is so, it would seem to be an obvious
desideratum that the drugs employed to combat disease
should be in the colloidal state, i.e. in a form in which
they may be isomorphic and isotonic with the elements
of the body. Only so can they be expected to exert
their full potency. The task of thus bringing their
remedial virtue to its highest point is not an easy
one, for colloidal substances, unless prepared with
consummate skill and meticulous care, lack stability,
and are prone to precipitation when brought into
contact with the electrolytes normally present in the
body tissues and fluids. That it is not beyond the
resources of scientific chemistry is clearly shown in
this book. A measure of success has, in fact, been
achieved which leaves no doubt of the brilliant future
which lies before drugs in the colloidal form.
To the study of colloids, both in health and disease,

vi AUTHOR'S NOTE

some of the world's greatest investigators have devoted
and are devoting their genius for research. Much that
was mystery has already been elucidated. A very
considerable body of literature has accumulated, and
the time is ripe for such lucid expositions of ascer-
tained results as will be found in these pages, written
by an acknowledged master of the subject.

AUTHOR'S NOTE

THE present volume is based on a lecture delivered at
the request of the Chadwick Trustees, under the chair-
manship of Sir William Collins, K.C.V.O., and forms one
of a series of works published under their auspices.
Some of the information also appears in the author's
contribution to the British Association Report on
Colloids, viz. The Administration of Colloids in Disease,
published by the Department of Scientific and Indus-
trial Research, and obtainable from H.M. Stationery

Office.

A. B. SEARLE.

THE WHITE BUILDING,
SHKFFIKLD,

November, 1919.

CONTENTS

FOREWORD .........

AUTHOR'S NOTE ........

I. NATURE AND PROPERTIES OF COLLOIDS — AGGLUTINA-
TION— ACTION OF RADIATIONS ON SOLS — COLOUR
OF COLLOIDS .......

II. ANIMAL AND VEGETABLE FLUIDS ....

III. THE HYGIENIC USES OF COLLOIDS — PURIFICATION OF

WATER — SOAPS ......

IV. MICRO-ORGANISMS AND DISEASE — TOXINS AND ANTI-

TOXINS

V. POISONING — DIGESTION AND COLLOIDS .
VI. USE OF COLLOIDS IN MEDICINE ....

VII. PREPARATION OF COLLOIDAL SOLS — ASSAYING COL-
LOIDAL SOLS — THE ULTRA-MICROSCOPE — THE TYN-
DALL PHENOMENON — GOLD NUMBER— STABILITY
NUMBER . .

VIII. COLLOIDS AS GERMICIDES AND DISINFECTANTS

IX. TYPICAL COLLOIDAL REMEDIES AND THEIR USES —
GOLD — SILVER — MERCURY — IRON — ANTIMONY —
MANGANESE — COPPER — PLATINUM — PALLADIUM
OXIDE — PALLADIUM — NICKEL — IODINE — SULPHUR
— ARSENIC — OXIDES — QUININE — COCAINE — COM-
PLEX COLLOIDS ......

X. CONCLUSION .......

INDEX .

PACK
V

vi

I

21
29

36
42

45

53
67

76
108
"3

THE USE OF COLLOIDS IN
HEALTH AND DISEASE

CHAPTER I

NATURE AND PROPERTIES OF COLLOIDS

THE difference between a healthy and a diseased
organism is so important, and the necessity for im-
proving the health of the nation is so urgent, that any
application of knowledge to this end is worth very serious
consideration. Consequently it is necessary that any
possible use of discoveries in branches of science,
other than medicine, should be brought to the atten-
tion of all concerned with the least possible delay.
This application of knowledge gained in various fields
of investigation to the improvement of health and the
reduction of disease was one of the foundation prin-
ciples of Sir Edwin Chadwick, whose generosity made
the present publication possible.

The study of hygiene and of many diseases has been
enormously facilitated by the discovery that many of
the ills that flesh is heir to, and many others which it
is unnecessary to suffer, are due to the influence of
bacteria and their products. There is, however, a
still wider cause of disease, of which bacteria form
only a part, which is due to the peculiar structure of
the essential organs of all animals and vegetables — a.

2 USE OF COLLOIDS IN HEALTH & DISEASE

structure which has long been recognised in certain
ways, though some of its properties have only been
realised within the last decade or two.

We are all aware that living organisms are com-
posed of a number of cells consisting of an external
envelope, or membrane, and an enclosed fluid. Even
the most complex animal structure can be shown to
consist of a vast number of such cells, differing enor-
mously in their shape and functions, but all possessing
certain well-defined characteristics. The membranes
or envelopes of these cells possess the peculiar property
of allowing certain substances to pass through them
quite readily whilst others cannot do so, and on this
property depend many of the most complex functions
of the whole organism. The processes of digestion and
assimilation and the oxygenation of the blood are
well-known examples of the selective passage of certain
substances through the membranes concerned. Some
investigators, including Moore and Roaf,1 do not
accept the idea of membranes of selective permeability,
but consider the phenomena usually attributed to
them as being due to selective absorption. This
appears to be specially applicable to living cells, as
several colloids behave differently in these from what
they do in synthetic, or " dead," membranes.

It is well known that if a mixture of sand, gelatin,
salt, and water were to be filtered through cotton wool,
paper, or other recognised filtering medium, the sand
would remain on the filter, but the salt and gelatin
would pass through in solution in the water. It is not

1 Hober, Arch. ges. Physiol., 1913, 150, 15 ; Moore and Roaf,
Roll. Zeits., 1913, 13, 133,

NATURE AND PROPERTIES OF COLLOIDS 3

so well known that if such a solution of salt and
gelatin is placed in a parchment or collodion cup, and
the latter partially immersed in a vessel of water, the
salt will pass into the water, but the gelatin will
remain behind in the cup. By repeatedly changing
the water in the outer vessel the whole of the salt may
be removed from the gelatin solution. This distinctive
property of salt and gelatin was investigated by
Thomas Graham, who found that all those substances
which pass readily through a filter, but not through a
membrane, had certain other resemblances. He also
found that some substances could exist in such a state
that they would pass either through a membrane or
not, according to their method of preparation. Fara-
day extended this investigation, prepared a number
of substances in this state, and found that they had
properties quite different from those ordinarily pos-
sessed by them. Thus, metallic gold, which is peculiarly
insoluble and resistant, could be obtained in so fine a
state of suspension that it passed readily through all
ordinary filters and behaved as a solution. At the
same time its colour was entirely different from that
characteristic of the metal, being red or blue instead
of yellow, and its other properties were changed to a
correspondingly great extent.

When Thomas Graham, in 1861, found that certain
solutions would pass through a membrane, whilst
others did not do so, he little realised how great a
discovery he had made. He had, in fact, found, and
was able to describe, a state of matter of which little
or nothing was realised at the time, though many
industries, and indeed life itself, were and are dependent

4 USE OF COLLOIDS IN HEALTH & DISEASE

on it. Graham's chief discovery in this connection
was that substances may enter into solution in such
a manner that they exhibit characteristics which are
quite different from those of a true solution. To this
intermediate state he applied the term " colloidal "
(from Kolla=g\ue), as glue, gelatin, and allied sub-
stances were most readily recognised by him as being
in the colloidal state. Since Graham's time it has been
found that most substances can be obtained in the
colloidal state, their occurrence being sometimes due
to reactions which are specially characteristic of
animal or vegetable organisms and sometimes to
purely inorganic changes.

The colloidal state may be defined as a physical
condition of matter consisting of at least two parts or
phases, one of which is the active substance and the
other the one in which it is distributed. The former
is termed the disperse phase ; it is the active agent and
may consist of either solid or liquid particles which are
so minute that they remain for an indefinitely long
period in suspension. The second phase is either a
liquid or an otherwise homogeneous complex material ;
it is known as the dispersion medium. Such a definition
does not, however, give any clue to the peculiar pro-
perties of substances when in the colloidal state, and
it might be applied with accuracy to any turbid fluid.
In a colloidal solution — which not being a true solution
is preferably termed a sol — the dispersed substance is
able to react in a manner quite different from what
would ordinarily be anticipated. The dispersed or
suspended particles are not merely so minute tHat the
effect of gravity on them is counterbalanced by other

NATURE AND PROPERTIES OF COLLOIDS 5

forces which keep them in suspension (though they
are often only one-thousandth part of the size of
average bacteria), but they are in a state of unordered
oscillation which gives rise to the well-known Brownian
movement. They behave in a liquid in a manner very

a. Hydrogen molecules. b. Chloroform molecules.

c. Haemoglobin molecules. d?> £,/,£'• Par tides of colloidal gold.
h (large circle). Particles which precipitate from gold suspensions.

FIG. i. RELATIVE SIZES OF COLLOIDAL PARTICLES AND
MOLECULES

(Scale i : 1,000,000)

similar to the molecules and atoms of a gas, and are in
constant movement, travelling at a high velocity and
repeatedly colliding with each other. There is no
group of substances which are invariably colloids.
Thus soaps dissolve in alcohol and behave as true

6 USE OF COLLOIDS IN HEALTH & DISEASE

crystalloids ; in water they behave equally character-
istically as colloids. Common salt, on the contrary,
behaves as a colloid in relation to benzole, but as a
crystalloid when dissolved in water. Von Weimarn
and others have shown that so many substances can
be obtained in the form of colloidal solutions that it is
probably correct to regard colloids as substances which
are in a particular state rather than as forming a
distinct group of substances. Colloids are readily
divisible into two fairly well-defined groups to which
various names have been given by different investi-
gators, the most generally accepted being emulsoid
(fluid particles) and suspensoid (solid particles), as
suggested by Wo. Ostwald. The colloids in the first
group have many of the properties of gelatin or glue ;
they swell when immersed in a suitable fluid (water),
absorbing a large quantity of it, and gradually become
so dispersed as to possess many of the properties of a
solution. The apparently solid particles have many of
the properties of a liquid, and for this reason the term
emulsoid is very aptly applied to them. The behaviour
of emulsoids towards electrolytes is so complex that
their classification on an adequate, yet simple, scale
is, at present, impossible. The second group of
colloids contains substances which are much more
sensitive to small traces of added substances, and the
electric charge acquired by them is much greater.
They appear to consist of extremely minute particles
of solid matter, though this adjective must not be
applied too rigidly in this connection.

There are many well-known organic substances
which occupy an intermediate position between

NATURE AND PROPERTIES OF COLLOIDS 7

colloids and crystalloids, and are conveniently termed
semi-colloids. Casein, soap, many degradation pro-
ducts of albumen, peptones, and other constituents of
animal organisms, and several dyes belong to this
class. Thus albumen is a true emulsoid, but the pro-
talbic and lysalbic acids derived from it diffuse through
the parchment and behave in other ways as crystal-
loids, whilst at the same time having several properties
(such as opalescence, viscosity, and " protective
action ") which are characteristics of colloids. Semi-
colloids, such as soaps, may not be colloids under
ordinary conditions, but form colloidal sols when in
contact with certain liquids ; they are sometimes
termed colloidogens. Other semi-colloids are clearly
electrolytes, but their boiling points and vapour pres-
sures are approximately the same as those of water ;
these and other properties are so abnormal that such
substances must be classed among the semi-colloids.

Each colloidal particle also carries a characteristic
definite charge of electricity, some colloids being
electro-positive and others electro-negative. Usually,
when any given substance is in the colloidal state it
has the same electric sign, but by adopting special
methods of preparation it is possible to produce some
substances in a colloidal form in which the particles
may have either a positive or a negative electric
charge. The electrification of colloidal particles may
be compared with that of a piece of glass suspended by
a thin silk thread and rubbed with a piece of amal-
gamated silk. If a second piece of glass similarly
electrified by rubbing is brought near to the first there
will be a mutual repulsion. On the other hand, a

8 USE OF COLLOIDS IN HEALTH & DISEASE

piece of ebonite which has been rubbed with fur will
attract the glass because it carries an electric charge
of the opposite sign. The electric charge is not the
total amount of electricity which the body possesses,
but only the excess or deficit of that which it carries
compared with the neutral electrical condition.

It is important to note also that the chemical com-
position, and often the physical appearance of a sub-
stance, gives no indication of the electric charge which
it has acquired, so that unless the charge is definitely
investigated its existence may be overlooked. This has
to a large extent been the case in the study of many
drugs and other remedies.

Substances such as glass and ebonite are most easily
charged electrically as the result of friction, but this
is by no means the only or even the most important
cause of excitation. If two different metals are
moistened and brought into contact, a feeble but observ-
able electrification is produced. This is easily shown
by holding a silver and copper coin edgewise on the
tongue. So long as the coins are separate no electrifica-
tion results, but directly they touch each other at some
point away from the tongue the taste produced by the
electrification becomes apparent. If two dissimilar
metals are partially immersed in a liquid which can
chemically react on one of them, a simple voltaic cell
or battery unit is formed, the electric current pro-
duced depending on the sizes of the pieces of metal
and on the nature of the fluid used. Chemical action
and electric phenomena are, indeed, so closely related
that in many instances one cannot occur without the
other. In fact, many phenomena which are generally

NATURE AND PROPERTIES OF COLLOIDS 9

regarded as chemical are largely electrical in character,
or at least may be helpfully considered as such.

For example, the dissociation of a compound into
its elements or into two distinct groups of ions is
frequently accompanied by the assumption of definite
electric charges by each of the groups. Thus, when a
solution of common salt in water is made sufficiently
dilute, the salt is dissociated into positively charged
sodium and negatively charged chlorine particles, or
ions. Sulphuric acid — a more complex substance
— is dissociated into positive hydrogen ions and
negative SO4 ions. Even a partial dissociation of the
fluid in which the substance is dissolved or suspended
may cause the colloid to acquire an electric charge.
Thus, water (H+-OH~) can form two classes of colloids
the particles of which are respectively positively and
negatively charged, and it is suggested that in many
cases there is a chemical combination with the liquid

aPt+H+-OH- = (Pt.H+)+OH-,
or

aPb+H+'OH- = (Pb,OH-)+H+.

The charge on a sol is very much less than on an
equivalent amount of the corresponding ion, and,
therefore, a larger amount of sol will be required when
it is used as a reagent.

Burton has estimated a charge for a single particle
of gold and silver sols on the assumption that the
amount of Al in aluminium salts which just precipi-
tates the gold or silver has acquired the same amount
of positive electricity as that amount of negative
electricity acquired by the precipitated particles.

The volume of a particle is 2Xio~4 cc., so that

io USE OF COLLOIDS IN HEALTH & DISEASE

100 cc. of a sol with 6-5 mgms. silver contains 3 x io10
particles. This volume of sol required 3-oxio~5
and 2-6xio~5 gms. of A12(SO4)3 for precipitation,
from which the charge on a particle is 2-8xio~2
electrostatic units, and the charge on one gram-equiva-
lent of silver in a sol is 4 per cent of the charge on one
gram-equivalent of silver ion. This dissociation on
solution with the assumption of an electric charge is
well known to chemists, though it is not so obvious
to others on account of the minuteness of the particles
and of the charges which they carry. There is a
general agreement among those who have studied the
subject that colloidal sol particles are enclosed by a
double electric layer, as suggested by Quincke and
Helmholtz ; when a particle is negatively charged
there is a negatively electrified layer on its surface,
whilst in the liquid immediately surrounding the
particle is a corresponding layer which is charged
positively. Burton has shown that there is a layer of
hydroxide, or hydride, on the colloidal metals which
may affect the external change on these sols. It is
not definitely known how this double layer is formed,
and for most purposes it is sufficient to regard the
particles as positively or negatively charged, the
effect of the double layer being neglected.

Any substance which conducts an electric current,
and is decomposed thereby into separate groups of
ions, is known as an electrolyte. The terminals, or
plates, by which the current is passed through a liquid
are known as electrodes, the one by which the current
is supposed to enter being termed the positive (-J-)
electrode, or anode, and the other, the negative (— )

NATURE AND PROPERTIES OF COLLOIDS n

electrode, or kathode. When a current of electricity
is passed through the solution the positively and
negatively charged groups tend to collect at the
opposite ends of the solution, i.e. they tend to travel
to each electrode respectively, and are in this way
separated from each other, though they lose their
characteristic charge as soon as they come into con-
tact with the electrode. Thus, if a current of electricity
is passed through water containing sufficient acid to
render it a conductor, the oxygen atoms will pass to
the anode and the hydrogen to the kathode, each
escaping from the solution in the form of a gas without
any electric charge. Between the electrodes, however,
the oxygen ions have their distinctive charges and are
able thereby to act very differently from the electrically
neutral gases bearing the same names. When a liquid
is contained in a porous vessel or membrane, which is
partially immersed in a second liquid, and a current
is passed from one liquid to the other, the membrane
plays an important part. It prevents the liquids from
mixing rapidly, whilst it allows them to come into
contact with each other, so that by arranging the
electric current to pass in a suitable direction one sub-
stance may be passed through the membrane and thus
separated more rapidly than by the slow process of
unaided dialysis or diffusion, whilst its separation from
other substances in solution is effected more easily
and with less general disturbance than if purely
chemical methods are used. The chief investigations
of the movements of colloidal particles under the in-
fluence of an electric current are based on the work of

12 USE OF COLLOIDS IN HEALTH & DISEASE

Linder and Picton,1 who with other observers have
found that the substances mentioned in Table I
move to either the positive or the negative electrode,
as shown, when suspended in pure water. In dilute
solutions of salts, alkalies, or acids, entirely different
characteristics may be observed with the same colloidal
particles.

Thus, some colloids such as globulin and silicic acid
are negatively charged in alkaline solutions and posi-
tively charged in acid solutions.

TABLE I

ANIONIC

CATHONIC

(negatively charged and mov-
ing to the positive pole)

Antimony sulphide
Arsenic sulphide
Cadmium sulphide
Platinum sol
Silver sol
Gold sol
Mercury sol
Silver chloride
Silver bromide
Silver iodide
Vanadic oxide
Tin oxide
Silica

Aniline blue
Indigo

Molybdene blue
Soluble Prussian blue
Eosin

(positively charged and mov-
ing to the negative pole)

Hydroxides of

Iron, Chromium
Copper, Aluminium
Zirconium, Cerium
Thorium
Bredig sols of

Bismuth, Lead
Iron, Copper
Hoffmann violet
Magdalene red
Methyl violet
Rosaniline hydrochloride
Bismarck brown
Methylene blue
Albumen
Haemoglobin
Agar
Titanic oxide

1 Journ. Chem. Soc., 61, 148 ; 87, 63 ; 71, 568 ; 87, 1906.

NATURE AND PROPERTIES OF COLLOIDS 13

ANIONIC CATHONIC

(negatively charged and mov- (positively charged and mov-

ing to the positive pole) ing to the negative pole)

Fuchsine Diatoms

Iodine Unicellular algae

Sulphur Vegetable organisms

Selenium
Shellac
Resin
Starch
Mastic
Caramel
Lecithin
Chloroform
Oil emulsions
Amoeba? and animal
organisms

The electric charges on gelatin, agar, and silicic acid are
very small and difficult to observe.

The rate of movement of a particle in an electric
field is independent of the size of the particle, but is
affected by the viscosity of the fluid and the potential
of the current.

The employment of electricity remedially for effect-
ing the movement of the colloidal substances in the
living cells is, however, extremely limited, especially
with regard to animal organisms, as a separate elec-
trode would require to be introduced into each indi-
vidual cell — a hopelessly impracticable condition.
The result of applying an electric current to a large
area is entirely different from that which occurs during
the electrolysis of a single cell. When two sols of the
same sign are mixed they not only do not precipitate

14 USE OF COLLOIDS IN HEALTH & DISEASE

each other, but the mixed sol acquires the stability of
the more stable component. No adequate explanation
of this fact has yet been published, though the fact
itself is indisputable. When two particles of opposite
sign come within a suitable distance of each other they
are mutually attracted and, if sufficiently free, will
eventually touch and discharge each other. The
product will then be electrically neutral unless one of
the particles carries a larger charge than the other,
when the product will carry the balance of the charge
or will decompose, forming an electrically neutral
substance — which settles more or less rapidly — and a
negatively charged product.

Substances in the colloidal sol state have correspond-
ing electric charges and therein bear a very close
resemblance to substances which become ionised in
solution. They attract particles of opposite sign and
repel those of like sign which come within the sphere
of their influence, and when two colloidal sol particles
of opposite sign come into contact with each other
they are mutually discharged, and the combined pro-
duct settles more or less rapidly. Thus, the effect of
discharging two colloidal sol particles is to remove
them from the active colloidal state and to form a
precipitate or even a coagulum. This may, under some
conditions, retain a certain amount of chemical
activity, and being then in an intermediate state
between a sol and a precipitate is conveniently known
as a gel. Gels are usually obtained when emulsoid sols
are cooled or evaporated ; they may be regarded as
composed of two liquid phases, whereas a sol bears a
closer resemblance to a solid phase dispersed in a liquid

NATURE AND PROPERTIES OF COLLOIDS 15

one. Gels have characteristic optical properties, such
as double refraction.

Agglutination, or the precipitation of colloids of like
sign, occurs in some cases, e.g. with toxins and bacteria
sols. Though extensively used by some pathologists
as the basis of treatment of diseases due to toxins,
bacteria, etc., the precise nature of the phenomena
which produce agglutination are by no means well
understood. Lottermoser, in 1901, found that when a
positive sol precipitates a negative one, the precipitate
contains both colloids.

The amount of one sol required to precipitate
another varies with the nature of the sols, and the
precipitate contains both colloids, though, owing to
the difficulty of nitration without adsorption, the
liability of the excess of colloid in the sol to precipitate,
and the slowness of the reaction, it is often difficult
to determine the amount of each colloid in a precipitate.

The equivalent amount of sols required to cause
precipitation is not a chemical equivalent, but an
electrical one ; usually the maximum precipitation
occurs when the positive charge on one cell exactly
equals the negative charge on the other, but the
number of particles, their size, and the rate of mixing
affect the results.

Substances in colloidal solution behave quite differ-
ently from those which are merely in suspension.
Thus, coarse suspensions are not affected by electro-
lytes and they do not usually bear a definite electric
charge, whereas colloidal sols — unless protected — are
very sensitive even to traces of electrolytes, and
readily migrate towards one pole when an electric

16 USE OF COLLOIDS IN HEALTH & DISEASE

current is passed through them. It is a mistake to
regard them merely as fine suspensions, as the proper-
ties of a substance undergo considerable change when
it is converted into the sol state. They do not behave
precisely the same as either suspensions or solutions,
but occupy an intermediate position for which the
term " sol " is preferable. It was at one time thought
that colloidal substances could be defined as those
which appeared to be in suspension but do not pass
through a parchment or collodion membrane into an
external volume of water. This is by no means always
the case, as Graham soon found, and since his time
more anomalies have been discovered. It is scarcely
possible, therefore, in simple terms to say precisely
which substances are colloidal and which are not,
though for most practical purposes the distinction is
readily appreciated. Like " life/' we may have a fairly
clear concept, but cannot express it in mere words.

The difficulty of finding a clear line of demarcation
between colloidal and other substances is greatly
intensified when living organisms are studied, as
reactions take place in these which do not occur in the
dead organism. For example, the peptones are a
class of nutritive substances which are in many
respects typically colloidal, and in the laboratory
their solutions do not pass through animal or vegetable
membranes. In the living organism, on the contrary,
peptone solutions pass readily through certain mem-
branes and owe their nutritive power to this property.
Haematin, on the other hand, is a typical crystalloid
substance which might be expected to pass readily
through the blood vessels, yet it does not do so as

NATURE AND PROPERTIES OF COLLOIDS 17

long as the organism is alive. Here are two typical
substances, both acting precisely contrary to the
general behaviour of the groups to which they belong,
whilst in the living organism, but behaving normally
when removed from the organism and studied in vitro.
This difference in behaviour impels all investigators
who are aware of it to pause ere they draw conclusions
from laboratory experiments and apply them to the
living subject. Even in so apparently simple a
phenomenon as the passage of a substance through a
membrane, the effect of "life" may be to upset all
prognostications from the tests on dead or synthetic
materials. This fact needs specially to be borne in
mind when dealing with the introduction of drugs and
other substances into the living subject, or seriously
erroneous conclusions may be drawn.

Turning again to the characteristics of colloidal
substances, it should be observed that they are most
remarkably active, an apparently minute proportion
of a suitable colloid frequently effecting the precipita-
tion of many times its weight of another substance
from " solution." In this respect, many colloids re-
semble enzymes, or so-called vegetable ferments, and
bacteria, though they do not reproduce themselves
like living organisms. They owe their activity to
their minuteness and to the fact that substances when
in the colloidal state have an enormous surface area
as compared with their volume or weight, and as
chemical reactions depend on the amount of contact
between two or more particles these reactions will
proceed the more rapidly and completely when the
substances have a large surface area and are in a state
c

i8 USE OF COLLOIDS IN HEALTH & DISEASE

of oscillation. It is well known that chemical reactions
can only occur when two or more substances are in
direct contact, and as the completeness of the reaction
depends on the amount of contact, colloidal substances
are very powerful because of the enormous area they
possess.

On the other hand, mass plays an important part
in all chemical reactions and largely regulates their
intensity. The mass of colloidal sol particles is so
minute that the objectionable effect of intense reactions
on the human subject are largely avoided, whilst the
advantages of rapid and complete reaction are secured.
For this reason, certain medicines administered in the
colloidal form are not merely more active and possess
greater penetrating power, but they are free from the
poisonous effect of the same substances when given in
the form of tincture or solution. The difference in
behaviour of a solution of iodine in alcohol or aqueous
potassium iodide, when compared with that of colloidal
sol iodine, is most impressive. The forms of iodine
usually employed induce pain and other symptoms of
iodism, whereas large doses of colloidal sol iodine (if
the preparation has been properly prepared) are quite
free from this risk. A colloidal preparation of iodine
in petroleum or other mineral oil can be rubbed into
the skin without leaving any stain, the iodine being
absorbed more readily than the oil. A solution of
commercial iodine in alcohol or in potassium iodide
leaves a characteristic stain when applied to the
skin.

The precise reason for this rapid absorption and
non-staining action has not been definitely ascertained,

NATURE AND PROPERTIES OF COLLOIDS 19

but it has been repeatedly demonstrated in a variety
of cases.

The action of radiations on sols. — The y-rays of
radium and the X-rays have no action on colloidal
sols. The positively charged a-rays of radium have
not sufficient penetrating power for any action they
may have to be important. The /3-rays of radium,
which are negatively charged, hasten the coagulation
of the positively charged particles and increase the
stability of the negatively charged ones. A sample of
haemoglobin was coagulated by the rays in several
hours by Hewin and May en.1 Some albumen sols
when exposed to the ultra-violet light are rapidly
coagulated. These reactions partially explain some of
the remedial effects of various radiations on the human
system. It is clear that such effects are limited by the
permeability of the skin, and that for deep-seated
affections better results may be anticipated from the
introduction of suitably charged particles (colloidal
sols) into the blood stream.

The colour of colloids. — The colour of the colloids
depends chiefly on the size of the particles, and only
to a small extent on their composition. Thus, the
smallest particles of colloidal gold, when seen by
transmitted light, are red and the larger ones are blue.2
The colour is, in each case, dependent chiefly on the
scattering effect of the particles on the light trans-
mitted through the liquid. In accordance with
Rayleigh's & Thompson's calculations, the intensity

1 CR., 138, 1904, 521 ; CR. Soc. de Biol, 57, 1904, 33.
* Mee found the relation of the size to colour reversed in some
cases.

20 USE OF COLLOIDS IN HEALTH & DISEASE

of the scattered light varies directly as the sixth power
of the diameter of the particles and inversely as the
fourth power of the wave-length. Hence, the intensity
of the scattered light and the absorption are both
greatest with the smallest particles. Stebbing found
that very little light leaves a colloidal liquid, most of
it being absorbed. Svedberg found that colloidal sols
are often more highly coloured than a true solution of
the same element at the same concentration, but that
the absorption spectra of the colloidal sols and solu-
tions do not differ essentially. W. Ostwald l has
enunciated the law that " with decreasing size of the
particles the absorption band of any colloidal solution
moves to the shorter wave-lengths."

Mayer, Schaffer, and Terroine 2 have shown that
traces of alkali increase the size of the particles if the
colloid is positive, and reduce it if the colloid is negative.
Traces of acid produce the reverse effect. The change
in the dispersion thus effected varies with the colour of
the sols. Zsigmondy3 and Gutbier and Resenschack4
found that, on adding coagulating reagents, the colour of
gold sols changes consecutively from red to purple-red,
red- violet, blue- violet, and deep blue, the colloid
eventually separating as flakes of powder or gel.

1 Roll. Chem. Beiheft., 2, 1910 ; n, 409.

2 Comptes r endues, 1907, 145, 918.

3 Zier, Erkentniss der Koll.

4 Z.f. anorg. Chem., 1904, 39, 112.

CHAPTER II

ANIMAL AND VEGETABLE FLUIDS

THAT animal and vegetable fluids are largely colloidal
in character is a fact which is now unquestioned, but
little is known as to their precise nature. Thus, the
particles in cow's milk can be demonstrated under the
ultra-microscope, but those in human milk are too
minute. This suggests that in adapting cow's milk
for feeding infants, it is not sufficient to endeavour to
match the ordinary chemical analysis of human milk,
but that cow's milk should be treated in such a manner
that the product is in a similar colloidal state to that
of the human milk. The valuable superiority for
infant use of milk to which barley water, gruel, or
other starchy solution has been added has long been
known, but few have, as yet, realised that it is due to
the protective action (in a colloidal sense) of the added
substance. Gelatin, gum-arabic, or preferably gum-
acacia, have an even stronger protective action, and
they possess the further advantages of being easier to
prepare and of altering the composition of the milk to
a less extent, whilst making it physically much more
like human milk.

In human milk the protective colloid is lact-albumen,
which is present to the extent of 1-3 per cent (i.e. equal
to the casein present), whilst cow's milk contains only
0-5 per cent of lact-albumen and over 3 per cent of

21

22 USE OF COLLOIDS IN HEALTH & DISEASE

casein. Of all the domestic animals, asses' milk bears
the closest resemblance to human milk, both in
chemical and colloidal properties.

The coarse particles of curd which are formed when
cow's milk is coagulated by acids or rennet may be
replaced by finer, more flaky, and more porous curds
by diluting the milk with water, by adding lime-water
(though this tends to prevent the coagulation altogether
and so may unduly delay its digestion or even cause it
to be passed out of the body of an infant in the un-
digested state), and by the use of one of the protective
colloids previously mentioned.

Bearing in mind its colloidal nature, human milk
can best be imitated by using cow's milk as the basis
and adding the following : (a) cream sufficient to
raise the total fat present to 3-8 per cent (about 3 per
cent of the final mixture being required usually) ;
(b) milk sugar to raise the total sugar content to
6-2 per cent (about 3 per cent of the total mixture
being usually required) ; (c) about I per cent of lact-
albumen, or 2 per cent of gelatin, or a considerably
larger percentage of starch in the form of barley water,
etc., as the protective colloid ; and (d) sufficient
water to effect the solution of the protective colloid
and the sugar. If there is any risk of the cow's milk
not being quite fresh, part of the added water may
wisely be replaced by a tablespoonful of lime-water,
which will neutralise any trace of acidity in the milk
and will therefore increase its keeping power.

In the same way chemical analysis alone does not
determine the value of even the essential properties
of a foodstuff ; its physical condition — particularly

ANIMAL AND VEGETABLE FLUIDS 23

if it is a colloidal substance — is of at least equal and
sometimes greater importance. Thus, cheese cannot
be digested by some people as it is too densely coagu-
lated to be readily converted into a colloidal fluid.
By preparing it under conditions which will facilitate
its resuspension, its high value as a food material may
be utilised. The various preparations of casein which
are at present so popular as recuperatives depend
largely on the fact that they are colloidal substances,
which can be resuspended or converted into colloidal
fluids more easily than ordinary cheese or dried milk.
Indeed, the chief test of such a preparation may
usefully consist in an examination of its properties
when mixed with water or other suitable fluid.

The cell-structure of animal and vegetable organisms
closely resembles the cellular structure of the synthetic
cells. The walls of such cell-structures are really
emulsoid gels, the cell-fluid being an emulsoid sol.
The gels which form the cell-walls and membranes of
the body contain albumen- and gelatin-like substances
which swell in water and to a varying degree in solu-
tions of acids, alkalies, and salts. In other words,
living protoplasm is essentially a complex liquid ; the
presence of a network, observed in protoplasm which
has been killed or " fixed " by various reagents, is
not apparently seen in the living material. The so-
called cell-wall of the protoplasm of some low forms
of life appears to have both the properties of a solid
and of a liquid substance, and in this respect resembles
the film of a soap bubble. For example, Chambers has
recently (1917) found that a needle can be repeatedly
passed into living protoplasm without injuring it

24 USE OF COLLOIDS IN HEALTH & DISEASE

in any way and without leaving any trace of its track.
Bacteria, etc., penetrate the cell- wall in a similar
manner without damaging it, just as well as through a
soap-bubble. The outer layer of protoplasm is not,
however, identical with the membrane to which the
cells owe their semi-permeable properties.

When a cell dies it passes from an emulsoid sol into
an emulsoid gel state and thereby changes its character
and reactions, one of the most remarkable differences
being that the liquid of the dead cell freely mixes with
the surrounding watery solution, whilst the contents
of the living cell do not escape in this manner. Under
normal conditions living cells are non-conductors and
are largely impermeable, but under the influence of
certain ions they become permeable and allow electri-
cally charged particles to pass freely through them.
When certain cells are immersed in a saline solution
the sodium ions present increase their permeability ;
the addition of calcium ions restores them to their
normal condition. Hence simple solutions of salts do
not form an efficient substitute for the blood or for
the sea-water in which marine creatures live ; a small
but significant proportion of calcium salts is essential
unless a colloid, such as gelatin or gum-acacia, is added
in sufficient proportion to give the saline solution an
osmotic pressure as high as that of the blood. The
selective permeability of living cells is very remarkable.
Acids which are soluble in the cell or in the analogous
liquid bodies readily penetrate the cells, but other
acids and strong bases do not. Weak bases (including
ammonia and the amines) penetrate the cells without
difficulty.

ANIMAL AND VEGETABLE FLUIDS 25

Although sodium hydroxide does not enter the
living cells it greatly increases the rate of oxidation
processes in the cells. This is due to the fact that the
cell-wall is really a concentration of the components
of the protoplasm of the cell, and in the presence of
sodium hydroxide the normal equilibrium is upset,
and this produces marked changes in the cell, not-
withstanding the fact that the sodium hydroxide
does not penetrate into it.

The cell materials, whilst being typical emulsoids,
behave in a far more complex manner than the syn-
thetic emulsoid gels or the natural or synthetic sus-
pension sols. Thus, albumen is electrically neutral and
is precipitated by basic emulsoids (as histone) and
basic sols, which are positive sols. It is also precipitated
by acid emulsoids, such as silica sol and acid dyes,
which are negative sols. Tannin and gallic acid behave
similarly. Perrin l has suggested that primary cell
growth and cell division are essentially colloidal in
nature, an idea which is, to some extent, supported by
galvanotropism in microscopic animals.2 If this is the
case — and there is much evidence in support of it — a
study of the changes in the viscosity of the body fluids
under certain circumstances,3 the influence of certain
salts on the properties and action of the blood,4 and
the laws regulating the permeability of the cell-walls
for salts and colloids in the human body are bound to

1 Journ. Chim. Phys., 1904, II, 607.

8 Miller, Journ. of Physiol., 1907, 215. Buxton and Rahe, Zs. /,
D. Ges., Bischam, XI, n to 12, p. 479.

8 Rachlmann, Bert. kin. Wochensch, 1904, Heft. 8 ; Deutsche
Med. Wochensch, 1904, Heft. 29.

* Nanes, Chem. Beih. Physiol., 1910, 40, 327.

26 USE OF COLLOIDS IN HEALTH & DISEASE

advance our knowledge of the normal action of the
body and to increase our power of treatment when it
is diseased. As an instance of the advance which has
been made since the colloidal nature of animal and
vegetable substances has been appreciated, it may be
noted that when investigating albumens and their
digestive products, students of physiological chemistry
have long been puzzled by the complexity of the
mixtures precipitated by various reagents, such as
ammonium or zinc sulphate. It has been impossible
to effect really satisfactory separations of such sub-
stances by ordinary chemical processes, but their
strikingly different behaviour towards colloidal metals
has opened out a new field of research which it is
anticipated will have far-reaching results. Another
interesting result of the recognition of the colloidal
nature of blood may suitably be mentioned here.
For many years it has been held that the oxygen in
the blood was in the form of a compound of oxygen
and haemoglobin, but in 1907 Wolfgang Ostwald
pointed out that all the available data may be arranged
to form graphs or curves which are typical of adsorption
and there can be little tfoubt that both the oxygen and
the carbon dioxide in the blood are in an adsorbed
condition.

Red blood - corpuscles are negative, but can be
precipitated by both positive and negative sols.
Henri l assumes that they are surrounded by a pellicle
which can adsorb salts, such as magnesium and
calcium sulphate. These salts act on any precipitable
sol, producing a coagulum around the corpuscles ;

1 Compt. Rend., 1904, 138, 1461.

ANIMAL AND VEGETABLE FLUIDS 27

they can be removed by diffusion into an isotonic
sugar solution, after which blood-corpuscles are much
less susceptible to precipitation by sols.

Blood-corpuscles which have been soaked in solu-
tions of salts — especially chlorides and sulphates — are
made more easily precipitable by sols, especially ferric
hydroxide sol.

The fact that the blood is a typical complex
colloidal fluid is now accepted, and this is the basis
of the treatment of numerous diseases, though many
physicians have scarcely recognised it. The colour-
ing matter — hczmoglobin — is definitely colloidal, and
hence it is not surprising that the colouring matter
obtained from different animals differs both in its
composition and properties. In red corpuscles from
the human subject, the haemoglobin is associated with
a complex of various substances, some colloidal and
others crystalloidal, and with a liquid which is isotonic
with a solution of nine parts of common salt in a
million parts of water. If the red corpuscles are
immersed in a more dilute solution than this they
swell, and haemoglobin gradually passes from them to
the external solution (hczmolysis). The importance
of this phenomena — which is characteristic of colloidal
gels — will be appreciated when considering the effect
of colloidal substances in diseased conditions of the
human subject.

The characteristic behaviour of some of the waste
products of the human organism is also due to their
colloidal character. Thus, urine contains colloidal
substances which normally prevent the uric acid from
separating. This colloid may be removed by dialysis

28 USE OF COLLOIDS IN HEALTH & DISEASE

or precipitated by alcohol ; it appears to be a deriva-
tive of nucleinic acid. Urines which are deficient in
this protective colloid may be prevented from deposit-
ing uric acid on cooling by adding to them a suitable
colloid. Unfortunately, those colloids, such as gelatin,
which are most successful in vitro, are absorbed by the
alimentary tract and therefore do not reach the
bladder in sufficient quantity to admit of their being
used in certain urinary diseases. Experiments with
other colloids are now being made. In this connection,
it should be noted that alcohol reduces the rate of
diffusion of salts in gels, whilst urea, chlorides, and
iodides increase it.

CHAPTER III

THE HYGIENIC USES OF COLLOIDS

THE important part played by colloidal sols and gels
in the maintenance of hygienic conditions is seldom
realised by those whose attention has not been called
to this aspect of the subject. The removal of harmful
impurities in water, the disposal of sewage in an in-
nocuous manner, and the effective disposal of " dirt "
are all largely dependent on some colloidal properties,
the precise nature of which is by no means well recog-
nised by many of those engaged in the purification of
water, or sewage, or who are habitual users of soap and
other detergents.

The study of colloids in relation to these subjects is
comparatively new, and much has yet to be learned.
On the other hand, it is interesting to note how much
of the best modern practice and use of colloidal pro-
perties has been reached by persistent investigation
on the lines which had little or no bearing on the
recognition of the real nature of colloids. Now that
the importance of the colloidal state has been recog-
nised in other branches of industry and science, it is
surely not too much to hope that it will lead to equally
striking improvements in the sphere of hygiene. A
few words on each of the important subjects of sewage,
water, and soaps must, however, suffice.

Sewage. — Sewage consists essentially of water con-
39

30 USE OF COLLOIDS IN HEALTH & DISEASE

laminated with excrement, kitchen- and other domestic
refuse, and matter washed from roads ; in some areas
it may be further contaminated with other waste
products from factories, or other industries. This
contaminated matter is in three forms : (a) in sus-
pension, as silt, sand, paper, rags, faeces, vegetable and
animal matter, etc. ; (b) colloidal matter in solution
or pseudo-solution ; and (c) in true solution. In
purifying sewage the chief purpose is to separate the
matter in suspension and to render harmless that in
colloidal and in true solution. The chief difficulty in
dealing with sewage is that the matter in colloidal
solution prevents the effective removal of the coarse
material in suspension, as well as assisting in keeping
it in suspension in larger proportions than would
otherwise be the case. Hence, if the colloidal matter
can be precipitated in a suitable form the most serious
difficulty in sewage treatment is overcome.

The complex nature of sewage is such that it is
impossible to treat each of its constituents separately,
and this adds to the difficulty of purification. It is,
however, recognised that the most difficult constituents
are the colloidal sols, and these can be precipitated
in accordance with the recognised methods for pre-
cipitating other colloids. The most successful chemical
methods of treatment depend on a recognition of this
colloidal character and on the coagulation of the
colloidal sol by the addition of some other substance
carrying an electric charge of the opposite sign. Ferric
and aluminium hydroxides have been largely used for
this purpose, and they are quite efficient. Their great
drawback is the cost of treating such enormous volumes

THE HYGIENIC USES OF COLLOIDS 31

of liquid by any process of sedimentation and filtration
to remove the precipitated colloid and the difficulty
hitherto experienced in converting this colloid into a
useful material. The method which appears most
likely to prove of value consists in utilising the fact
that water which has been violently agitated with, or
has fallen through, air may become positively charged,
and these electrically positive particles then effect the
coagulation of the negatively charged colloids in the
sewage. Hence, by agitating the sewage with air,
under suitable conditions, a complete coagulation of
its colloidal content is rapidly effected at a low cost,
and the precipitate is one which settles with extra-
ordinary rapidity. In the well-known " activated
sludge " process, air is blown through the sewage, the
inventors of this process having apparently failed to
realise that the electric charge of the water particles
is at least equally as important as the oxidising power
of the air. A modification of this process, in which
the water is charged positively by agitating it super-
ficially with air, offers still greater prospects of success,
as it avoids the use of " chemicals " and the costly
supply of large quantities of air. In this connection it
is interesting to note that beneficial action of the air
at the seaside is probably due more to the particles in
it which have been positively charged by the violent
beating of the waves on the -shore, than to the ozone
to which this action is usually attributed. These
positively charged particles, reacting with the nega-
tively charged bacterial and other undesirable colloids,
precipitate them and render them harmless.

The purification of sewage is complicated by the fact

32 USE OF COLLOIDS IN HEALTH & DISEASE

that the precipitation of the colloidal and suspended
material is not sufficient to remove all the putrefactive
constituents : though the greater part is so removed.
The remainder appears to be most advantageously
treated by bacterial action, especially by the activated
sludge, or similar process, and, as it happens, the two
processes of precipitation of the colloids and the
development of bacterial action can in most cases be
carried on simultaneously. The action of bacteria
alone (as in a septic tank) does not appear to affect
the proportion of colloidal matter to any serious
extent, so that where the purification is confined to
bacterial treatment the precipitation is more prolonged,
and the final purification of the liquid is much less
complete than when the colloids are precipitated in
the presence of, or prior to, the action of the putrefying
bacteria.

The sludge produced by the precipitation of the
colloidal matter by electrically charged air, with or
without the action of the activated sludge, is a fairly
stiff material which settles rapidly and is easily
filtered, whereas the ordinary sewage sludge is largely
liquid. The sludge may suitably be subjected to
anaerobic bacterial action, whereby it is converted into
a more dense and granular material which is free from
the objectionable qualities of the untreated sludge.

The purification of water. — The artificial purifica-
tion of water is effected by colloids :

(1) A colloidal coating on the grains of sand in the
filter retains (by neutralising the charge) all the
bacteria, etc., but not the colouring matter.

(2) Aluminium sulphate, or ferric sulphate (with or

THE HYGIENIC USES OF COLLOIDS 33

without alkali), is added to the water, and causes a
precipitation of the positively charged alumina, or
ferric oxide, which reacts with the negatively charged
bacteria, clay, etc., and precipitates them. Simultane-
ously, the positively charged colouring matter is pre-
cipitated by the negatively charged SO4 ions, whilst
any true colouring matter is adsorbed by the precipi-
tated hydroxides. Any excess of alumina, or ferric
oxide, is precipitated by agitation.

Sometimes it is best to add the alkali first ; some-
times only after the aluminium or ferric sulphate.
The latter is preferable when there is much colouring
matter to be removed.

The natural purification of muddy water is largely
dependent on its colloidal character. Thus Skey l
has shown that suspended mud is precipitated by
electrolytes, including those in sea water. Hence,
when a muddy river flows into the sea the proportion
of mud which settles out, owing to the slower current
in the mixed water, is insignificant compared with
that which is precipitated by the electrolytes in the
salt water. Schloesing 2 has shown that deltas are
chiefly due to this cause.

Soaps. — Sir Edwin Chadwick was a firm believer in
the idea that the effectual preventative of all forms of
epidemic, endemic, and most other diseases, is the
entire removal of all conditions of dirt, including foul
air, defective drainage, and dirty surfaces of all kinds.
He was most emphatic as to the necessity of personal
cleanliness, and on one occasion he declared that if a

1 Ghent. News, 1868, 17, 160.

2 Journ. Chem. Soc., 1874, 30, 37.

34 USE OF COLLOIDS IN HEALTH & DISEASE

great epidemic were to occur he would proclaim and
enforce the active application of soap and water as
the chief preventative. In any consideration of the
subject of colloids in relation to health and disease,
under the auspices of the Chadwick Trustees, it is,
therefore, desirable to point out that the detergent
action of soap to which Chadwick and his colleagues
attached such importance is almost wholly due to its
colloidal character, by means of which it is able to
reduce the surface tension between other solids
(" dirt ") and water, and to effect the removal of the
former by a process of colloidal solution. It is a
striking fact that a i per cent solution of soap will
reduce soot to so fine a state of subdivision that it will
pass completely through any filter, and will remain
suspended indefinitely. In a 2 per cent solution of
soap, on the contrary, the soot will be deposited
almost as rapidly from pure water ! In a similar
manner a solution of soap in water will " disperse," or
bring into " colloidal solution," a sufficient proportion
of " dirt " adherent to any cleansable surface to enable
the whole of the " dirt " to be removed in suspension
in the fluid. The addition of any abrasive or scouring
material — such as finely ground sand or silica flour —
may aid the cleansing process, but the chief feature of
it is, nevertheless, the production of a colloidal solution
of a sufficient proportion of the " dirt " to enable the
remainder to be removed readily.

The peculiar behaviour of soap has puzzled many
investigators, some of whom have doubted its colloidal
character yet have failed to find a complete explanation
in a purely chemical conception. The true nature of

THE HYGIENIC USES OF COLLOIDS 35

soap is most probably shown by Bancroft, who has
suggested that undissociated soap appears to be almost
wholly present in colloidal form, but in the presence
of water the sodium palmitate, or corresponding com-
pound, is hydrolised, the OH ions being largely
adsorbed by the undissociated soap, the adsorbing
substance then becoming an anion.

CHAPTER IV

MICRO-ORGANISMS AND DISEASE

THE microbic origin of many communicable diseases
is now generally recognised, and it is reasonable to
presume a similar cause in many other diseases with
which no specific micro-organism has been identified.
Many of the disease-producing bacteria are sufficiently
large to be readily visible under a powerful micro-
scope, but others, such as those relating to yellow
fever, foot-and-mouth disease, and tobacco disease,
are too small to be directly visible. Their existence
has been discovered indirectly by means of the
ultra-microscope — an instrument which is described
later.

Whilst recognising the remarkable advances in the
treatment of many diseases which have resulted from
the recognition of their bacterial or protozoal origin,
the fact still remains that by far the most marvellous
preventatives of disease are contained within a normal,
healthy body, in which, as Lister has clearly demon-
strated, bacteria can only establish themselves when
conditions have arisen which create a state of un-
healthiness.

The period in which all zymotic diseases were
attributed solely to the introduction of bacteria, or
protozoa, into the otherwise healthy subject is,
happily, passing away, and pathologists and others

36

MICRO-ORGANISMS AND DISEASE 37

are increasingly recognising as a fact the necessity for
the bodily conditions being suitable before the disease
germs can multiply extensively in it. As a result of
the wide recognition of this fact — originally pointed
out, though expressed in different terms, by Sir Edwin
Chadwick and his colleagues — it is now seen that
attention should be concentrated on the state of the
body fluids and cells as well as on the invading micro-
organisms. Now that the colloidal nature of the body
fluids and cells has been recognised, it is possible to
make considerable progress in maintaining them in,
or restoring them to, a suitable condition on purely
chemical or physio-chemical lines. The subject is too
vast to discuss in detail in the present volume, but
briefly it is now admitted that if the normal colloidal
condition of any of the more important body fluids, or
cells, is disturbed by the advent of undesirable electro-
lytes, salts, or colloids of the " opposite " sign, condi-
tions are produced which provide a suitable nutrient
medium for many of the disease-producing germs which
are constantly coming into contact with the body. If
the altered body fluids or cells can be restored to their
normal colloidal state without seriously damaging
any other portion of the subject, the invading germs
will soon perish and will be removed from the body
by the normal processes of life. If this view of the
matter is correct, it is of far greater importance to
restore the disarranged colloidal state to its normal
condition than it is to endeavour to kill the invading
germs without otherwise altering the state of the
diseased or altered cells or body fluids. In the latter
event it will only be a question of time before the

38 USE OF COLLOIDS IN HEALTH & DISEASE

patient is attacked by further organisms, and these
attacks will be continued until, by some means or other,
the diseased organs regain their normal colloidal state,
or until they are atrophied or have been removed by
means of a surgical operation. If, on the contrary,
the normal colloidal state of the diseased organ can
be restored, the body as a whole is well able to effect
a complete recovery without any serious risk or delay.
The importance of the influence of the " soil " upon
the " seed," and the predisposition of the individual
body to attacks by germs, has been established by
Sir Wm. Collins in an essay published in 1884,
dedicated to Herbert Spencer, who " regarded it as
opening the way to a considerable reform in pathology."
If his theory (as to underestimated influence of evolu-
tion on the specific disease-producing effects of or-
ganisms whose cycle may be only a few hours or even
less than one hour, and whose rate of propagation is
incalculable) is approximately correct the necessity of
maintaining the body fluids in the correct colloidal
state must be obvious. The rational treatment of
zymotic disease must not depend solely on the destruc-
tion of the germs by means of which the disease is
propagated ; the requisite attention must also be
paid to the " soil," or medium, in which the germs
exist in the body.

This is readily understood when it is realised that
emulsions of bacteria may be regarded as suspensoids
protected by an emulsoid sol. They are precipitated
by definite amounts of electrolytes, such as acids,
heavy metal ions, and by aluminium and ferric ions,
as are ordinary suspensions. Emulsions of bacteria

MICRO-ORGANISMS AND DISEASE 39

are not precipitated by alkalies and are not protected
from precipitation by other emulsoids, such as gelatin,
as are many negative colloids. The addition of an
immune serum to a bacteria sol greatly increases
the sensitiveness of the latter to electrolytes, and
apparently destroys the protecting part of the bacteria
sol, which thus becomes a suspensoid sol.

Unfortunately, the colloidal characteristics of fluids
containing bacteria are highly complex. Many of their
reactions appear to be partly of a colloidal and partly
of a chemical nature. Thus, the reaction between
bacteria and agglutinins, including emulsin and gelatin,
resembles an adsorption, but as sols of any one kind of
bacteria are affected only by the agglutinin produced in
the serum by the injection into the animal of the same
kind of bacteria, this fact seems to imply the existence
of definite chemical properties. On the other hand
some bacteria sols are definitely affected by inorganic
colloids in a manner which suggests both a colloidal and
a chemical action.

Toxins and anti-toxins. — Toxins are the products of
bacterial life, and are to some extent analogous to the
excreta of the higher organisms. They are decom-
posed and rendered harmless by a number of sub-
stances, of which special interest attaches to those
other products of bacterial life (such as immune serum)
known as anti-toxins. Thus, when a suitable immune
serum is added to the corresponding bacteria sol,
the latter does not coagulate, even after dialysis, but
it becomes so sensitive to electrolytes that the latter
coagulate it easily. This is explained by the suggestion
that the agglutinin in the serum destroys a protecting

40 USE OF COLLOIDS IN HEALTH & DISEASE

agent which is assumed to be present in the bacteria
sol.

A mixture of the corresponding agglutinin and
bacteria sol is not precipitated by OH ions, but
readily so by acids and salts of the heavy metals.
The addition of salts precipitates the colloids if there
is an equivalent of agglutinin to bacteria sol. If either
colloid is greatly in excess of the other no precipitation
occurs.

Both toxins and anti-toxins are colloidal, particu-
larly the latter. Thus, when a diphtheria toxin is treated
with its anti-toxin, the reduction in toxicity depends on
the manner of administration. If the anti-toxin is
added in small quantities at long intervals much more
anti-toxin is needed.

Field and Teague 1 found that both toxin and anti-
toxin migrate distinctly in an electric field. There
may be a chemical compound between the toxin and
the anti-toxin, but more probably there is a mutual
adsorption, the reaction being wholly colloidal. A
difficulty exists with both explanations, inasmuch as
diphtheric anti-toxin is the only one which will neu-
tralise the diphtheria toxin, and, at present, both
these substances appear to possess both chemical and
colloidal properties.

In addition to the difficulty of treating such com-
plex substances in accordance with general principles,
there is the further disadvantage that, whilst blood
serum has normally a positive charge, most of the sols
of the pathogenic bacteria are not coagulated by fluids
with such a charge. This remarkable behaviour may

1 Journ. Exp. Med., IX, 86.

MICRO-ORGANISMS AND DISEASE /ji

be due in part to the presence of a powerful protecting
agent, but if this is correct it only transfers the diffi-
culty without eliminating it. The value of a suitable
immune serum lies in its power of increasing the
sensitiveness of the bacteria sols to electrolytes, and
thus facilitating their precipitation. Much work is
now being done in the endeavour to ascertain the
chemical or colloidal nature of the various agglutinins,
and until the results of this work have been published
judgment on this matter must be deferred. The fact
that so small a quantity of the agglutinins has such
far-reaching effects is highly confirmatory of their
essentially colloidal character, and their peculiar
specificity may ultimately be found to be due to the
simultaneous production by the bacteria of a specific
protecting agent which, in its turn, may be decomposed
by the elementary colloidal sols, though it resists the
attack of compound sols.1

1 Further information on the current views of the reactions
between agglutinins and bacteria will be found in :

Immuno-chemistry, S. Arrhenius (Macmillan and Co.).

Le mechanisms de V agglutination, J. Bordet. Annales de VInst,
Pasteur, 13, pp. 225 to 272.

" Mechanism of the Agglutination of Bacteria by Specific Sera,"
W. J. Tulloch, Biochem. Journ., 8, pp. 294-319.

CHAPTER V

POISONING — DIGESTION AND COLLOIDS

THE similarity between the poisoning of animals and
the stoppage of the reaction of certain metallic sols by
small quantities of well-known poisons is very striking.
Thus, the presence of a trace of prussic acid will reduce
the speed of reaction of platinum sol on hydrogen per-
oxide to half the normal rate, and a somewhat larger
proportion will cause the reaction to cease. Enzymes
and ferments are " poisoned " in a similar manner.

This great similarity between animal "poisoning"
and a stoppage of a relatively simple chemical reaction
is very important, as it suggests many other points of
possible resemblance which are worth further study
and opens out large fields of chemical research in
connection with biological and physiological problems.
Moreover, the relative ease with which the effect of
metal and other sols on chemical reactions can be
studied and controlled, suggests that similar reactions
— equally well controlled — may be effected in the
human subject with far-reaching results.

Digestion and colloids. — The reactions which occur
in normal digestion result in the production of sub-
stances which are able to pass through the membrane
of the alimentary canal into the blood stream. At the
first glance, it may be supposed that such a passage
would exclude all colloidal sols, though precisely the

42

POISONING— DIGESTION AND COLLOIDS 43

opposite is the case. It has been found that in the
presence of a crystalloid, such as common salt, the
passage of colloidal sols through the membranes is
considerably increased, thus showing the importance
of the salt to the animal and human organism. The
advisability of eating salt with so typical a colloidal
gel as a boiled egg is thus seen to be based on a physi-
ological requirement, and not merely on a matter of
taste.

It is important to observe that the products of
digestion, and some other colloidal substances occur-
ring in the animal organism, consist of much smaller
particles than artificially prepared colloids. Thus
haemoglobin will pass through much less permeable
membranes than colloidal metals, and serum, albumen,
and - protalbumoses are correspondingly finer in the
order given. This may partially account for their
ability to pass through certain membranes. Donnan
has shown that the permeability of a membrane to a
simple ion is greatly affected by the presence of a colloid.
In some cases the colloid is hydrolised by some un-
known means in the presence of an inert membrane
and an electric potential is created. In both these
cases the difference between a living and a dead
organism must not be overlooked, though its import-
ance should not be exaggerated.

The nature of materials used for food is so varied
and the products of their digestion are so numerous
that for anyone who realises their essentially colloidal
nature, it is easy to see that any change of state may
produce a profound disturbance in the whole system,
and that such a disturbance may appear to be quite

44' USE OF COLLOIDS IN HEALTH & DISEASE

out of proportion to the chemical activity of any
compound or element which may be present. For this
reason there can be no general cure for all forms of
indigestion, as each has its specific cause. If any such
general remedy could exist it would be a substance
which would effect the conversion of any food sub-
stance into a colloidal sol of a nutritive and non-toxic
character.

Similarly, it is possible to see that improper food,
unsuitably prepared, the absence of sufficient air, and
the neglect of sanitary and hygienic precautions may
effect changes which are quite disproportionate to the
actual weight of " dirt " or other objectionable matter
present. The normal state of the body fluids is easily
disturbed, and whilst it is almost as easily restored
under healthy conditions of life, restoration is made
difficult or even impossible if the conditions are un-
suitable.

CHAPTER VI

USE OF COLLOIDS IN MEDICINE

COLLOIDS have long been used more or less unwittingly
in medicine, the colloidal state being the only one in
which certain medicaments can be administered, whilst
others — exhibited as tinctures — are converted into
colloids on dilution. Such crude forms are necessarily
subject to many disadvantages, and the true signifi-
cance of their colloidal nature not having been recog-
nised it is only natural that they should not be either
as certain in action nor as free from objectionable
properties as colloids which have been specially pre-
pared so as to secure the maximum colloidal efficiency.
Thus, tincture of podophyllin and other resinous sub-
stances are precipitated on diluting them sufficiently
with water, with the consequent formation of a small
proportion of colloidal sol. This sol is the most active
therapeutic constituent, and the remaining material
is only useful medicinally when it has been converted
by the action of the body fluids into an assimilable
form. This conversion is accompanied by a serious
loss of material, both directly, by its conversion into
inert or undesirable substances, and indirectly by its
transport to portions of the organism where it cannot
exercise the desired effect. Consequently, the acci-
dental production of therapeutic agents in colloidal

45

46 USE OF COLLOIDS IN HEALTH & DISEASE

form results in uncertainty of action, the production
of undesirable side reactions, and necessitates the
administration of large doses, the greater part of which
is inert, or, in some cases, somewhat harmful to the
patient. These disadvantages were unavoidable so
long as no satisfactory colloidal preparations were
available, but with the increase in the number and
efficiency of the latter, the science of pharmacology
and the practice of medicine will, it is anticipated,
make rapid progress.

The most widely-used preparations of a highly
colloidal character are the embrocations and liniments
used externally or those administered internally in the
form of emulsions of cod liver oil, petroleum, etc.
These have proved a convenient and satisfactory means
of introducing certain liquids in varying degrees of
dilution, under conditions in which ordinary solvents
are inadmissible.

Such emulsions are truly colloidal in character, the
active liquid being usually present as the disperse
phase, whilst the continuous phase is of a different
character, such as water to which a small proportion
of an emulsifying agent — usually albumen or a soap —
is added. Other active therapeutic agents may usually
be present in solution in the aqueous phase, it being
an additional advantage possessed by emulsions that
they permit the simultaneous exhibition of two or more
active agents in any desired degree of concentration.

Emulsions of the kind just mentioned must not be
confused with the colloidal sols described later. Even
the most elegant emulsions are very coarse compared
with the sols, and the penetrating power and general

USE OF COLLOIDS IN MEDICINE 47

activity of the latter are correspondingly greater than
that of emulsions.

The customary administration of any remedy —
quite apart from the particular substance or drug
which it may contain — is primarily based on the
assumption that such a remedy has a specific reaction
either with a substance in the body (such as the action
of pepsine on the undigested food) or an equally definite,
but less understood, reaction whereby certain organs
are stimulated to unusual effort, as in the administra-
tion of emetics or purgatives. It is generally supposed
that the effect is roughly proportional to the dose
administered, though it is recognised that the optimum
dose differs with different patients. In some cases—
particularly in the administration of mercury com-
pounds— it is also realised that minute quantities
administered frequently have an effect which is
entirely different from that of the same substance
administered in a single and large dose. Still more
striking is the fact previously mentioned, that with
some remedies the changes are out of all proportion
to the dose which may be administered. The great
changes which occur in certain diseases are prevented,
and the normal state is restored by quantities of
chemical agents which appear ridiculously small when
regarded as definite reagents. But such a condition
is a well-known characteristic of colloidal fluids, in
which even a few drops of solution will effect a solidifica-
tion of a large volume of material. The coagulation of
milk by rennet or acid, and that of blood after a short
exposure to air, are typical illustrations of such a
change. The extraordinarily rapid action of minute

48 USE OF COLLOIDS IN HEALTH & DISEASE

doses of some poisons is probably a similar effect.
Bearing in mind these great changes in condition
which result from the action of small amounts of active
agents, it is easy to see that a slight excess or deficiency
of some element present in minute proportions in the
organism may effect a profound change in the action
of that organism. The deficiency of phosphorus in
certain nervous diseases is well recognised, and various
methods of supplying it have met with encouraging
results. There is, however, a curious idea extant, that
an element in which there is a deficiency should be
administered in the same form as that in which it
exists in the body. For instance, there is a popular
idea that glycophosphates are superior to any other
phosphorus compounds, because the phosphorus in
the brain is chiefly found as a glycophosphate. This
is quite a mistake, as will readily be seen if other
analogous cases are considered. For instance, sugar
is stored in the liver in the form of glycogen, but to
administer glycogen orally would be useless, as it is
destroyed in the stomach. It is essential that any
medicine should be administered in such a form that
its essential constituent will travel through the body
until it reaches the part where it is required, and that
it shall arrive at that organ in such a state as to be
used to the greatest advantage. To administer lecithin
because lecithin has been isolated from the brain
substance is to misunderstand the chemical changes
which take place in assimilation, and to supply the
subject with a material in a form from which it has to
be converted to something more suitable. The fact
that this conversion occurs merely shows how marvel-

USE OF COLLOIDS IN MEDICINE 49

lous an alchemist is the human organism ; it is no
reason for the administration of chemical agents in
unsuitable forms.

The principle underlying the treatment of disease
by the administration of chemical compounds is much
more easily understood when it is realised that the
reactions deal largely with colloidal materials, and
that they may be effected most efficiently and with a
minimum of disturbance to other organs by basing
the treatment on this principle.

This fact has been recognised in a half-hearted way
for some years, but its implications were scarcely
realised until a few years ago. This was due to a
number of causes, of which the two most important
were the difficulty of studying the special properties of
substances in the colloidal state with the appliances
then at hand, and the difficulty experienced in obtain-
ing active colloidal fluids which were isotonic with
and therefore stable in the body fluids to which they
were applied. The work of Ehrlich and others may,
in certain respects, be regarded as attempting to
supply elements of a highly toxic character, such as
arsenic, in such a form that they would affect the
disease-creating germs without harming the patient
or host. Such methods suffer from obvious draw-
backs, such as the caustic, irritant, or even toxic effect
of the stabilising organic compound, and as the com-
plexity of the compounds was increased, their essentially
colloidal character gradually receded into the back-
ground of the minds of the investigators until it was
wholly overlooked.

Colloidal fluids only retain their characteristic

50 USE OF COLLOIDS IN HEALTH & DISEASE

properties so long as their active ingredient is in a
properly dispersed and suitable colloidal state. In the
presence of very small quantities of certain salts, the
ions or ultimate particles of which have an electric
charge which is opposite in sign to that of the active
colloid, the latter will be coagulated and rendered in-
active, unless they have been protected by some other
colloid. In the latter case, coagulation or precipitation
can only occur when the protective agent has been
destroyed or removed.

Medical possibilities of colloids. — From what has
already been stated it will be seen that the application
of colloidal sols to diseased conditions of the human
body is distinctly encouraging, but like all other new
ideas it has had its share of drawbacks and discourage-
ments, due in almost every instance to ignorance.
Among other causes the premature supply of improperly
prepared and unstable colloids has been one of the
most serious sources of trouble.

Shortly after the definite recognition of the colloidal
nature of the chief body fluids was effected, the
enormous possibilities which might result from the
application of colloidal disinfectants and medicines
were rapidly recognised by German investigators ; a
number of colloidal substances was placed on the
market and their therapeutic properties were carefully
and vigorously " boomed " in this country and
elsewhere.

It was soon found, however, that most of these
preparations rapidly deteriorated in value ; some of
them were so unstable that they contained no active
colloid at the time when they were used, and others —

USE OF COLLOIDS IN MEDICINE 51

not being isotonic with the physiological fluids in the
diseased organs to which they were applied — were
coagulated immediately after their administration to
the patient.

Many attempts to secure stability by means of
organic compounds were made, and eventually the
main difficulties were overcome — especially with regard
to certain colloidal elements. One of the chief causes
of trouble was due to the fact that if a colloidal sub-
stance is prepared in the purest possible state in a
disperse medium (such as water) of great purity, the
product will be highly unstable. Even a trace of
material of the opposite electric sign will cause the
precipitation of the colloid. If, on the contrary, the
substance is converted into the colloidal state in the
presence of certain other colloids and of certain salts,
the desired colloid will not have its activity impaired
in the least degree, but it will be quite stable and can be
mixed with normal blood or other body fluids without
being rendered inactive by them. The salts and
additional colloids exercise a protective action on the
colloid chiefly under consideration, and so enable it to
be used under circumstances which would otherwise
be impossible. The therapeutic action of the protec-
tive agent must not be overlooked ; usually it appears
to be negligible, but occasionally it has been observed
to be of considerable importance.

Failure to realise the necessity for stabilising the
remedial colloids by rendering them isotonic with the
blood serum, and protecting them against precipitation
by undesirable agents, was thus one of the chief causes
of failure of the earlier investigators, but it has been

52 USE OF COLLOIDS IN HEALTH & DISEASE

entirely overcome in the case of a large number of
colloidal sols mentioned later, and these are quite
stable and effective. Yet in consequence of the failure
which resulted from such ignorance of the essential
properties of all colloidal fluids, British medical men
were at first rightly averse to using colloidal pre-
parations, and the subject remained in a parlous
state for some time. In fact, it so remained until
suitable methods of preparing stable and isotonic
colloidal sols were discovered in 1910-1913 by the
late Henry Crookes — a son of Sir Wm. Crookes — and
were extended and improved by his colleagues and
successors, as well as by other investigators.

CHAPTER VII

PREPARATION AND ASSAYING OF COLLOIDAL SOLS

ANY substance can be obtained in the colloidal state
if the conditions under which it is prepared are suit-
able. All colloidal sols are prepared by either

(1) Dispersing or breaking down the larger particles
in the presence of a suitable fluid ; or

(2) By " condensing " particles in solution until
they form larger suspensoid particles.

The dispersion may be effected —

(a) Mechanically, as by grinding the substance
and fluid together ; l

(b) By dilution, as when a gum is dissolved in
alcohol solution and the solution poured into a large
volume of water ;

(c) By using electrodes of the substance to be dis-
persed immersed in a suitable liquid and passing an
electric current through them ;

(d) By the addition of a suitable electrolyte (such

1 Colloidal solutions must not be confounded with the sugges-
tions made by homcepathists with respect to prolonged trituration
of a solid material or to the administration of small doses at regular
intervals.

No trituration, however prolonged, will convert some materials
into a colloidal sol state, and even those which can be converted
are too much contaminated with non-colloidal material and are
too unstable to be of much service. As regards dosage, it is a
well-known characteristic of all colloidal reactions that if the whole
of the reagent is added rapidly its effect is much greater than if it
is added in small quantities at a time.

53

54 USE OF COLLOIDS IN HEALTH & DISEASE

as an acid or alkali) to a colloidal gel. From the
analogy between this process and that of animal
digestion it is frequently termed peptisation.

The condensation may be effected by chemical
reduction, oxidation, hydrolysis, or double decom-
position. Thus, colloidal gold sol is readily obtained
by reducing a dilute solution of gold chloride, formic
aldehyde, or phosphorus in the presence of potassium
carbonate. Colloidal sulphur sol may be obtained by
adding a solution of sodium hyposulphite drop by
drop to a dilute solution of sulphuric acid, heating
the mixture to 80° C. for a short time, filtering off
any insoluble sulphur and neutralising with sodium
carbonate.

Although many colloidal sols are made by hydrolysis
(i.e. by the action of water on them) this is seldom
used as a method of preparation. The methods of
preparation just indicated do not as a rule yield
colloids which are stable in the presence of serum.
For this purpose they must be modified so as to pro-
duce a stable fluid. It is most important to observe
that it is relatively easy to produce a colloidal sol of
low stability and containing a considerable proportion
of impurities ; it is peculiarly difficult to prepare pure
sols which remain stable when mixed with the blood-
serum and other physiological fluids. Yet the use of
impure and unstable sols is so serious that no pains
must be spared in ensuring the purity and stability
of the sols used for remedial purposes, and particu-
larly those which are administered by intravenous
or intramuscular injection. For these reasons, the
remedial colloidal sols prepared by the amateur should

PREPARATION OF COLLOIDAL SOLS 55

not be used until exhaustive tests have proved their
efficacy and stability. The author is aware of a number
of severe cases of poisoning which were due solely to
the use of impure colloids with a very low degree of
stability. As many colloidal sols of high stability and
suitability for administration either orally or hypo-
dermically can now be purchased, there is little or no
advantage to be gained by medical men preparing
these sols.

The stabilising or protecting of a colloidal sol depends
on its being in a state of equilibrium between the
forces tending to cause these small particles to
coalesce (surface tension) and those tending to cause
dispersion of the colloid throughout the medium.
Stability appears to be due, in most cases, to a union
of the particles to be stabilised with those of the pro-
tective colloid or with ions which have a stabilising
action. Zsigmondy maintains that stability is wholly
due to the equilibrium between the adsorption and
dissociation of ions by colloidal particles. The in-
stability which is most serious in colloidal sols used as
medicines is that which results in coagulation.

Stability is secured in a variety of ways, including
the following :

(a) Preparing the sol in the presence of those sub-
stances in which it is required to be stable, i.e. by
substituting an appropriate fluid for water as a solvent
for the various substances from which the colloid is
produced. Thus colloidal sulphur, prepared in a
solution in which water is replaced by a physiological
salt solution, is much more stable after injection into
the blood than colloidal sulphur prepared in pure

56 USE OF COLLOIDS IN HEALTH & DISEASE

water. On the other hand, the former is liable to set
up undesirable reactions within the body unless
special precautions are taken to remove the undesir-
able salts by a process of selective dialysis.

(b) Adding a protective agent such as gelatin or pro-
talbinic acid prior to producing the sol.

(c) Preparing the sol so that all the dispersed par-
ticles are of the same size and without any appreciable
surface tension in the dispersing fluid.

(d) The presence of chlorine or of other charac-
teristic ions appears to be essential to the stability
of positive sols. If these ions are removed the sols are
unstable.

(e) Removing the greater part (but not the last traces)
of electrolytes. This method is inapplicable to colloids
used for medical purposes.

Assaying sols. — It is of utmost importance to de-
termine the activity of a sol just prior to its use unless
it is definitely known that it is sufficiently stable for
its activity to be relied on implicitly.

The percentage of active colloid cannot be de-
termined by any of the ordinary chemical methods as
the colloidal state is physical rather than chemical in
character. Thus, a colloidal solution of silver gives no
precipitate with a solution of a chloride, a colloidal
solution of iodine does not produce a blue colour with
starch solution. Hence, it sometimes happens that a
chemist may report that a certain solution does not
contain a particular element or compound if the latter
is in a colloidal sol state. By appropriate treatment —
usually by converting the substance into the crystalloid
state — the ordinary methods may be applied, but they

ASSAYING COLLOIDAL SOLS 57

do not differentiate between the proportions of colloidal
and crystalloidal substance when both are present.

The chief methods of determining the activity and
therefore the value of the sol are :

(a) Observation of the movement of the particles
by means of an ultra-microscope.

(b) Observation of the intensity of the Tyndall
phenomena.

(c) Determination of the gold number.

(d) Observation of the time taken for a deposit
to form.

(e) Observation of the effect of the addition of
the solution to serum or other characteristic physio-
logical fluid.

A. Arc Lamp. B. Slit. C. Primary Lens. D. Secondary 'Lens.
E. Condenser ( I in. objective). F. Cuvette. G. Microscope.

FIG. 2. DIAGRAM SHOWING ACTION OF ULTRA-MICROSCOPE

(a) The ultra-microsoope affords the simplest and
most rapid means of ascertaining the activity of the
colloidal particles in a sol. When properly prepared,
colloidal sols are transparent or slightly opalescent,
coloured or colourless, pass readily through a filter
paper, are apparently homogeneous in chemical be-
haviour but under the ultra-microscope are seen to
contain minute particles in a state of rapid motion, the
particles being comparable in size to those of molecules

58 USE OF COLLOIDS IN HEALTH & DISEASE

in crystalloid solutions. In some colloidal sols the
particles are too small for their movements to be
observed in the ultra-microscope (i.e. they are less
than about 30 /UL/UL in diameter) . The ultra-microscope
is based on the fact that the existence of particles
which are quite invisible to direct vision may be readily
recognised by passing a beam of light across the space in
which they occur. The beam of light from a lantern
is in itself invisible, but the particles of dust present
in the air — which are also invisible — reflect the light
in various directions, so that we recognise the presence
of these particles by their action on the light.

Zsigmondy applies the same principle to colloidal
particles by passing a very concentrated and powerful
beam of light horizontally through the liquid to be
examined and then views the liquid against a black
background through an ordinary microscope. If the
liquid consists of a solution of a crystalline salt the
field of the microscope remains dark, but if an active
colloidal substance is substituted the field is at once
occupied by minute specks of light which dart hither
and thither in a wholly irregular manner. The ultra-
microscope consists of a powerful source of light — an
arc lamp or the sun — which sends a beam of light
through a suitable slit 0-002 to 0-02 in. wide and 0-004
to 0-08 in. high, the light being focussed by a telescopic
objective of about 0-4 in. focus. A second similar lens
of about 3 in. focus forms an image of the slit in the
plane of a condenser, the latter consisting of a micro-
scope objective, whereby a reduced image of the slit
is thrown into the solution to be examined. A polariser
may be inserted between the slit and the second lens

THE ULTRA-MICROSCOPE 59

if polarised light is desired, and all extraneous light
may be cut off by suitably disposed diaphragms. The
solution to be assayed is contained in a specially shaped
glass vessel termed a cuvette, which consists of an
accurately shaped rectangular cell with a small tube
at each end to form an outlet and inlet respectively.
By passing a current of specially distilled water
through the cuvette it is readily cleaned and the col-
loidal solution can be admitted, discharged, and the
cell washed as required.

FIG. 3. CUVETTE.

The light passing horizontally through the solution
is reflected by suspensoid particles, and if an ordi-
nary microscope is used to examine the solution in the
cuvette the field will be illuminated by brilliant specks
of light if a colloidal sol is being examined, but will be
dark if a crystalloid solution is used. If the cuvette is
filled with an active colloidal sol, the movements of
the particles are readily observable, and then if to
this active liquid is added another containing either
a colloid of opposite electrical sign or some other sub-

60 USE OF COLLOIDS IN HEALTH & DISEASE

stance on which the active colloid can exert itself, the
field rapidly darkens because the active colloid and
the reagent combine and settle to the lower part of
the cell and so out of the beam of light.

An active colloid which has, for any reason, become
unstable will show very few specks of light in the ultra-
microscope, and their movement will be slow and
wholly different from a freshly prepared colloid. By
this simple means, the activity of a colloidal fluid may
be ascertained in a few minutes and all uncertainties
in this respect at once removed. Without such an
instrument, useless, inactive, and unstable colloidal
preparations might be administered instead of active
ones. The use of an ultra-microscope was particularly
necessary when the uncertain colloids prepared by
electrical methods or by reduction from unsuitable
solutions were used, but at that time, unfortunately,
such instruments were not available in this country.
During the past five years, perfectly stable colloidal
preparations have been available in this country, and
as they can be relied upon, if prepared by a good firm,
the general use of the ultra-microscope is no longer
necessary.

Incidentally, it may be mentioned that the ultra-
microscope has been invaluable in recognising the dis-
similarity between normal and infected serum and the
effect of prepared colloids upon the characteristic
colloidal eccentricity of such substances as syphilitic
serum. Normal serum is a saline colloidal solution of
insoluble protein protected by soluble protein (aliphatic
amino-acids). In syphilis, the proportion of colloidal
matter in the serum is supernormal, and especially in

THE TYNDALL PHENOMENON 61

the cerebro-spinal fluid, and the charge carried by the
protein is positive.

(b) The Tyndall phenomenon first investigated by
John Tyndall,1 who found that light passed through a
gas or liquid containing particles in suspension — even
when these are so small as to be ultra-microscopic—
produce a delicate blue colour the intensity of which
is roughly proportional to the number of particles.
Larger particles produce a white tint as they are not
small enough to scatter only the shortest waves of light.

If a concentrated beam of light from an arc lamp is
passed through a slit placed in its focus, next through
the solution in a rectangular vessel and then observed
with a mounted Nicol prism, it will be found that the
polarisation of the light is affected by the colloidal
particles. If these are less than 100 p.^ in diameter
the polarisation is complete, and the Nicol must be
turned through 90° to depolarise it. For larger ones, a
lesser angle will suffice. If a selenite plate is substi-
tuted for the Nicol prism, the light which has been
polarised almost completely by the solution will pro-
duce vivid colour effects. These coloured rings form
an extremely delicate means of estimating the number
of particles in suspension in the solution, the diameter
of the beam of light required to produce the rings being
inversely proportional to the number of colloidal
particles in the solution. Thus, a large beam of light is
needed for distilled. water, whilst with a good colloidal
solution so small a beam as to be scarcely visible will
produce vivid colours with selenite.

1 Proc. Roy. Soc. Lond., 1868, 17, 223 ; Phil. Mag., 1869, (4), 37,
384-388,

62 USE OF COLLOIDS IN HEALTH & DISEASE

A true solution devoid of all colloidal particles does
not show the Tyndall effect, though it is extremely
difficult to obtain any liquid which does not give at
least a faint indication. Fluorescent solutions (such

j

T?

^_

0

, 4

'K I

0

1 i
1 1

1 H=|

4--------J

jT] i<

fes

1

l£J A\

i! i

/"

FIG. 4. TYNDALLMETER (Vertical Section and Plan).

as quinine disulphate, dilute eosin solution, etc.) which
might otherwise be mistaken for colloidal sols, do not
show this effect.

A convenient arrangement for applying the Tyndall
beam to colloidal liquids is that devised by Tolman
and Vliet. It consists of an electric light bulb B, a

THE TYNDALL PHENOMENON 63

condensing lens L, giving a beam of parallel light which
passes through the diaphragm D, and a Macbeth illu-
minator for measuring the intensity of the Tyndall
beam T. A cylindrical tube is introduced at T through
which the liquid to be examined is admitted and dis-
charged. The tubes Ax and A2 are provided to absorb
the beam after it has passed through the colloidal
liquid, and also to serve as a dark ground on which to
view the Tyndall beam. The central chamber in which
the colloid to be examined is placed is about i in.
diameter and 4 in. long, and the tubes Ax and A2 are
about the same diameter and 12 in. long. The illumi-
nator is an electric lamp of about 3O-candle power at 6
to 8 volts, capable of adjustment so that the apparatus
may be standardised, the light being usually ad-
justed so as to give a brightness of 22-5 foot candles,
though any convenient figure may be used. The in-
tensity of the Tyndall beam is fairly proportional to
the concentration of the colloid when the dispersion
is great, but when the concentration is much higher
than 0-5 gm. per litre the intensity is not proportional
as the increased turpidity of the sol prevents the light
passing through the liquid. It should be noted that
the size of the particles must be taken into account, as
in the following formulae :

T=knd* for small particles
T—klnd6 for large particles

where T is the intensity of the beam, k and kl are
constants ; n is the number of particles per cb. cm.,
and d is the diameter of the particles.

(c) The Gold number is a measure of the protective

64 USE OF COLLOIDS IN HEALTH & DISEASE

power of a colloid against the tendency of other colloids,
etc., to effect precipitation ; it is also a measure of the
stability of the colloidal sol. The gold number is
defined by Zsigmondy1 as the weight in mgms. of
colloid which just fails to prevent the change from
red to violet in 10 cc. of gold solution (containing
0-0053 to 0-0058 per cent of gold) when i cc. of 10
per cent solution of sodium chloride is added to the
sol. Hence, the lower the gold number the greater the
protective effect of the colloid or the greater the
stability of the sol examined.

The gold number is found as follows : Three portions,
a, b, and c, containing 0*01, o-i and I cc. of a suitable
protecting colloid such as gelatin and i cc. of the colloid
to be tested, are placed in three small beakers and well
mixed with 10 cc. of gold collosol. After three minutes
i cc. of 10 per cent solution of sodium chloride is added
to each and mixed. Assuming there is a colour change
in a but not in b the gold number lies between o-oi and
o-i. For a more accurate determination, repeat with a
fresh series, using 0-02, 0-05, and 0-07 cc. of colloid.
The following gold numbers are useful :

Class of protective
colloid.

Gelatin and glues . . . 0-005-0-010

Isinglass 0-010-0-020

I

Casein o-oio

Good gum arabic . . . 0-150-0-250 II

Dextrin 6-000-20-000 1 -QJ

Potato starch . (about) 25-000

Silicic acid oo IV

The stability number is a useful modification of the
test, as applied to the determination of the stability

1 Zeits. anal. Chem., 1902, 40, 697.

ASSAYING COLLOIDAL SOLS 65

of a colloidal sol. It is found by first selecting a sub-
stance which will decompose the colloidal sol, preparing
a suitable solution of this substance, and then adding
it to a known volume of the sol to be examined. The
amount of substance required to just destroy the
activity of I c.c. of the colloidal sol, as observable
under the ultra-microscope, is the stability number.

(d) The time required before a colloidal sol will form
a deposit is a crude, but useful, measure of its stability.
With sols of poor quality the time is very short, but
properly stabilised sols are remarkably durable. The
author kept a sample of colloidal iodine dispersed in
33 times its weight of mineral oil for three years and
found that it was as active and free from deposit as
when first prepared. Great care is needed when making
comparisons of colloids on a time basis, as so many
variable factors may occur. The influence of heat
and light must not be overlooked, whilst even more
important may be the effect of traces of material dis-
solved out of the glass of which the vessel containing
the colloid is composed. Traces of dust or organic
matter in the vessel used may have a serious effect,
and for this reason colloidal sols should not be stored
in corked bottles. If proper care is taken to stabilise
the sols, those used remedially can be stored indefi-
nitely in ordinary glass-stoppered bottles as the
stabilising agents which prevent the decomposition
of the sols by silicates or alkalies dissolved from the
glass do not affect the physiological activity of the
colloids.

(e) The effect of serum or other physiological fluids
on a sol intended for medical or surgical purposes

66 USE OF COLLOIDS IN HEALTH & DISEASE

should be fully investigated before employing the sol.
Unless this is done, sols may be used which are quite
useless owing to their premature decomposition. This
applies particularly to " home-made " preparations ;
those bought from reliable manufacturers have usually
been investigated by independent authorities and their
suitability can be ascertained by enquiry. Speaking
broadly, pure suspensions of a colloid in water are
quite useless physiologically and pathologically, as
they are decomposed immediately they enter the blood
stream. By preparing them in a suitable manner with
the proper stabilising agent in each case, this objection
may be completely overcome.

CHAPTER VIII

COLLOIDS AS GERMICIDES AND DISINFECTANTS

IT has long been the desire of physicians and sanitarians
to find a series of substances which will destroy disease-
producing germs and yet prove harmless to human
beings or even to domestic birds and animals. Many
attempts have been made to obtain compounds
analogous to carbolic acid, with a high germicidal and
low toxic power, but only a meagre degree of success
has been reached. This is only to be expected when
it is realised that the human organism is composed of
an indefinite number of cells and that any substance
which kills bacteria or other disease-producing
organisms is almost certain to have a similar action
on these cells. The difference in action is merely one
of degree, and is therefore subject to limitations and
accompanied by risks which are far from satisfactory.

Moreover, some of the most virulent germs are able
to flourish in solutions of carbolic acid (phenol) and
other well-known disinfectants of a strength which
would be poisonous to human beings, and also the
evolution of germs of one kind into those of another
renders almost chimerical the search for a general germ-
poison which is non-toxic to human beings.

Fortunately, the recognition of bacteria and their
products as essentially colloidal in character has greatly
facilitated the study of disinfection. It is now realised

67

68 USE OF COLLOIDS IN HEALTH & DISEASE

that — disregarding the fact that bacteria are alive —
they may — owing to their colloidal character and that
of the toxins and some other substances they pro-
duce— be destroyed by substances which bear an
electrical charge opposite to that of the bacteria or
their colloidal products. The effect of an ordinary
disinfectant on bacteria is the result of its adsorption
by the latter, forming either a chemical compound, as
appears to be the case with formalin, or a distribution
of various phases in accordance with the well-known
law of adsorption of colloids. In the latter case,
colloids of opposite electric charge will precipitate
each other so long as neither is in great excess, but if
either colloid is in excess both will be rendered inactive
though no precipitation may occur.

The great advantage of dealing with germs as colloids
lies in the fact that the agents used for their coagula-
tion and consequent destruction are not necessarily
poisonous — an advantage which becomes of utmost im-
portance when it is desired to destroy the bacteria in
corpore villi. In other cases, where the use of phenol
and other poisonous substances is less objectionable,
their lower cost may rightly be taken into considera-
tion. Some of the most fruitful results in this line of
research are those which have followed the discovery
by the late Henry Crookes in 1910 that certain metals
when in a colloidal state have a highly germicidal
action, but are quite harmless to human beings. It
was previously known that certain finely divided
metals had a feeble toxic action on the lower forms of
plant life, and that the germicidal power of certain
metallic salts depends to a very large extent on the

GERMICIDES AND DISINFECTANTS 69

degree of ionisation and on the specific properties of
the individual ions, those of the metal having the
chief germicidal power. In other words, the greater
the extent to which the metal is set free in a very
dilute solution of its salts, the greater is the germicidal
power of the solution ! By converting the metal into
the colloidal state it may be applied in a much more
concentrated form and with correspondingly better
results.

The importance of this twofold fact has been largely
obscured, partly by the germicidal properties of some
substances apart from their degree of ionic dissociation,
partly by the manner in which some substances
are adsorbed by the products accompanying the
bacteria, and so are rendered inert before the latter
are affected, and partly because of the ignorance of
the means of preparing colloidal metals in a form
sufficiently stable for administration as medicines.

Equally unfortunate was the death of Mr. Crookes
before he had been able to extend the results of his
discovery, though these difficulties and drawbacks
have now been overcome and are chiefly of historical
interest. It is now definitely known that the germi-
cidal properties of certain colloidal metals are based
partly on the chemical action of the metals themselves,
different metals having greater specific action on some
bacteria than on others, but chiefly on the fact that
metals are in the colloidal (sol) state.

These colloidal metals — of which gold and silver
are the best known — consist of such minute particles
that the latter have ample space for an extremely
active movement without touching one another.

70 USE OF COLLOIDS IN HEALTH & DISEASE

Moreover, by virtue of a property well known in
physics — the particles having a like electric charge
tend to repel one another and thus increase the
stability of the liquid. When such metallic particles
are added to a fluid containing in solution, suspension,
or in that intermediate state we recognise as colloidal,
particles bearing the opposite electrical charge — or in
some cases if the particles are neutral — coagulation
or precipitation rapidly occurs.

The germicidal action of colloidal metals, such as
silver and mercury, at a concentration of i : 20,000
is clearly shown by the following test made by the
late Henry Crookes :—

Silver and mercury " Collosols " of the normal
strength (i in 2000) were diluted with 9 times their
quantity of nutrient broth (i in 20,000), and 10 cc. of
this mixture were infected with two loopfuls of a
vigorous culture of B. coli communis ; after shaking,
so as to mix thoroughly, streak cultures were made
quickly on agar plates, the first within ten seconds,
then at two, four, six, eight, and ten minute intervals.
These plates were incubated at 37° C. for forty-eight
hours, and gave the following results :—

Silver " Collosol " (i in 20,000) Mercury " Collosol " (i in 20,000)

with B. coli communis with B. coli communis

After 10 seconds — Growth After 10 seconds — Growth
2 minutes „ ,,2 minutes — No growth

4 » » » 4 » »

>, 6 ,, No growth ,, 6 „ „

» o ,, ,, ,, o ,, ,,

„ 10 „ „ „ 10

In each case the blank or control streak gave a vigorous
growth.

GERMICIDES AND DISINFECTANTS 71

These experiments were repeated with silver and
mercury " Collosols " at the normal strength of one
part in two thousand. In every case, B. coli communis
was killed within ten seconds, the only growths on the
agar plates being those of the untreated control
streaks. Several comparative tests were made with
the gonococcus grown on agar plates smeared with
fresh blood, with the usual precautions. A plate
showing a vigorous growth and answering to the
typical tests (viz. Gram-negative, no growth on
gelatin or agar at 20° C. without fresh blood, but
vigorous growth at 37° C. on agar with fresh blood,
and displaying the well-known diplococcus in pus cells)
was swabbed with " Collosol " silver for two minutes,
after which time streak cultures were taken and
transplanted to agar plates smeared with fresh blood
as before, at intervals of two, four, six, eight, and ten
minutes, and incubated in the usual way at 37° C.
Result. — No growth whatever.

Many series of experiments similar to this gave
similar results ; for instance, a young vigorous growth
of B. tuber colosis was killed by " Collosol " silver
(l in 2000) in four minutes. Staphylococcus pyogenes,
various Streptococci, and other pathogenic organisms,
are all killed in three or four minutes ; in fact, no
microbe is known that is not killed by this colloid in
laboratory experiments in six minutes.

The following experiments were made by W. J.
Simpson, C.M.G., M.D., etc., Professor of Hygiene,
King's College, London, and R. Tanner Hewlett, M.D.
(Lond.), F.R.C.P. (Lond.), Professor of Bacteriology in
the University of London, were printed in the

72 USE OF COLLOIDS IN HEALTH & DISEASE

Lancet of 12 December, 1914, and are of special
interest.

Drs. Simpson and Hewlett mixed Silver Collosol
solution with nutrient broth in various dilutions,
taking 10 cc. of each in a tube. These were inoculated
with one drop of 24-hour broth culture of the typhoid
bacillus, incubated, and subcultures made after vary-
ing times. For the sake of comparison, similar experi-
ments were carried out with corrosive sublimate
under the same conditions. The results were as shown
in the tables :

WITH COLLOSOL

500 per million

zoo „ ,,

50 „

25 „

10 „

5 „

15 min.

Subcultures made after

30 min. i hour 2 hours

O O

Original
tubes after
24 hours 3 days

WITH CORROSIVE Subcultures made after
SUBLIMATE 15 min. 30 min. i hour 2 hrs. 24 hrs.

Original
tubes after
3 days

500 per million . +

0000

0

100 ,, ,, +

0000

O

50 „ . +

+ 000

0

25 „ . +

+ o o o

0

10 „ ,, +

+ + + +

0

5 » „ • +

+ + + o

0

+ = growth ; o =no growth in the subcultures.

A comparison revealing such a small difference in
germicidal power between the collosol and corrosive
sublimate, considered in the light of the absolute
non-toxicity of the collosol, is surely remarkable and
cannot fail to evoke considerable interest.

Many other experiments of a similar nature have

GERMICIDES AND DISINFECTANTS 73

been made by chemists and medical men, all testifying
to the value of " Collosols " as bactericides.

On the 2Oth May, 1913, two plates of nutrient
gelatin were exposed on the window-sill for half an
hour. A had been covered previously with " Collosol
Argentum " for five minutes ; B was untreated. Both
plates were incubated for forty-eight hours at 20° C. ;
after which, A remained sterile whilst B contained
about 350 colonies of microbes. Figs. 5 and 6 illustrate
this preservative effect of " Collosol Argentum."

It might be suggested that a liquid containing only
one part of colloidal metal in 2,000 of fluid would be
too weak to be of use, but this is not the case. There
are at least 20,000 million active particles of metal in
i cc. (=15 drops) of properly prepared colloidal silver of
this concentration, and one great advantage of colloidal
elements in such a low concentration is their complete
harmlessness to the patient.

Not all elements in the colloidal state have a germi-
cidal action. The following table, based on Henry
Crookes' investigations, is interesting in this connec-
tion :

No germicidal action : Gold, platinum, palladium,
rhodium, indium, tantalum, cadium, magnesium, tin,
graphite, selenium, sulphur (sulphur has a strong,
stimulating action).

Slight germicidal action : Bismuth, lead, aluminium,
zinc, copper.

Strong germicidal action: Thorium, cobalt, silver,
mercury, antimony, mercuric cyanide, mercuric
chloride, arsenious acid.

The germicidal action of metals and some other

74 USE OF COLLOIDS IN HEALTH & DISEASE

substances is clearly shown in Figs. 5 to 18, which are
reproduced from photographs taken by Hy. Crookes
of Petri dishes containing fish-agar, or other nutrient
medium inoculated with various bacteria and kept
under conditions favourable for their incubation and
development. In the centre of each dish was placed a
piece of the substance whose action was to be examined
and its effect is clearly shown.

On examining the illustrations showing a dish con-
taining a germicidal metal it will be seen that sur-
rounding the latter is a vacant space in which no
bacteria have grown, around it is a dense ring in which
the germs have flourished to an abnormal degree, and
between this ring and the circumference of the dish is
practically the same as though no germicide were
present. The cause of this arrangement — which is
particularly marked in the case of silver (Fig. 10) — is
the germicidal action of the minute amount of colloidal
silver which has been formed immediately around the
metal, whilst further away a still smaller proportion
of the colloidal silver has a stimulating action on the
bacteria. Still further away there is no colloidal silver,
and the bacteria grow in the normal manner. The
growth of the same bacteria in the presence of a
germicidal and inert colloidal metal may be compared
by observing the differences between Figs. 5, 6 and
10 ; the former, which shows the action of colloidal
silver, exhibits the characteristic features very clearly ;
in the latter, which shows the result of using non-
germicidal colloidal gold, these features are absent and
the bacterial growth is fairly uniform.

The amount of colloidal metal produced under the

II

N O

I*

.2

00
tJ3

fl

El

^ U

c .
.2 ffi

fr -

GERMICIDES AND DISINFECTANTS 75

foregoing experiments is almost infinitesimal, so that
its germicidal effect is very striking. Much more
impressive results are obtained by the addition of a
properly prepared colloidal solution to an inoculated
medium — the bacteria then being destroyed quite
rapidly — but the reproduced photographs show in an
unmistakably clear manner the great potentialities
of colloidal metals even under conditions which are
not particularly favourable to their use. It has been
estimated that in the death zone, where the concentra-
tion of the colloidal metal is greatest, the latter does not
exceed twenty-five parts per million parts of nutrient
medium.

The germicidal action of certain metals in the
colloidal state having been demonstrated, it only
remained to apply them to the human subject, and
this has been done in a large number of cases with
astonishingly successful results. It is not suggested
that colloidal metal sols should replace the customary
disinfectants for sterilising excreta, vessels of various
kinds and for other general purposes, but for internal
administration, either orally or hypodermically, they
have the advantage of being rapidly fatal to the para-
sites— both bacterial and otherwise — without any toxic
action on the host.

CHAPTER IX

TYPICAL COLLOIDAL REMEDIES AND THEIR USES

TURNING now to the use of colloidal liquids in the
relief or cure of disease, it is important to realise the
simple character of the active agents in many such
liquids. In the majority of the most successful
remedies definitely used on account of their colloidal
properties, the active agent is a metal, such as silver,
mercury, or palladium, or a non-metal element, such
as iodine or sulphur. More complex substances, such
as quinine and cocaine, have also been used success-
fully in the colloidal state, but not nearly to the same
extent as the elements just mentioned. The reason is
quite simple ; with only a limited number of investi-
gators it is impossible to proceed as rapidly as may be
desirable, and the remarkable results which have
followed the use of elements in the colloidal state has
naturally resulted in attention being concentrated on
these elements.

A great advantage which colloidal sols of elements
possess over compounds is the facility with which their
action may be studied. If a salt or other compound is
administered there is always the chance of it under-
going hydrolysis or ionisation in the blood stream or
alimentary canal, thereby setting up complex reactions
in which elements other than the one under investiga-
tion are involved. For example, iron may be adminis-

76

COLLOIDAL REMEDIES AND THEIR USES 77

tered in the form of a carbonate which is converted
in the stomach into chloride, and this, on dilution, is
hydrolysed so that eventually there are formed both
hydroxide and chloride of iron. If the iron were
administered as an element, these complications would
be avoided, and the investigator would be much more
certain in drawing conclusions. Except in the colloidal
form, it is impossible to administer elements in an
active state apart from other elements necessary to
bring them into solution, for no method of grinding
has been discovered which will reduce the elements to
so fine a state that they will remain in suspension in
water for months without any tendency to deposition.
The coarser product obtained by the most elaborate
process of trituration is devoid of those properties
which give colloidal sols their therapeutic value.

The effect of the administration of certain elements
in a colloidal state to persons suffering from certain
pathological conditions is extremely interesting, partly
on account of the progress of the recovery, and partly
on account of the absence of complications such as
occur when the same element is administered in
another form. For example, iodine and mercury, as
ordinarily used, are both unsatisfactory on account
of their great toxic action. This is almost wholly
avoided when these elements are administered in the
form of colloidal sols. The remarkable fact that
colloidal silver and iodine do not stain the skin, whereas
the pharmaceutical preparations of silver and iodine
do so strongly, is a further indication of the striking
difference between colloidal sols and ordinary solutions.

Widely as colloidal metal sols differ from the same

78 USE OF COLLOIDS IN HEALTH & DISEASE

metals as usually known and from their salts, such sols
have a remarkably close resemblance to enzymes in
their action on physiological products. The activity
of both is greatly increased in alkaline solution up to a
maximum which is followed by a reduction in activity
with further increase in alkalinity.

There is also a striking parallelism between the
poisoning action of various substances (prussic acid,
hydrogen sulphide, and mercuric chloride) on a metal
sol and on an enzyme (p. 42).

Recent researches on the action of various glands
have also shown that the fluids they excrete are not
only colloidal in character, but that in several instances
they contain, as an essential constituent, some element
which is not usually considered as an integral part of
the organism. Thus, the dependence of the thyroid
fluid on its iodine content has only been established
within the past four years. In a similar manner the
minute quantities of sulphur, phosphorus, and iron
which are present in the animal organism are not
adventitious. They play definite parts, and their
absence or diminution results in a serious disturbance
of function. Insufficient iodine in the thyroid gland
induces cretinism and analogous diseases, an in-
sufficiency of phosphorus accounts for certain nervous
disorders, too little iron in the blood results in anaemia,
and deprivation of sulphur is characteristic of rheu-
matic subjects.

The intense power of reaction possessed by ele-
mentary sols is very striking. They can induce
chemical reactions to occur which would otherwise
require conditions of temperature and pressure quite

COLLOIDAL REMEDIES AND THEIR USES 79

unattainable in the human subject. Thus, metal sols
have a catalytic action as powerful as platinum black,
and can effect such changes as the union of hydrogen
and oxygen in the cold, the oxidation of hydriodic acid
by oxygen in solution, and the decomposition of
hydrogen dioxide.

The activity of some metal sols is so great as to be
barely conceivable. Thus, platinum sol has marked
catalytic properties when only 0-0000002 grain of the
metal is present ! This intense power of promoting
reactions among other substances and of being them-
selves left free at the end of the reaction results in
very small quantities of metal sols being capable of
effecting changes which are wholly disproportionate
to the amount of sol present. It also explains why
changes which are of an extremely complex character
when a catalyst is absent may be effected readily in
the presence of an elemental sol, and, further, that the
administration of such a sol will produce results in a
short time which would require a long period if effected
by means of a long series of successive reactions.
Metal sols have the further therapeutic advantage of
acting most rapidly in faintly alkaline solutions, so that
when properly prepared they are not affected adversely
by normal blood.

Before a drug can exert its full therapeutic action it
must be converted into the ionised or into the colloidal
state. Unfortunately, an element in the ionised state
is always associated with the corresponding ions of the
salt from which it was produced. Thus, mercuric
chloride, when ionised, is separated into mercury ions
and chlorine ions, and the net electric charge of the

80 USE OF COLLOIDS IN HEALTH & DISEASE

system is neutralised. When an element such as
mercury is administered in the colloidal state, however,
it, and it alone, is introduced as an active agent, the
charge on the particles is quite definite and their
activity is correspondingly great. Consequently, there
is much truth in the statement that a drug to be fully
efficient must be in a colloidal state, or convertible
into it in the body of the subject.

The conversion of a colloid into the form required
by the organism is most rapid when the sol is injected
intramuscularly, but there is less pain and equally
good (though slower) results by intravenous injections,
and in many cases by oral administration.

The use of specific sols in medicine is no universal
" cure all," but just as the administration of pure
chemicals, such as quinine hydrochloride, marked a
great advance over the use of a crude tincture of
cinchona bark, so the employment of certain elements
in the form of sols marks a still further line of progress
in the conquest of disease.

Taking the chief colloidal sols which have been
used medicinally, we may first mention several metal
sols :

Colloidal gold was first prepared in a sufficiently pure
state for effective examination by Faraday in 1857,
but it was known in the Middle Ages, though its most
important properties were not realised. As early as
1885, it was largely in use in the United States as the
basis of a cure for dipsomania, but even then it was
only one of a number of ingredients of a complex
mixture whose manufacturer does not appear to have
known much about the properties of the gold in his

COLLOIDAL REMEDIES AND THEIR USES 81

preparation, notwithstanding the statements in the
advertisements of that day.

Colloidal gold is characterised by the great differ-
ence in its colour when it is prepared by different
methods. As ordinarily prepared by reducing a
slightly alkaline solution of gold chloride with formal-
dehyde or phosphorus, it is an intensely red liquid, the
particles of which are negatively charged, but by the
addition of suitable electrolytes (aluminium salts), it
is also possible to produce a blue solution with posi-
tively charged particles. A colourless gold sol is
produced if the electric field is too strongly negative
or positive. Experiments by Garnet l on the refractive
indices of colloidal sols of gold, silver, and copper show
that the metal in each case is in suspension in the form
of extremely minute spheres and that the different
colours of gold sols are due to the particles of metal
and not to any inherent differences in the nature of the
dispersed particles.2

Colloidal gold sol is tasteless and non-poisonous, but
the metal is readily precipitated by bases and salts,
so that it is not easy to administer it satisfactorily.
Moreover, the germicidal action of gold is very feeble
(p. 73), so that its use in therapeutics is negligible.
On the other hand, it is so easily prepared and is so
highly sensitive that gold sol is chiefly used as a
standard with which others may be compared.

1 Phil. Trans., (A) 203, 1904, 385 ; and 205, 1906, 237.

z According to T. Sherrer (Engineering, 1919, 488), colloidal gold
and silver hydrosols, when examined by X-rays, show interference
bands characteristic of crystalline solutions ; the interference bands
of the hydrosols of silica and stannic acid show that these substances
are sometimes crystalline and sometimes amorphous. Colloidal
albumen, casein, starch, and cellulose appear to be always amorphous.
G

82 USE OF COLLOIDS IN HEALTH & DISEASE

Colloidal silver, containing 0-05 per cent of the
metal in a colloidal form and not as a salt, is a clear
cherry red liquid which possesses a marked oxidising
action in addition to its power of coagulating colloids
of opposite electric sign.

The colour of the pure silver sol is largely dependent
on the manner of its preparation and the presence or
absence of minute quantities of electrolytes. Even
the glass of the vessel in which the sol is prepared may
affect the colour by yielding traces of soda, silica, or
other oxide to the sol. When prepared under suitable
conditions and properly " protected," colloidal silver
sol is quite stable even in the presence of salts and of
the normal constituents of the blood. Its destructive
action on toxins is very marked, so that it will protect
rabbits from ten times the lethal dose of tetanic or
diphtheric toxin. Colloidal silver is prepared in the
following forms to meet clinical requirements :

(a) Aqueous solution, in bottles or ampoules.

(b) Pasta, in glyco-gelatin base.

(c) Ointment in lanoline base.

(d) Suppositories and pessaries.

Unlike certain organic compounds of silver, the
colloidal metal is not organotropic and does not cause
necrosis of the underlying tissues. Hence, it has been
used for several months consecutively without staining
the conjunctiva.1

Taken internally, the particles of colloidal silver are
resistant to the action of dilute acids and alkalies of
the stomach, and consequently continue their catalytic
action and pass into the intestine unchanged. The

* Brit. Med. Jaurn., Jan. 15, 1915.

COLLOIDAL REMEDIES AND THEIR USES 83

importance of this is obvious in such conditions as
ulcerative urticaria and other forms of dermatitis sug-
gestive of toxaemia,1 bacillary dysentery, diarrhoea, and
colitis.

The use of collosol argentum in ophthalmic practice2
and in the affections of the ear and in nasal catarrh3
and its clinical effect by intravenous injection in
septicaemia are reported in the medical journals.4

Colloidal silver has been used with marked success
in the following cases, cited by C. E. A. MacLeod5 :

Septic and follicular tonsilitis, Vincent's angina,
phlyctenular conjunctivitis, gonorrhceal conjunctivitis,
spring catarrh, impetigo (contagious acne of face and
body), septic ulcers of legs, ringworm of body, tinea
versicolor, soft sores, suppurative appendicitis after
operation (the wounds cleaned rapidly), pustular
eczema of scalp and pubes, chronic eczema of meatus
of ear with recurrent boils, and also chronic eczema of
anterior nares, offensive discharge in case of chronic
suppuration in otitis media, bromidrosis of feet, axillae
and blind boils of neck. By injection : gonorrhoea
and chronic cystitis (local), boils, epiditymitis.

Sir James Cantlie6 has found it particularly effective
in cases of sprue, dysentery, and intestinal troubles.
Being non-toxic, the dose can be increased from i to 2
or more drachms twice or thrice daily.

A. Legge Roe regards stable colloidal silver as a
most useful preparation7 in ophthalmic practice, and
particularly in cases of gonorrhceal ophthalmia, puru-

1 Brit. Med. J., May 12, 1917. • Lancet, Feb. 3, 1912.

2 Brit. Med. J., Jan. 15, 1917. 8 Brit. Med. J., Nov. 15,1913.
8 Brit. Med. J., Dec. 15, 1917. 7 Brit. Med.J., Jan. 16, 1915.
* Lancet, Feb. 16, 1918.

84 USE OF COLLOIDS IN HEALTH & DISEASE

lent ophthalmia of infants, infected ulcers of the cornea
and hypopyon ulcer (tapping of the interior chamber
and cautery, and other operative procedures being now
rarely required, whilst if perforation does occur it is
smaller and more manageable), interstitial keratitis,
blepharitis, dacryocystitis, and burns and other wounds
of the cornea. According to this authority, the great
chemosis which usually accompanies the use of silver
nitrate is avoided and, in his opinion, if colloidal silver
were adopted in every case of purulent ophthalmia
of infants " there would be no such thing as impaired
sight or blindness from this cause." He has had many
cases of interstitial keratitis in adults, in which the
complete opacity of the cornea has become absolutely
clear in from three to five months, and anyone who has
had much experience of this disease in adults knows
how often permanent impairment of sight results, and
how long the treatment used to last, especially if
irritants had been used prior to colloidal treatment
The eye is kept under atropine or preferably scopola-
mine, and the colloidal sol is dropped in three times a
day, the eye being kept closed afterwards for five
minutes. When all active symptoms have disappeared,
and not until then if any opacity remains, yellow oxide
or mercury ointment may be used ; but, if treated
throughout as described above, this will rarely be neces-
sary. In dacyocystitis, Dr. Roe recommends that
" after probing, the sac should first be syringed out
with saline solution and, after expressing any that
remains, the sac should be filled with colloidal silver
with the syringe. In cases of long standing this will
not be sufficient ; the sac should be incised and plugged

COLLOIDAL REMEDIES AND THEIR USES 85

with ribbon gauze, and for about a week the sac should
be dressed daily by inserting it into ribbon gauze
soaked in 10 per cent solution of potassium bichromate,
or the lining membrane of the sac should be scraped.
The wound is then allowed to close and the collosol
injections continued."

T. H. Anderson Wells1 used it intravenously in a
case of puerperal septicaemia without any irritation of
the kidneys and with no pigmentation of the skin.
This physician has found that a series of intravenous
injections, each of collosol argentum, every forty-eight
hours produce no untoward effects and that recovery
is rapid.

Sir Malcolm Morris2 has found that colloidal silver
is free from the drawbacks of other preparations of
silver, viz. the pain caused and the discoloration of
the skin ; indeed, instead of producing irritation it
has a distinctly soothing effect. It rapidly subdues
inflammation and promotes the healing of the lesions.
He has had remarkable results in enlarged prostate
with irritation of the bladder, in pruritis ani and
perineal eczema, and in haemorrhoids. It can be used
in the form of suppositories whilst a solution is simul-
taneously applied to the irritated skin. In bromidrosis
in the axillae and feet it quickly gives relief. It causes
a rapid disappearance of warts. Being non-toxic, it
can be given internally in urticaria and other forms of
dermatitis which are suggestive of toxaemia. In such
cases, it is quickly beneficial.

In ophthalmology, colloidal silver has now largely
replaced silver nitrate.

1 Lancet, Feb. 16, 1918. 2 Brit. Med. J., May 12, 1917.

86 USE OF COLLOIDS IN HEALTH & DISEASE

J. Mark Ho veil1 has found colloidal silver beneficial
for permanently restoring the potency of the Eusta-
chian tubes and for reducing nasopharyngeal catarrh.

Colloidal silver has also been used successfully in
septic conditions of the mouth (including pyorrhoea
alveolaris — Rigg's disease), throat (including tonsilitis
and quinsies), ear (including Menier's symptoms and
closure to Valsava's inflation), and in generalised septi-
caemia, leucorrhcea, cystitis, whooping-cough, and
shingles.

A preparation of colloidal silver which is opaque to
X-rays has proved invaluable in certain diagnoses.

J. MacMunn 2 has successfully used silver sol in cases
of gonorrhceal prostatic gleet by injecting through an
endoscope into the substance of the prostate gland.

Collosol argentum has also proved useful in influenza,
both as a prophylactic and for curative purposes when
applied as a spray to the nostrils, for bathing the eyes,
and as a gargle for the throat.

B. Seymour Jones has used an intranasal spray of
colloidal silver in a case of cerebro-spinal meningitis.
He has also used colloidal silver with marked advan-
tage in several cases of rhinitis and cedematous en-
largement of the posterior ends of the middle and
inferior turbinates without true hyperplasia.

Colloidal mercury is quite free from the serious objec-
tions to the less soluble mercury salts — such as calomel
—the delayed and irregular absorption with conse-
quent undesirable results of other preparations and,
unlike the soluble mercury salts, it is only feebly toxic.

1 Brit. Med. Journ., Dec. 15, 1917.
1 Brit. Med. Journ., 1917, I, 685.

al

§ 8

« §

S u

COLLOIDAL REMEDIES AND THEIR USES 87

With colloidal mercury, the diffusion is extremely rapid
and chemical affinity low. Hence, the toxicity of col-
loidal mercury (1-2000) is so low that doses of two
teaspoonfuls may be taken twice daily or intravenous
injections of 30 cc. may be given with impunity.

Intravenous injections of colloidal mercury are pain-
less, and this absence of pain is usual in the adminis-
tration of colloidal preparations, and is due to their
isomorphism with the colloidal lipoid and protein of
the tissues and body fluids. Before the introduction
of the arseno-benzene products, the routine treatment
for syphilis was mercury and iodides, and undoubtedly
many permanent and excellent results were obtained.

In late syphilis, iodine is more effective than mercury,
and, conversely, mercury is more effective than iodine in
early syphilis. According to J. E. R. McDonagh,1 this is
due to the fact that mercury acts as an oxidising agent
and that the process of oxidation is more effective in the
early stages of syphilis in producing the death of the
causal organism, whilst as a reducing agent it is more
effective in the later stages. In most cases, the alter-
nate injection of colloidal iodine and mercury is more
effective than if either be given continuously. Accord-
ing to J. E. R. McDonagh,2 the first effect of injecting
a suitable colloid is to break large protein particles into
small ones and thus increase their activity by enlarging
their surface area. In syphilis, there are many large
particles to be broken up, hence the value of colloid
sols. The injection of colloid sols also affects the state
of oxidation or reduction of the system in which it is
introduced, metallic sols increasing the oxidation and

1 Prescriber, June, 1919, 118-120. * Brit. Med. J.t 1917, I. 648,

88 USE OF COLLOIDS IN HEALTH & DISEASE

non-metallic sols the reduction. Colloidal mercury has
cured persistent relapsing malaria in a few days.1

Colloidal iron is the least irritating of all forms of
iron, yet, according to Lyn Dimond,2 it kills within six
minutes such organisms as B.typhosus, B. coli communis,
and various pyogenic cocci. The iron sol seems to have
a definite elective bactericidal action upon such catarrh-
causing organisms as the pneumococcus and various
strains of the Micrococcus catarrhalis. Rapid relief
follows the topical application of colloidal iron in cases
of catarrh of the nose, larynx, or pharynx.

It is also used by subcutaneous, intramuscular and
intravenous injection in cases of extreme chlorosis,
anaemia, erysipelas, and cellulitis.

Iron is almost the only metal found in the animal
organism which is also obtainable in a colloid state in
the presence of water. The significance of the fact has
not been sufficiently recognised. In the serum, the iron
is probably present as a protein compound, the precise
constitution of which has not been determined. Some
authorities consider that the whole of the iron exists
in the form of haemoglobin. The total iron content
of the normal body does not exceed thirty-seven grains,
and although several organic compounds of iron have
been recommended they are by no means satisfactory,
being either too feeble in action or too readily decom-
posed in corpore and so rendered useless. Inorganic
iron is held by many practitioners to be most efficient
in the only true test of the value of an iron preparation,
i.e. increase of haemoglobin in the blood. Haemoglobin

1 G. Cremonese, Garr, D. Osp., 1918, 39, 427.

2 Lancet. 1913, I, 1585.

COLLOIDAL REMEDIES AND THEIR USES 89

was at one time thought to be a definite compound,
but its adsorption properties seem to show that it is
largely colloid in character and consequently is specially
amenable to the action of another colloid such as iron.
Haemoglobin is electro-positive, and to increase its
amount without disturbing the general characteristics
of the serum any iron compound administered must be
electro-positive when it enters the blood stream. For
this reason, iron compounds (e.g. ferric chloride) which
are electro-negative and act as coagulants should be
avoided. The objection to iron carbonate and
hydroxide lies in the fact that they are usually con-
verted into ferric chloride or analogous compounds by
the gastric juices.

Colloidal iron, on the contrary, not being affected by
these juices, is able to enter the blood stream in a satis-
factory and therapeutically active form. Hence the'
administration of iron in the form of a colloidal sol
appears to be a simple means of increasing the amount
of the protein compound in the serum, as this form of
iron, when administered orally, is rapidly diffused in the
stomach, and yet it is not absorbed in individual
positions. It is found that the amino-acids formed
during the process of digestion are readily able to absorb
into their complex molecule a notable proportion of
iron administered in the colloidal form, and from it
to effect the synthesis of haemoglobin.

Colloidal antimony has been used with remarkable
and surprising results in the treatment of coccogenic
skin disease, including deep abscesses, boils, and deep-
seated impetigo. It has also been successfully used by
intramuscular injection in bilharzia, leishmonnoris,

90 USE OF COLLOIDS IN HEALTH & DISEASE

granulama pupendi, ulcus molle serpiginosum, and in
certain stubborn cases of gonococcal urethritis.

Colloidal antimony has been used in conjunction
with manganese with extremely good results in gono-
coccic infections. In India, it has given very satisfac-
tory results in Kala-azar, its administration in this
disease being accompanied with less risk than that of
arsenic.

Colloidal manganese has been used with remarkable
and surprising results in the treatment of coccogenic
skin disease, including deep abscesses, boils, and deep-
seated impetigo. In superficial impetigo, chronic
seborrhoeic eczema, and acute folliculitis it is of little
value when used alone, but it gives excellent results
when employed in conjunction with intramine. The
rapidity of its action,1 combined with the saving of
dressings, render the use of this form of manganese
very attractive in deep-seated coccogenic lesions. It
is usually injected intramuscularly in amounts of 3 cc.
every few days. In most cases, one injection is suffi-
cient. Indeed, colloidal manganese differs from all
other remedies used in the treatment of boils, insomuch
as it is only occasionally that fresh boils make their
appearance during the treatment, and these quickly
subside without further trouble.

E. W. Kirk2 and Dr. W. Habgood3 found colloidal
manganese so good as to convince them that it should
have a wider use in furunculosis and seborrhoeic eczema
following wound infection, and W. E. Levinson4 has

1 J. E. R. McDonagh, Medical Press and Circular, Dec. 5, 1917;
Sir Malcolm Morris, Brit. Med. Journ., April 26, 1918.

2 Brit. Med. Journ., 1918, II, 377. 3 Brit. Med. Journ., II, 76.
* Brit. Med. Journ., 1918, II, 160.

I

^

=

I *
8

s

COLLOIDAL REMEDIES AND THEIR USES 91

confirmed Sir Malcolm Morris's1 recommendation of
colloidal manganese for boils.

J. E. R. McDonagh2 has also used intravenous injec-
tions of 33 cc. of colloidal manganese with excellent
results in cases of poisoning by sulphur compounds,
including mustard gas (dichlorethyl sulphide). Three
typical cases reported by Sir Malcolm Morris are, in his
opinion, so remarkable as to demand publication. At
first the collosol manganese (Crookes) was used in the
form of a single solution. Afterwards it was employed
in the improved form of two solutions, which were
mixed in the syringe ; of this, much smaller doses
(about one-half) suffice.

CASE I

" The patient, a medical man, came to me on Novem-
ber 24th, 1917, with large, deep-seated boils on the
hairy part of the face, which he believed to be an
infection from a carbuncle in a diabetic patient, from
whom he had contracted a septic whitlow. Culture
showed that the micro-organism was the Staphylococcus
pyogenes aureus, and an autogenous vaccine was pre-
pared, with which he was inoculated on November 3Oth.
By this time a boil on the right cheek had enlarged to
the size of a Tangerine orange ; there was much cedema
of the face and eyelids and great pain. On December
6th pus was discharged and the pain relieved ; but
during the next seven weeks boils continued to appear
at intervals, usually in groups of four or five, on one
or both sides of the face. By January I4th, eleven in-
jections of vaccine had been given, antiseptic lotions

1 Brit. Med. Journ., 1918, I, 446.

* J. E. R. McDonagh, Medical World, 1918, p. 137.

92 USE OF COLLOIDS IN HEALTH & DISEASE

and ointments being also applied. On January 3ist
the patient consulted me again and I advised the in-
jection of collosol manganese. The first injection was
given the next day. ' Improvement,' to quote from
the patient's own notes, ' began on the third day
afterwards. Subsequent boils, which continued to
appear for a further fourteen days, were not painful,
and many of them aborted without pus formation.' In
all, four injections were given — 1-5 c.cm. on January
3ist, 2-5 c.cm. on February 5th, 3 c.cm. on February
I2th, and i c.cm. on February 28th ; the first and
second in the gluteus, the third and fourth in the flank.
In the first three the old preparation was used ; in the
fourth the new. By March 5th I was able to report
' All clear/ From November 3oth to January 3ist,
while the vaccine was being given, thirty-three carbun-
cular boils appeared ; after the collosol manganese was
begun there were only seven, the last appearing on
February 2Oth, three weeks after this treatment was
begun. The patient's general health also greatly
improved ; he began to feel better within a week of
the first manganese injection."

CASE II

" The patient was an army captain who was subject
to acne. When the first collosol manganese injection
(0-5 c.cm. of the new preparation) was given on March
I3th, he had been in hospital four months with facial
boils and acute impetigo contagiosa of the same region.
During that time he had had vaccine injections, and
various antiseptics had been applied, without result.

COLLOIDAL REMEDIES AND THEIR USES 93

Another manganese injection (0-5 c.cm.) was given on
March i6th, and a third (i c.cm.) on March igth. By
this time all the lesions had cleared up."

CASE III

" I saw the patient, a lady, for the first time on
February i6th. She had extensive follicular impetigo
of the scalp, which began in the preceding October,
and had gradually become more severe. When she
came to me, she complained of great pain from small
multiple deep abscesses. There was a good deal of
oedema, and the posterior cervical glands were enlarged.
On February i8th 1-5 c.cm. of the old collosol man-
ganese solution was injected. By February 22nd the
lesions were beginning to clear up, the pain was nearly
gone, and the general health distinctly better. A
second injection (0-5 c.cm. of the new preparation)
was given, and a third (i c.cm.) three days later. By
this time further improvement was manifest, and the
patient was able to sleep. No further injection was
required, and by March igth recovery was complete,
the only trace of the disease consisting in small bald
areas on the site of the lesions."

Sir Malcolm Morris attaches much importance to
the great improvement in the patient's general health
observable in each case a few days after the first injec-
tion, and the fact that although the injections were
all intramuscular they were followed by no reaction.

D. McFarland Livingstone has used colloidal man-
ganese with great advantage in three cases of gonorr-
hceal ophthalmia. The first was not of great severity,
but the drug was satisfactory. In the second case,

94 USE OF COLLOIDS IN HEALTH & DISEASE

corneal ulceration had set in, but the eye healed
rapidly. The third case was of the most virulent
type, and the effect of colloidal manganese was most
striking. Prior to treatment, both eyelids were greatly
swollen and almost solid ; there was great tenderness
and pain and the surrounding cheek was also red and
swollen. On opening the lids, the cornea was found to
be completely hidden by overlapping folds of cedema-
tous bulbar conjunctiva. There was an abundant dis-
charge of pus. The eye was bathed with warm boric
lotion and argyrol was used every six hours. An in-
jection of colloidal manganese was given intra-mus-
cularly into the buttock. On the second day there was a
slight improvement. On the third day there was slight
pain ; on the fourth day a second injection of i cc. of
colloidal manganese was given, and by the following
morning all pain had ceased, all the swelling of the bulbar
conjunctiva had completely vanished, the oedema had
lessened, and the discharge was considerably reduced.
The cornea was perfectly clear, and the eye was ap-
parently out of danger. After one week from the
first injection, a third and last injection of manganese
was given, and after a further week the eyes had
become normal, except for gumming of the eyelids
after sleep. Dr. Livingstone reports of this case that
" in a fairly wide and long experience in the treatment
of gonorrhceal blenorrhcea it had never been my good
fortune to witness such a dramatic change. No local
measures of which I am acquainted would have brought
about such a satisfactory termination."

It is not suggested that undue importance should
be attached to a single case, however striking, yet it is

g

II

COLLOIDAL REMEDIES AND THEIR USES 95

clear that such a good indication of what may be
expected under similar conditions should not pass
unnoticed.

Colloidal manganese has also been used successfully
in the case of toothache due to abscess.1

Colloidal copper sols are blue, red, orange, or green,
according to the conditions under which they are
prepared, and the agent used to stabilise them.
Thus, if protalbinic acid followed by hydrazine
is used for reducing copper sulphate, the sol is red
or orange, whilst with protalbinic acid and sodium
chloride Paal obtained green copper sols. Copper
has a special action on the liver and is well known
as a fungicide and as restraining the growth of the
lower organisms and embryonic cells. In the form
which has given the best therapeutic results, col-
loidal copper sol is a dichroic liquid, blood red by
transmitted light and muddy red by reflected light,
which contains o-i per cent of copper as cuprous
subhydroxide, protected by a combination of amino-
acids, which per se have a very low physiological action.
The solution is very stable, but should not be exposed
unduly to the action of air or light, and for this reason
the product is issued in hermetically sealed ampoules,
each containing sufficient for one injection.

It appears to be of use in some cases of cancer, and
the dissipation of a nodule in a patient who had
previously been operated on for scirrhus of the right
breast (cancer) is reported. Results are in many cases
satisfactory, particularly in the initial stages of the
growth and in preventing recurrence after operation.

1 D. A. Wood, Brit. Med. Joufn., 1919, 330.

96 USE OF COLLOIDS IN HEALTH & DISEASE

Where pain is present, great relief is obtained by the
intravenous injection of colloidal iodine. If any
streptococcus is present, injections of colloidal man-
ganese should be given alternately with those of copper.
In some cases where an improvement is manifested, but
not maintained, injections of a reducing agent, such as
pallamine (colloidal palladium) or intramine may be
given alternately with copper or manganese, Inj ections
of colloidal copper should always be given intramuscu-
larly, preferably in gluteus medius. The dose is 3 cc.
and the injection is preferably given on the first, fourth,
seventh, and twelfth days and then once a week.
Treatment should be continued until all symptoms have
completely disappeared, after which one injection per
month should be continued for about a year.

The use of colloidal copper injected intravenously
can aggravate boils if administered in large doses ;
in smaller quantities and injected intramuscularly it
has the opposite effect, but is far inferior to colloidal
manganese for this purpose.

In malignant disease the intramuscular injection
of copper has proved beneficial, the metal having
been shown to be present in the growth within twenty-
four hours of the injection. Merchel de Gers and
others1 have stated that colloidal copper exerts
an inhibitive action on all cell-metabolism and it
has been used extensively on the Continent in the
treatment of cancer. In this connection, it is impor-
tant to note that cases of cancer in which copper
can be shown to be present in the growth are certainly
the ones which are most amenable to treatment. The

1 Med. Press, 1912, II, 26 ; 1913, I, 87.

COLLOIDAL REMEDIES AND THEIR USES 97

difficulty lies in causing the copper to penetrate to the
periphery of the cancer.

Pessaries of colloidal copper in glyco-gelatin have
proved serviceable for uterine fibroids.

Luton l refers to the value of the salts of copper in
tuberculosis ; its various forms yield more or less
rapidly to the treatment when begun regularly. The
existence of high fever is regarded as an obstacle to the
treatment.

Colloidal platinum sol has been extensively used in
promoting various chemical reactions. It appears to
be too powerful for use in medicine, but has been
employed to a limited extent for the same diseases as
colloidal silver.

Dr. A. G. Auld has obtained encouraging results with
colloidal platinum in case of pyrexia, e.g. subacute
pleuritis and pneumonic conditions and protracted
paratyphoid fever. He found that colloidal silver
acted even more intensely than the year-old platinum
colloid previously used, and as it is less drastic it is, in
every way, preferable.

Colloid palladium oxide has been applied successfully
in the treatment of obesity by injecting it hypoder-
mically into the fatty areas.2

Colloidal palladium is a reddish liquid of a peculiarly
active character

A. C. King-Turner 3 has used colloidal palladium
(pallamine) with good results in epilepsy, the results
of injecting each patient intramuscularly with 0-5 cc.

1 Prov. Med., Dec., 1912.

8 Brit. Med. Journ., 1918, I, 195.

3 M. Kauffmann, Munch. Media. Wochenschr, 525, 1913.

98 USE OF COLLOIDS IN HEALTH & DISEASE

of " pallamine " at intervals of three days being most
marked and encouraging. To cite three cases : l

" H. G., male, aged forty-five, suffering from epilepsy
and of doubtful traumatic history, had an average of at
least four fits weekly. These fits were of a very violent
nature, the convulsion stage lasting on occasions for
an hour, followed by stupor, confusion, and excitement.
Since the three injections, only one fit has occurred in a
fortnight, and that of a mild nature, lasting only thirty
seconds. The patient feels greatly improved in general
health, is less morose, more conversant, expressing
himself more lucidly, and is very grateful for the
treatment.

M. A. L., female, aged fifty-three, an epileptic of
thirty years' standing, with an average of six fits per
week of a very violent nature. Since injection, three
weeks ago, no fit has occurred, but she has had a few
sensations. She is now very placid, well behaved, and
much better in every way.

M. A., female, aged sixteen, congenital epilepsy.
She had seldom less than three or four fits per day.
Since injection, three weeks ago, only four fits have
occurred. She is much brighter, greatly improved in
general health, and has now great hopes of being dis-
charged from the institution, recovered. In two cases
where manganese sol was injected after pallamine, a
fit resulted, showing that careful selection of the
appropriate metal is necessary."

Like colloidal platinum, pallamine is a very powerful
catalyst, and such strongly combined organic sub-
stances as nitro-benzol, and numerous acids, aldehydes,

1 Brit. Med. Journ., 1918, II, 255.

COLLOIDAL REMEDIES AND THEIR USES 99

ketones, diketones, and nitriles are readily reduced by
passing hydrogen through them, if a little colloidal
palladium is present and the products are kept neutral
by the addition of sodium carbonate.

Sols which are not normal constituents of the body,
e.g. mercury, arsenic, are liable to be toxic, but mercury
is less toxic than arsenic, as it has less affinity for nerve
tissue, and the colloidal preparations are quite unlikely
to be dangerous in the hands of medical men. It is,
of course, important that they should be prescribed
with due care as, otherwise, oxidation may occur where
reduction is desired, or vice versa, but the risk of
serious results to the patients is far less than when
certain crystalloid remedies or tinctures, etc., are used.

Colloidal nickel has been used in meningitis.

Of the non-metal elements, the most widely used are
iodine and sulphur.

Colloidal iodine may be obtained in four forms:
(i) aqueous, and (ii) oil, (in) ointment, and (iv) sup-
positories with gly co-gelatin base. The aqueous colloid
(i in 500) contains the element in its most active form,
and is suitable for administration in all cases in which
iodine or an iodide is indicated. Its action is more
gradual, but more certain, than that of iodides, and
there is complete avoidance of " iodism " and nausea.

The whole of the colloidal iodine is absorbed,
whereas 85 per cent or more of the ordinary iodides
administered are excreted within twenty-four hours.

When injected intravenously, the action of colloidal
iodine is more rapid, and as much as 300 c.cs. has been
injected with impunity in cases of pyaemia, and also
to produce softening of fibrous tissue, thus showing

ioo USE OF COLLOIDS IN HEALTH & DISEASE

its absolute non-toxicity. In itself, colloidal iodine is
only slightly parasitotropic and bacteriotropic, but
micro-organisms are very greatly influenced by its
action, and it greatly increases the effect of a subse-
quently administered remedy.

Colloidal iodine is also indicated in syphilis by prior
injection, and also by internal administration, and in
cancer by intravenous injection.

In rheumatism, a piece of flannel soaked in colloidal
iodine attached to the positive pole of a battery and
applied as near as possible to the affected area has been
successful. It has also been used beneficially as a
spray in bronchial and nasal catarrh and internally in
recovery from alcoholism.

Colloidal iodine oil (3 per cent) is very useful for
eczema and other forms of affections and abnormal
conditions of the skin. On application, the iodine
particles penetrate the pores of the skin without stain-
ing the epidermis, the latter being kept supple and
soft by the hydrocarbon oil in which the colloidal
iodine is exhibited and stabilised. Thus, the staining
and hardening effects of alcoholic solutions of iodine,
such as tincture of iodine, are avoided.

In some cases of bad chilblains1 colloidal iodine
oil rubbed in four or five times a day caused every
trace of the condition to disappear in four days.
Equally valuable is this colloid in severe cases of
trench feet with ulceration, and in many cases of
Charcot's bedsores which are so troublesome a com-
plication of spinal injuries in military hospitals. In
the earlier inflammatory stages of lupus erythematosus,

1 Brit. Med. /., May 12, 1917.

I

•8

II
525

t

s

o ^

COLLOIDAL REMEDIES AND THEIR USES 101

before atrophy has supervened, it is far more suitable
than the ordinary form of the drug because of the
absence of irritation. Similarly, it is preferred for
internal administration in the later stages of syphilis,
because there need be no fear of iodism. Parasitic
affections show a striking amenability to this remedy.
In a case of dhobie's itch, in which the disease had
spread from the groin and invaded the trunk, legs, and
arms, under the quite painless application of colloidal
iodine oil the extensive lesions all cleared up in three
weeks ; with ordinary remedies, the case would un-
doubtedly have been more protracted, and the treat-
ment would inevitably have put the patient to a good
deal of pain.

Colloidal sulphur (i per cent) has proved invaluable
in cases where there is a deficiency of this element in
the system. The value of sulphur has long been known,
but the forms in which it is usually administered are
crude. It has been necessary to employ excessively
large doses of an insoluble form of sulphur or to
administer " Harrogate water," or some equivalent
and unpleasant preparation of hydrogen sulphide.
There is little doubt that an insufficient amount of
available sulphur in the system impairs the action of
the liver, with consequent production of intestinal
poisoning (constipation, headaches, arthritis, etc).
Externally, in the form of ordinary sulphur ointment,
the element is in far too coarse a state to penetrate
the epidermis efficiently, whereas in the colloidal form
it does so readily. Colloidal sulphur ointment (5 per
cent) is a brown paste ; when this is rubbed on the
skin its colour rapidly disappears owing to the penetra-

102 USE OF COLLOIDS IN HEALTH & DISEASE

tion of the sulphur into the skin, the colourless disperse
medium remaining behind. This marked distinction
between the behaviour of colloidal and ordinary
sulphur is obvious to every one who has compared
them.

Colloidal sulphur is extremely active, readily com-
bines with protein, and is entirely absorbed in the
stomach. The products of this combination are
rapidly taken into circulation, and those parts of the
organism for which sulphur is necessary are thus
supplied. Ordinary sulphur is not absorbed in the
stomach at all, and passes practically unchanged into
the intestines.

A very interesting property of colloidal sulphur sol
is its power — when taken internally — of completely
deodorising the faeces, and thus acting in precisely the
reverse manner to ordinary sulphur. The importance
of this in phthisis, malignant disease, etc., is obvious.
In many cases of rheumatism and neuritis, and even
in " arthritis deformans," relief has been rapidly ob-
tained by its internal administration. In acute rheu-
matism, the intravenous injection of colloidal sulphur
has proved beneficial.

Colloidal sulphur baths have been of service in
rheumatic conditions and skin affections. The colloidal
sulphur content in the bath is far greater than that of
natural sulphur water, and as the bath contains no
impurities or free sulphuretted hydrogen, it is free from
the many objections associated with the use of natural
sulphur waters.
Sir Malcolm Morris1 has found that among the

Ibid.

COLLOIDAL REMEDIES AND THEIR USES 103

affections in which colloidal sulphur is beneficial are
various forms of acne (including acne rosacea and
seborrhcea), generalised dermatitis, acute psoriasis,
and painful fibrositis, whether of connective tissue, of
muscle, or of joints. Baths medicated with this
colloid are, in his experience, at once soothing and
quickly curative.

Colloidal sulphur increases tolerance to mercury in
syphilis and enhances its efficacy. It has also been
recommended for use by subcutaneous injection in
cancer.

Sulphur can be administered as a simple sulphur sol
or as a complex colloid, di-ortho-amino-thio-benzene
(intramine) as prepared by J. E. R. McDonagh. These
differ somewhat in their action, but for the cases
previously mentioned either form may be used.

Colloidal arsenic (0-2 per cent) in doses of 2 cc. has
an extraordinary effect in pernicious ansemia and
herpes deformans.

In influenza, Capitan 1 obtained cures in 50 per cent
of otherwise hopeless cases with doses 6-9 cc. of colloidal
arsenic and the same volume of colloidal silver. The
colloidal arsenic contains about 4 mgm. per cc. of
arsenic, and the colloidal silver 2 mgm. per cc. of silver,
the solutions being given intramuscularly or intra-
venously. The number of injections varied according to
the effects produced, from 3 or 4 to 6 or 7 in prolonged
cases. In very severe cases, 6 cc. of colloidal arsenic
and 3 cc. of silver were injected intravenously at once,
and twelve hours later the same dose was given
intramuscularly. The dose was repeated next day if

1 Bull. Acad. de mid., Par., 1918, 3* Ser., 80, 388-93.

104 USE OF COLLOIDS IN HEALTH & DISEASE

the patient's state remained grave. If there was
obvious improvement, a single intramuscular injection
of 9 cc. of arsenic and 6 cc. of silver was given. Patients
who recovered after one or two injections showed a
complete change in their general condition ; the
prostration, coma, and delirium disappeared, the
temperature fell rapidly to normal, and the pneumonia
resolved without delay. Apart from a little headache
and nausea, no bad effects were produced. Intramus-
cular injection of stannic oxide in colloidal suspension is
advocated by Netter,1 who has used them in 139 cases,
92 of whom were children and 47 adults. The injections
were given for several days in succession and appeared
to shorten the duration of the disease, diminish its
gravity, and reduce the mortality. The mechanism of
the action of stannic oxide is not clear, as the bacteri-
cidal power of tin is much less than that of silver,
although Netter has found colloidal silver much less
effective than stannic oxide in such cases. Witte 2
recommends the rectal injection of a 2 per cent solution
of collargol3 from two to four times daily as long as the
fever lasts, the patient being given 10 cc. in each
injection. The treatment should be begun as early as
possible, especially in the age-period in which the
mortality is highest, namely, from twenty to forty.

The simultaneous presence of a lipoid or colloidal
protein appears to be essential to the proper reaction
of arsenic. Thus, salvarsan per se has little action on
Spirochceta pallida, which can move readily for some

1 Netter, A., Bull. Acad. de mtd., Par., 1918, 3e Ser, 80, 427-36.

2 Witte, F., Deutsche med. Wochenschr., Berl. u. Leipz., 1918, 44,
1250-1.

3 Collargol is a silver sol.

COLLOIDAL REMEDIES AND THEIR USES 105

hours in a solution of salvarsan. Yet the introduction
of a little serum or digested protein will cause their
immediate death. Organic arsenic compounds cause
rapid sterilisation of the blood stream and disappear-
ance of spirochaetes, but, owing to rapid elimination,
the arsenic is unable to reach every spirochaete or its
spore, and it is for this reason that the intramuscular
or subcutaneous route is sometimes chosen as giving
slower absorption and consequently slower elimination
and more prolonged action (Harrison). The dis-
advantage of this method is the pain usually caused.
Colloidal arsenic is not so easily eliminated and may
therefore be administered by the longer route.
Its low toxicity, combined with the small dosage
required, reduces the risk of its retention to a
minimum.

Colloidal oxides do not prove to be so satisfactory as
the corresponding metals, though Colloidal alumina
(gel) ( Eng. Pat. 104, 609) has shown excellent as-
tringent effects in various kinds of diarrhoea and is less
toxic than the bismuth compounds usually adminis-
tered in such cases.

Various alkaloids have been prepared in the colloidal
state and have been used in medicine. The colloidal
state is the ideal condition for the administration of
alkaloids ; in it they are isotonic with the colloidal
protein of the body fluids, and until this condition has
been reached the full physiological action of the drug
is not complete. The two most important of these
alkaloids are quinine and cocaine. In the usual
quinine solutions, time is wasted converting the alkaloid
to this state and there is frequently considerable upset

io6 USE OF COLLOIDS IN HEALTH & DISEASE

of the conditions regulating the blood and tissue cells.
Thus, when an acid quinine solution is injected intra-
venously, precipitation at first occurs, and the quinine
is rapidly taken up again by the serum as a colloidal
sol, but, in this process, the normal condition of the
serum is destroyed. When colloidal quinine, which is
faintly alkaline, is injected, no precipitation can occur,
and consequently there is no upset of the normal
condition of the blood.

Colloidal quinine sol appears to be free from the chief
drawbacks of quinine salts. As the latter, as well as
the colloid, are readily decomposed in corpore, much
more research is required before much can be said as to
the real action of quinine. Curiously, colloidal quinine
has no action on the parasite of malaria.1

Colloidal cocaine is peculiarly difficult to prepare
and little is therefore known of its value as a local
anaesthetic.

Colloidal combinations. The colloidal elements have
usually been employed singly. This is important
as the improper combination of colloidal sols may
result either in an inert substance or in the production
of conditions precisely the opposite of what is intended.
For instance, A. C. King-Turner 2 has found that
whilst the administration of colloidal palladium is
helpful in epilepsy, yet subsequent administration of
colloidal manganese induced further fits. On the other
hand, suitable mixtures of colloidal elements have
great possibilities, which are, as yet, only dimly realised.
For instance, a mixture of colloidal manganese and
iron can be prepared in an entirely stable form, and

1 Stroud, Lancet, 1917, II, 911. * See pp. 97, 98.

COLLOIDAL REMEDIES AND THEIR USES 107

whilst the therapeutic properties of such a mixture
have not been thoroughly ascertained, it appears that
it not only possesses the remarkable properties of
colloidal manganese and iron, when administered
separately, but also has an additional effect, the nature
of which requires further investigation.

Complex colloids, such as gelatin, gum-acacia or the
protein colloids, are injected intravenously in cases
where it is desired to prevent undue loss of the saline
constituents of the serum. Such colloids adsorb these
crystalloids, retaining them in the blood-vessels,
raising the osmotic pressure, expelling the toxins and
generally reducing the effects of shock. After severe
haemorrhage, both the colloidal and the crystalloidal
constituents are deficient, and an injection of a complex
colloid mixed with a hypertonic saline solution is the
most efficacious restorative. If the saline is adminis-
tered alone, much of it is rapidly excreted and lost.
The simultaneous introduction of a suitable colloid
ensures the adsorption of the saline matter and ensures
its efficacy. Under normal conditions, there appears
to be a considerable proportion of a crystal-colloidal
complex in the body-fluids and for the retention of
health a sensitive or labile equilibrium between the
crystalloid and colloidal contents must, therefore, be
maintained.

CHAPTER X

CONCLUSION

THE form in which colloidal sols are employed has,
naturally, a considerable influence on their effect.
Several German preparations, placed on the market by
British merchants, have given disappointing results
because those physicians who employed them were
insufficiently well acquainted with the nature of
colloidal sols. Thus, for the purposes of ordinary
chemical experiments, sols which have been evaporated
to dryness and redissolved in water immediately before
use are often convenient, but for the much more severe
conditions of medical use such dried sols have proved
unsatisfactory.

Again, it is comparatively easy to prepare sols
which will meet the ordinary requirements of the
chemical lecturer, but such crude preparations are
usually too unstable for medical purposes, or their
stabilising agent or other constituents bring about un-
desirable complications in the patient. It is, therefore,
of the greatest importance that the colloids used by
physicians should be prepared with special skill and
care. Many samples which have been examined show
great variations according to the sources from which
they have been obtained, but it is satisfactory to be
able to state that the preparations to which special

108

CONCLUSION 109

reference has been made in this volume have invariably
proved satisfactory when tested.

There is, in some quarters, an idea that colloidal sols
are too unstable to be of real value in pharmacy
This is undoubtedly true of the crude preparations
made by those who have not the necessary knowledge
and skill, but it is emphatically false when applied
to the preparations to which reference has already
been made.

There is also a disposition on the part of a small
number of recent writers to confuse ideas of the differ-
ence between colloidal elements and complex organic
compounds which may be used either in a colloidal
state or in the form of a true solution. This is an
unfortunate attitude, as there is no necessary in-
compatibility between the two classes of remedies.
The excellent work of Ehrlich and his associates has
had most remarkable results. It has clearly shown a
line of attack which is likely to prove of still further
value in the conquest of syphilis and allied diseases.
On the other hand, it cannot be denied that the use of
arsenic in a highly poisonous form in association with
an organic complex which is intended to neutralise its
toxic action is fraught with risks which, at present,
appear to be much greater than the use of colloidal
elements of very low toxicity.

One unfortunate result of the use of improperly made
colloidal sols has been the publication of a few state-
ments in which the use of colloidal sols as remedies is
condemned in general terms. If the origin of these
statements is traced, it will be found that they have
been made by those who have insufficient knowledge

no USE OF COLLOIDS IN HEALTH & DISEASE

of colloids and have not made the necessary tests
before jumping to conclusions, or they relate to colloidal
sols of low activity, or to those which are not isotonic
with serum and other body-fluids.

Obviously, any conclusions based on such imperfect
data should be regarded with grave suspicion ; they
are certainly inapplicable to the colloids, mentioned in
the foregoing pages, which have been used with such
highly satisfactory results.

No one with sufficient knowledge of colloidal sub-
stances would claim that all drugs should be adminis-
tered solely in this form. There are, in fact, many
crystalline compounds which are invaluable for special
purposes. Thus, there is, in health, a definite equi-
librium between the saline (or crystalloid) and the
colloidal content of the body-fluids which must be
restored when it has been disturbed as the result of
wounds or some bacterial or other disease-producing
agency. Under normal conditions, the cells and serum
are colloidal sols which retain 07 to 0^9 per cent of
crystalloid or saline matter.1 When the saline content
is reduced below the lower of the limits just mentioned,
the administration of a hypertonic crystalloid solution
is usually indicated. If, on the contrary, an excessive
amount of colloidal sol is present, the appropriate
remedy may consist either (i) in raising the concentra-
tion of the crystalloids by the administration of a
saline, or (ii) in precipitating the foreign colloid by
means of another colloidal sol of the opposite electric
sign. The use of salines is well known, but the dis-
covery of artificially prepared colloids which are stable

1 B. Moore, Nature, 1919, 131.

CONCLUSION in

when in the human organism is, however, so recent and
the results obtained from their administration are so
remarkable that it seems desirable in the interests of all
that their general characteristics should be set out
briefly and clearly in order that still further progress
may be made in the utilisation of colloids both in
health and disease.

INDEX

Abscesses, 93, 95
Acid, amino, 60, 89

— carbolic, 67, 68

— gallic, 25

— lysalbic, 7

— nucleinic, 28

— protalbic, 7

— tannic, 25

Acne of the face and hands, 83,

103
" Activated sludge " process, 31,

32

Activity of sols, 57
Adsorption, selective, 2, 3, 107
Agar, 12, 13, 70, 71
Agglutination, 15
Agglutinins, 39, 40, 41
Air, action of, at seaside, 3 1
Albumen, 7, 12, 23, 25, 26, 43,

46, 81

Alcoholism, 100
Algae, unicellular, 13
Alimentary tract, 28, 42
Alkaloids, colloidal, 105
Alumina, colloidal, 105
Aluminium, colloidal, 73

— hydroxide, colloidal, 1 2
Alveolaris, pyrorrhoea, 86
Amino-acids, 60, 89
Amoebae, 13

Anaemia, 78, 88, 103
Angina, Vincent's, 83
Aniline blue, colloidal, 12
Animal fluids, 21

— organisms, 1 3

— structure, 2
Ani, pruritis, 85
Antimony, colloidal, 73, 89-90

— sulphide, colloidal, 1 2
Anti-toxins, nature of, 39, 40
Appendicitis, suppurative, 83
Aqueous phase, 46
Argyrol, 94

Arrhenius, S., 41
Arsenic, 49, 109

— colloidal, 99, 103-105

Arsenic, sulphide, colloidal, 12

Arsenious acid, colloidal, 73

Arseno-benzene, 87

Arthritis, 101, 102

Assaying sols, 56-66

Asses' milk, 22

Assimilation, 2

Atropine, 84

Atrophy, 38, 101

Auld, A. G., 97

Axillae, bromidrosis of, 83, 85

Bacillus coli communis, 70, 71,
88

— tuberculosis, 7 1

— typhosus, 88
Bacteria, i, 17, 36

— action of agglutinins on, 39,
40

— colloidal nature of, 15, 17, 68

— destruction of, 38, 68

— penetration -of cell walls by,
24

— propagation of, 38

— " protection " of, 41

— sensitiveness of, 39
Bancroft, 35

Baths, medicated, 103

— sulphur, 102

Bed sores, Charcot's, 100

Bilharzia, 89

Bismarck, brown, colloidal, 1 2

Bismuth, colloidal, 12, 73

Black background, 58

Bladder, disease of, 28

Blenorrhrea, gonorrhosal, 94

Blepharitis, 84

Blood, carbon dioxide in, 26

— corpuscles, 26, 27

— nature of, 27

— oxygen in, 26

— serum, 40, 5 !
Body fluids, 44, 109

colloidal state of, 37, 49

— viscosity of, 2 5
Boils, 83, 90, 91, 96

"3

INDEX

Bordet, J., 41

Boric lotion, 94

Bromidrosis of the feet, 83, 85

Brownian movement, 5, 57

Burns, 84

Burton, 9, 10

Buxton, 25

Cadmium, colloidal, 73

— sulphide, colloidal, 12
Cancer, 95, 96, 100
Cantlie, Sir James, 83
Capitan, 103
Caramel, 13

Carbolic acid, 67, 68
Carbon dioxide in blood, 26
Carbuncle, 91
Casein, 7, 64, 8 1

— digestion of, 23

— in milk, 22

Catalytic action of colloids, 79
Catarrh, 83, 86, 88, 100
Cells, action of salts on, 24, 25,
28

— embryonic, 95

— growth of, 25

— nature of, 25

— reactions in, 24

— selective permeability of, 24,
25

— structure of, 2, 23

— synthetic, 23
Cellulitis, 88
Cellulose, 81
Cerebro-spinal fluid, 6 1

— meningitis, 86

Cerium hydroxide, colloidal, 12
Chadwick, Sir Edwin, 33, 34, 37
Chambers, 23
Charcot's bed-sores, 100
Charge, electric, on a sol, 9
Cheese, digestion of, 23
Chemical action and electrical

phenomena, 8
Chilblains, 100
Chloroform, colloidal, 13
Chromium hydroxide, colloidal,

12

Cinchona bark, 80
Cleanliness, importance of, 33
Cobalt, colloidal, 73
Cocaine, colloidal, 76, 105, 106-

107

Coccogenic skin disease, 89, 90
Cod liver oil, emulsions of, 46

Collins, Sir Wm., 38
Colloidal metals, electric charge
of, 70

germicidal power of, 68, 73

nature of, 69

— sols, precipitation of, 13-15
protection of, 1 5

— particles, action of electric
current on, 1 1

activity of, 1 8

calculation of electric

charge, 9
double

double electric layer of, 10

electric charge on, 7, 12, 13

oscillation of, 5, 18

rate of movement, 1 3

size of, 5, 20

volume and surface area,

17

— remedies, 76-107

— sols, action of radiations on,
19

precipitation of, 13-15

protection of, 1 5

— state, denned, 4
Colloidogens, 7

Colloids, absorption spectra, 20

— accidental use of, 45

— action of air on, 65

alkalies on, 78

dust on, 65

heat on, 65

light on, 65

membranes on, 43

— adsorption of, 68

— advantages for internal use,
75

Colloid and crystalloid, equi-
librium between, 107

Colloids and digestion, 2, 42-
44

— and solutions, distinction
between, 16

— appearance of, 57

— characteristics of, 7

— coagulation of, 50

— colour of, 19

— colour, variations of, 20

— complex, 107

— determination of activity,
57-66

— dosing of, 53, 79

— effect of serum on, 65-66
time on, 65

— equilibrium of, 5 5

INDEX

Colloids, German, 50

— hydrolysis of, 43

— injection of, 34, 54, 80, 85,
88, 91, 93, 96, 97, 99, 103,
104, 1 06

— intensity of reaction, 78

— mixed, 106

— nature of, 1-20

— preparation of, 51, 54

— properties of, 1-20

— protection of, 5 1

— protein, 107

— settling time of, 65

— stabilising, 5 5

— stability of, 50, 51, 55, 66

— under ultra-microscope, 57

— unstable, 51, 54, 60, 108
Colour of colloids, 19
Common salt as colloid, 6
Compounds, dissociation of, 9
Condensation, 53, 54
Congenital epilepsy, 98
Conjunctiva, 82

— oedematus, bulbar, 94
Conjunctivitis, gonorrhoeal, 83

— phlyctenular, 83
Constipation, 101

Copper, colloidal, 12, 73, 81, 95-
97

— hydroxide, colloidal, 12
Cow's milk, 21, 22
Corneal ulceration, 94
Corrosive sublimate, 72
Cretinism, 78

Crookes, Henry, 52, 68, 69, 70,

73. 74

Crystalloids under ultra-micro-
scope, 58

— and colloids, equilibrium be-
tween, 107

Cuvette, 59
Cystitis, 83, 86

Dacryocystis, 84

Deltas, formation of, 33

Dermatitis, 85, 103

Dextrin, 64

Dhobie's itch, 101

Dialysis, n

Diarrhoea, 105

Diatoms, colloidal, 13

Diffusion, n, 28

Digestion and colloids, 2, 42-44

— nature of, 26, 43

Digestion and colloid products,
action of colloidal iron on, 89

Dilute solutions, germicidal
power of, 69

Diphtheria toxin, 40

Diplococcus, 71

Dipsomania, 80

Disease, origin of, 36, 37

Disease-producing organisms,
evolution of, 38

Disinfectants, colloidal, 67

Disperse phase, 4, 46

Dispersion medium, 4, 51

— power of soaps, 34
Dissociation of salts, 9
Donnan, 43

Double electric layer, 10
Drainage, importance of, 33
Drugs, action of, 79

— dose and effect, 47

— erroneous results from intro-

duction of, 17

— ionisation of, 79
Dyes, 7
Dysentery, 83

Ear affections, 83
Ebonite, electrification of, 8
Eczema, 83, 85, 89, 90, 100
Ehrlich, 49, 109

Electricity, influence on animal
organisms, 13

— use of, as a remedy, 1 3
Electrification of colloidal par-
ticles, 7

Electrolytes, 6, 7, 10
Electronegative colloids, 7
Electropositive colloids, 7
Embrocations, 46
Emetics, 47
Emulsifying agents, 46
Emulsion, 39, 46
Emulsoids, 6, 23, 25
Endoscope, 86
Enzymes, 17, 42, 78
Eosin, colloidal, 12

— solution, 62
Epiditymitis, 83
Epilepsy, 97, 98, 106
Erysipelas, 88
Erythematous lupus, 100
Eustachian tubes, 86
Faeces, deodorising, 102
Faraday, 80

n6

INDEX

Ferments, 42

Ferric hydroxide sols, 12, 27

Fever, paratyphoid, 97

Fibrositis, 103

Fibrous tissue, 99

Field and Teague, 40

Fish-agar, 74

Fluid, cerebro-spinal, 61

— gland, 78

— thyroid, 78
Follicular tonsilitis, 83
Folliculitis, acute, 90
Foot-and-mouth disease,
Formalin, 68

Formic aldehyde, 54
Fuchsine, colloidal, 54
Furunculosis, 90

Gallic acid, 25

Galvanotropism, 25

Garnet, 81

Gelatin, 4, 6, 13, 21, 22, 23, 24,

28, 39, 64, 107
Gels, denned, 14

— formation of, 14

— haemolysis of, 27
Germicides, colloidal, 67
Gland, prostate, 86
Glands, 78

Glass, electrification of, 8

Gleet, 86

Globulin, colloidal, 12

Glue, 64

Gluteus medius, 96

Glyco-gelatin, 97

Glycogen, 48

Glycophosphates, 48

Gold chloride, 54

— colloidal, 9, 19, 54, 73, 80-8 1

— metallic, 3

— number of sols, 63-65
Gonococcal urethritis, 90
Gonococcus, 71
Gonorrhoea, 83
Gonorrhoea! blenorrhoea, 94

— conjunctivitis, 83

— ophthalmia, 83, 93

— prostatic gleet, 86
Graham, Thomas, 3, 16
Granulama pupendi, 90
Graphite, colloidal, 73
Gum acacia, 21, 24, 107

— arabic, 2 1 , 64

Gutbier and Resenschack, 20

Habgood, W., 90

Haematin, 16

Haemoglobin, 12, 26, 27, 43, 88,

89

Haemolysis, 27
Haemorrhage, 107
Haemorrhoids, 85
Harrison, 105
" Harrogate water," 101
Headaches, 101
Henri, 26

Herpes deformans, 103
Hewin and Mayen, 19
Hewlett, R. Tanner, 71
Histone, 25

Hoffmann, violet, colloidal, 12
Homoepathists, 53
Hovell, J. Mark, 86
Human milk, 21, 22

— system, action of radiations
on, 19

Hydrogen sulphide, 78
Hydrolysis, 53, 54, 76
Hygienic uses of colloids, 29
Hypertonic salt solution, 107,
109

Impetigo, 83, 90, 92

Indigestion, 44

Indigo, colloidal, 12

Influenza, 86, 103

Injection of colloids, 34, 54, 80,

85, 87, 88, 91, 93, 96, 97, 99.

103, 104, 106
Interstitial keratitis, 84
Intestinal troubles, 83
Intramine, 90, 103
Iodine, colloidal, 13, 18, 56, 65,

76, 77, 87, 96, 99-101

— in alcohol, 18

— in animal organisms, 78

— oil, colloidal, 99-101

— stainless, 77

— tinctures, 77

" lodism," 99, 101

lonisation of drugs, 76, 79

Ionised state, 79

Ions, 79

Iridium, colloidal, 73

Iron as protein compound, 88

— carbonate, objections to use
of, 89

— colloidal, 12, 77, 88, 89, 106

— compounds, 89

— hydroxide, colloidal, 1 2

INDEX

117

Iron in animal organisms, 78

— in human organism, 88

— solutions as remedies, 77
Isinglass, 64

Itch, Dhobie's, 101

Jones, B. Seymour, 86

Kala-Azar, 90
Keratitis, interstitial, 84
King-Turner, A. C., 97, 106
Kirk, E. W., 90

Lact-albumen, in milk, 21, 22
Lead, colloidal, 12, 73
Lecithin, 13, 48
Leishmonnoris, 89
Lesions, 85, 93, 101
Leucorrhoea, 86
Levinson, W. E., 90
Linder and Picton, 1 2
Liniments, 46
Lipoids, 87, 104
Lister, 36
Living organisms, 2

— and dead organisms, differ-
ence in action, 1 6, 17

Livingstone, Dr. McFarland, 93,

94

Lottermoser, 15
Lupus erythematosus, 100
Luton, 97
Lysalbic acid, 7

McDonagh, J. E. R., 87, 91, 103
MacLeod, C. E. A., 83
MacMunn, J., 86
Magdalene blue, colloidal, 1 2
Magnesium, colloidal, 73
Malaria, 88, 106
Malignant disease, 102
Manganese, colloidal, 90-95, 96,

98, 106

Mastic, colloidal, 1 3
Mayen, 19

Mayer, Schaffer and Terroine, 20
Medical possibilities of colloids,

50-52, 1 8
Medicine, use of colloids in, 18,

45, 52
Membranes, permeability of, 2,

3, ii, 17, 24, 43
Meningitis, cerebro-spinal, 86,

99

Merchal de Gers, 96
Mercury chloride, 78
colloidal, 73

— colloidal, 12, 70, 71, 73, 76,
80, 86-88, 89

— compounds, 47, 77

— cyanide, colloidal, 73

— ointment, 84
Metabolism, 96

Metals, colloidal, activity of, 79

catalytic action of, 79

effect of, on blood, 79

germicidal power of, 69

use of, 77

Methylene violet, colloidal, 12
Micrococcus catarrhalis, 88
Micro-organisms and disease,

36-41

Migration of particles to elec-
trodes, n, 15
Milk, asses', 22

— coagulation of, 47

— cows', 21, 22

— human, 21, 22

— lime water in, 22

— protective colloids in, 21, 22
Miller, 25

Molybdene blue, colloidal, 12
Moore, no

— and Roaf, 2

Morris, Sir Malcolm, 85, 91, 93,

102

Mud, precipitation of, 33
Mustard gas, 91

Nanes, 25

Nasal catarrh, 83, 86, 100

Nausea, 99

Necrosis, 82

Nervous diseases, phosphorus in,

48

Netter, 104
Neuritis, 102
Nickel, colloidal, 99
Nucleinic acid, 28
Nutrient broth, 70, 72

— gelatin, 73

Obesity, 97

(Edema of the face, 91

QEdematus bulbar conjunctiva.

94

Oil emulsions, 1 3
Ophthalmia, gonorrhceal, 83, 93

— purulent, 84

INDEX

Organisms, animal, 13

— living and dead, 43

— structure of, 2

— vegetable, 1 3
Ostwald, Wolfgang, 6, 20, 26
Otitis media, 83

Oxides, colloidal, 105
Oxygen in blood, 26
Ozone, 31

Paal, 95

Palladium, colloidal, 73, 76, 96,

97-99, 1 06

Parasitic affections, 101
Paratyphoid fever, 97
Parchment as a membrane, 3, 16
Pellicle, 26
Pepsin, 47
Peptisation, 54
Peptones, 7, 16
Perineal eczema, 85
Permeability, selective, 2, 3, n,

43

Perrin, 25

Petroleum, emulsions of, 46

Phenol, 67, 68

Phlyctenular conjunctivitis, 83

Phosphorus in the animal or-
ganism, 78
— nervous diseases, 48

Phthisis, 1 02

Picton, 12

Piles. See Haemorrhoids

Platinum black, 79

— colloidal, 12, 73, 79, 97
Pleuritis, 97
Pneumococcus, 88
Pneumonia, 104
Podophyllin, tincture of, 45
Poison and reactions of metallic

sols, 42

Poisoning, 42, 78
Preparation of colloidal sols, 53-

56

Prostatic gleet, gonorrhoeal, 86
Protalbic acid, 7
Protalbumoses, 43
Protected colloids, 1 5
Proteins, 60, 87, 102, 104, 105

— colloidal, 107
Protoplasm, 2, 23, 24, 25
Pruritis ani, 85
Prussic acid, 78
Psoriasis, 103
Puerperal septicaemia, 85

Pupendi, granulama, 90
Purgatives, 47
Purulent ophthalmia, 84
Pus, 94

— cells, 71
Pustular, eczema, 83
Pyaemia, 99

Pyorrhoea alveolaris ,86
Pyrexia, 97
Pyrogenic cocci, 88

Quincke and Helmholtz, 10
Quinine, colloidal, 76, 105, 106

— disulphate, 62

— hydrochloride, 80
Quinsies, 86

Rachlmann, 25

Radiations, action of, on sols, 19
Rahe, 25
Rayleigh, 19
Rennet, 22, 47
Resenschack, 20
Resin, colloidal, 13
Rheumatism, 78, 100, 102
Rhinitis, 86
Rhodium, colloidal, 73
Rigg's disease, 86
Ringworm of the body, 83
Roaf, 2

Roe, A. Legge, 83
Rosaniline hydrochloride, col-
loidal, 12

Saline matter in the organism,
107, 109

— solutions, use of, 107, 109
Salt, action on colloids, 43

— decomposition of, 9

— water, electrolytes in, 3 3
Salvarsan, 104, 105

S chaffer, 20

Schlcesing, 33

Scirrhus, 95

Scopolamine, 84

Seborrhoeic eczema, 90

Selective permeability, 2, 3, u,

17, 24, 43

Selenium, colloidal, 13, 73
Semi-colloids, 7
Septicaemia, 83, 85, 86
Septic tonsilitis, 83
Serum, 43, 51, 54, 107

— action on colloids, 65, 66

— immune, 39

INDEX

119

Serum, syphilitic, 60
Settling, time of, 65
Sewage, 29-32

— bacterial treatment of, 32

— nature of, 30

— precipitation of colloids in, 3 1

— purification of, 30

— sludge, coagulation of, 32

nature of, 32

Shellac, colloidal, 13
Sherrer, T., 81

Shingles, 86

Shock, 107

Silicic acid, colloidal, 12, 13, 64,

81

Silk, electrification of, 7
Silver bromide, colloidal, 12

— chloride, colloidal, 12

— colloidal, 9, 12, 56, 70, 71, 72,
73. 75, 76, 77, 81-86, 103

— iodide, colloidal, 1 2

— metal, germicidal power of,

74

— nitrate, 84

— stainless, 77
Simpson, W. J., 71

Sizes of colloidal particles, 5

Skey, 33

Skin disease, coccogenic, 89, 90

— permeability of, 1 9
Soap, 5, 7, 29, 33-35

— action of, 34

— hydrolysis of, 3 5

— nature of, 35
" Soil," 38

Sol, defined, 4, 16

Solids with liquid properties, 6

Soluble prussian blue, colloidal,

12

Sores, soft, 83
Spencer Herbert, 38
Spirochaeta pallida, 104, 105
Spring catarrh, 83
Sprue, 83

Stability of colloids, 50, 51, 66
" Stability number " of colloids,

64, 65

Stannic acid, colloidal, 8 1
— oxide, colloidal, 104
Staphylococcus pyogenes, 71, 91
Starch, colloidal, 13, 64
Stebbing, 20
Streak cultures, 70, 71
Streptococci, 71, 96
Sulphur baths, 102, 103

Sulphur colloidal, 13, 54, 55,
73, 76, 101-103

— in the animal organism, 78

— ointment, 101
Suppuration, chronic, 83
Suppurative appendicitis, 83
Suspensions and colloids, differ-
ence between, 16

— properties of, 1 5
Suspensoid particles, 6
Svedburg, 20
Syphilis, 60, 87, 100, 103

Tannin, 25

Tantalum, colloidal, 73
Teague, 40
Terroine, 20
Thompson, 19
Thorium, colloidal, 73

— hydroxide, colloidal, 1 2
Thyroid fluid, 78

Tin, colloidal, 73
Tinctures, 45
Tinea versicolor, 83
Tin oxide, colloidal, 12
Titanic oxide, colloidal, 12
Tobacco disease, 36
Tolman and Vliet, 62
Tonsilitis, 83, 86
Toothache 95
Toxaemia, 85

Toxins, action of electric cur-
rent on, 40

— decomposition, 39

— destruction of, 68, 107

— diphtheria, 40

— nature of, 15, 39, 40
Trench feet, 100
Trituration, 53
Tuberculosis, 97
Tulloch, W. J.( 41
Turbinates, enlargements of, 86
Tyndall, John, 61
Tyndallmeter, 62

Tyndall phenomena, 61-63

Ulcers, various, 83, 84
Ulcus molle serpiginosum, 90
Ultra-microscope, 57
Unsanitary conditions, effect of,

44

Urea, 28

Urethritis, gonococcal, 90
Uric acid, protection of, 2
Urine, 27, 28

120 INDEX

Urticaria, 85
Uterine fibroids, 97

Vaccine injections, 91, 92
Valsava's inflation, 86
Valuation of colloids, 57
Vanadic oxide, colloidal, 1 2
Vegetable fluids, 21
— organisms, 1 3
Vincent's angina, 83

Water, purification of, 29, 32-33
Weimarn, Von, 6

Wells, T. H. Anderson, 85
Whooping-cough, 86
Witte, 104

Yellow fever, 36

Zinc, colloidal, 73

Zirconium hydroxide, colloidal,

12

Zsigmondy, 20, 55, 58, 64
Zymotic diseases, 36, 38

PRINTED BY WILLIAM BRENDON AND SON, LTD., PLYMOUTH, ENGLAND

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