ON COLLOID CHEMISTRY AND ITS INDUSTRIAL APPLICATIONS. 163 
alkaline, and has a prevailing hydroxyl concentration. In many 
diseases this alkalinity is reduced with consequent toxic symptoms. 
To restore normality it is therefore necessary to reduce the concentra- 
tion of the hydrogen ions or to increase that of the hydroxyl ions. 
The choice between these must depend on other circumstances, and 
especially on the relation of the relative concentrations of the serum 
of the patient in disease and in health. 
An interesting instance of the importance of a knowledge of the 
‘properties of colloids in the treatment of disease occurs in anemia. 
In the simplest case this disease is due to a deficiency of iron in the 
hemoglobin in the blood stream. Hemoglobin is electro-positive, 
and to increase its amount without disturbing the general character- 
istics of the sernm, any iron compound administered must also be 
electro-positive when it enters the blood stream. For this reason 
iron carbonate and hydroxide are useful whilst such compounds as 
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 converted into ferric chloride 
or analogous compounds by the gastric juices and so largely fail to 
reach their destination in a useful form. 
Colloidal iron, on the contrary not being affected by these juices, 
is able to enter the blood stream in a satisfactory and therapeutically 
active form. 
The retention of an unnecessary amount of any substance in the 
blood stream or tissues tends to induce toxicity. The extremely 
minute size of the particles in the colloidal sols is such that they pass 
readily through the tissues and the chances of their being improperly 
stored in the system are correspondingly! minimised. In view of 
the foregoing facts it is not surprising that colloids are coming more 
and more to the front in pharmacology", particularly those which 
approach the state of true solutions. A good example is seen in 
Fischer’s work on cedema!® in which he has shown that cdema 
results from the imbibition of water by certain colloids. 
The choice of a colloidal sol suitable for a particular pathological 
condition must naturally depend on the cause of that condition. 
This can only be ascertained by trial, though certain broad conclu- 
sions may be reached with respect to the chemical behaviour of 
different substances. In the collodial state, however, many 
substances react entirely differently from what may be regarded as 
their normal behaviour. Thus, colloidal sulphur sometimes acts 
indirectly as an oxidizing agent and both metals and non-metals act 
in a manner which cannot be predicted on general chemical grounds. 
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. Indeed, colloidal manganese 
13 Sir J. J. Thomson (Royal Institution, March, 23rd, 1912) stated that one drop 
of a metallic collosol contains more than 1,000,000,000,000 particles of metal which 
cannot be detected by ordinary methods and pass readily through the pores of a 
filter. : , 
“4 Porges, Koll. Zeit. 5, 301 (1909). 
15 Das Odem; Eine Expt. u. theor. Untersuchg, d. Physiologie und Patholegie 
(1910). 
