127 
that the oxidation of the phenols is accompanied by the evolution of 
carbon dioxide. With certain colloids the artificial oxidase result- 
ing from admixture with the manganese salt could be precipitated 
with alcohol and the precipitate redissolved with water without los- 
ing its oxidizing powers. For the most part heat destroys the oxi- 
dizing power of such solutions. Thus when heated to 105° C. for 
twenty minutes the solution no longer oxidizes guaiacum nor certain 
diphenyl methane derivatives. The effect of heat is also seen in the 
several amounts of oxygen absorbed by pyrogallic acid under the 
influence of the fresh and heated solutions; thus: 
Absorption in cubic 
centimeters. 
1. With the fresh unboiled solution the following 
amounts of oxygen w r ere absorbed 
45. 0 
38.0 
47.0 
2. With the boiled solution 
0.0 
5.0 
3.0 
It is evident, therefore, that colloidal solutions of manganese hydrox- 
ide obtained by the action of caustic soda on manganese salts in the 
presence of albumin and similar colloidal substances exhibit properties 
closely resembling those of the natural oxidases. 
Garrigou ( 180 ) has found certain metals to exist in a colloidal con- 
dition in mineral waters. According to this author, therefore, such 
substances possess the properties of natural oxidases, and to them 
he ascribes the beneficial results which attend the drinking of such 
waters and which are the result of more vigorous oxidations in the 
tissues. A. and L. Lumiere and Chevrotier ( 280 ) have confirmed the 
work of Trillat ( 436 ) on the oxidizing power of colloidal solutions of 
manganese and the general analogy of such solutions to the oxidases. 
According to these authors, colloidal solutions of any metal capable 
of existing in two or more states of oxidation should exhibit proper- 
ties similar to those shown by the oxidases, the state of division of the 
colloidal substance also determining the oxidizing power of the sub- 
stance. As a matter of fact, they found that emulsions of iron and 
cerium in albumin, gelatin, or gum, have the power to blue guaiacum, 
oxidize hydroquinon,pyrogallol,guaiacol, and para-phenylene diamin, 
but less actively than emulsions of manganese. These authors also 
sought to utilize these properties in destro 3 nng the bacterial poisons, 
since it is known that such poisons are destroyed by powerful oxi- 
dizing agents. As a matter of fact, they found that the death of an 
animal by tetanus toxin was greatly delayed by the administration 
of these artificial oxidases, and that with a slightly acid oxidase and 
tetanus toxin the animal did not show the slightest sign of intoxi- 
cation. 
