in£ that certain indamines like toluene-blue result from the oxida- 
© 
tion of meta-toluene diamin and para-phenylene diamin, and Bind- 
schedler’s green from dimethyl-para-phenylene diamin and dimetliyl- 
anilin, and that the synthesis of various eurhodins may be accom- 
plished in the same manner. An easy method of demonstrating such 
reactions consists in placing a small amount of an animal tissue, 
such as the liver, on a test paper which has been prepared with the 
two chromogenic components of the dye. If, for example, a small 
amount of fresh liver be placed upon a test paper which has been sat- 
urated with a sodium carbonate solution of a-naphthol and para- 
plienylene diamin, the place on the paper occupied by the tissue is 
soon deeply colored, whereas the other portions of the paper show 
only a slight coloration. According to these authors, the change in 
question is represented by the following equations : 
/C 6 h 4 nh 2 
1. C 6 H 4 (XH 2 ) 2 + C 10 H 7 OH + O = NH< +h 2 o, 
\c 10 h 6 oh 
and 
/C 6 H 4 NH 2 /C 6 H 4 XH 2 
2. NH< +0=N< +H 2 0. 
X C 10 H 6 OH | \c 10 h 6 o 
I i 
Thus one atom of oxygen goes to effect the synthesis of the leuco 
compound and a second atom to effect the oxidation of the leuco 
compound to the coloring matter. When the solution of the chro- 
mogens is allowed to stand in contact with atmospheric oxygen, the 
coloring matter is. formed only slowly in the presence of alkalies; 
when the animal tissue is added the process is greatly accelerated. 
It was shown by these authors that these oxidations are most readily 
accomplished by extracts of cells, the body fluids and secretions being 
comparatively inactive. In this respect the change is analogous to 
the destruction of glucose, a change which is readily accomplished by 
extracts of red and white blood cells in physiological salt solution, but 
not by blood serum. They reached the conclusion, therefore, that 
the oxygen exciters responsible for these oxidations are contained 
only in the cells. That such is the case is evident also from the con- 
duct of such extracts and secretions toward guaiacum and hydrogen 
peroxide. Extracts of red blood cells blue a mixture of guaiacum 
and hydrogen peroxide instantaneously, whereas the blood serum 
causes no change of color, or if it acts at all it does so very feebly. 
While they knew nothing of the particular cell components respon- 
sible for these changes, they seemed to think that their observations 
furnished evidence, hitherto wanting, of a single oxidizing ferment. 
By precipitating the macerates of fresh organs with alcohol and 
washing the precipita L ,e thus obtained with alcohol and ether, the / 
obtained dry powders which retained their oxidizing powers for a 
