107 
Tolomei ( 423 ), Effront ( 156 ), and Buchner ( 103 ) the oxidases of these 
yeasts oxidize guaiacum and are concerned in the production of the 
bouquet of certain wines. To these also are attributable the dark- 
ening in color of zymase (expressed yeast juice) on exposure to the 
air, and also the rise in temperature produced when large amounts 
of yeast cells are exposed to the air. These observations by Tolomei 
and Effront on the occurrence of oxidases in yeasts have been con- 
firmed by Grass ( 202 ), only this author found these oxidases to be with- 
out action on guaiacum or liydroquinone. On the other hand, like 
his spermase, they were found to be capable of oxidizing tetra-methyl- 
para-phenylene diamin, and other amino compounds, such as phenyl- 
hydrazin. Hence according to Gruss the yeast oxidase belongs to 
the class of amino-oxidases. 
Issajew ( 221 ) has also investigated the oxidases of yeast and has 
confirmed the work of the earlier observers mentioned. He found 
that the oxidase in yeast oxidizes both the easily oxidizable sub- 
stances which the yeast contains and also other easily oxidizable 
substances, such as the polyphenols, and that the upper yeast 
0 Oberhefe ) contains, as one might naturally expect, more oxidase 
than the under yeast ( TJnterhefe). 
Various bacteria, such as the bacillus of malignant pustules (Diet- 
rich and Liebermeister ( 139 ), and the colon bacillus (Roux ( 353 )), have 
been found to contain oxidases. The oxidase of the latter was found 
to oxidize hydroquinone, gelatin, peptone, etc., with the production of 
a brown pigment, and to be active only in the presence of oxygen. 
