40 
twenty-four hours became very strong. The same moist tobacco 
was heated in a closed vessel to 95° C. for ten minutes and then 
moistened with the same solution, but no trace of the quinone odor 
could be perceived, even after twenty-four hours. The same negative 
behavior was observed with tobacco cured with artificial heat at a 
higher temperature and therefore containing no catalase (flue-cured 
bright-yellow Virginia tobacco), no trace of the odor being produced. 
The sweated tobacco which was used in the tests with hydroquinone 
was free from oxidase and peroxidase and did not contain any other 
known enzym;' it therefore follows that a- and f-catalase belong to 
the class of oxidizing enzyms. 
The smell of quinone produced by the action of animal catalase 
upon hydroquinone is less marked, perhaps on account of the presence 
of too large a proportion of impurities of a protein nature. But this 
oxidation can be observed well when to a concentrated extract of beef, 
made at the ordinary temperature, 1 per cent of hydroquinone is added 
and the mixture is left for several days in a large flask plugged with 
cotton. The hydroquinone produces a precipitate and also a gradual 
and moderate darkening of the mixture. It furthermore prevents, in 
that concentration, bacterial development. When after several days 
a little oxalic acid is added, a very marked odor of quinone is developed, 
becoming much stronger on heating. : 
While certain oxidases can oxidize very dilute eugenol to vanillin. 
catalase seems incapable of accomplishing this; at least no odor of 
vanillin was noticeable after one day. Nor is ethyl alcohol oxidized 
by it either to aldehyde or to acetic acid, and cyanin is not decolorized 
by it, although this compound is easily destroyed by other oxidizing 
agents, as, for example, hydrogen peroxid. Saligenin and indigo car- 
min are not attacked by it, at least not in neutral solution. 
Other tests were made to ascertain whether carbonic acid would be 
produced from various organic compounds by the action of a-catalase. 
Sweated tobacco, rich in a-catalase, was well extracted with chloroform 
water at the ordinary temperature, pressed, and an amount correspond- - 
ing to from 35 to 40 grams of dry matter put in a flask, after being 
moistened with solutions of the organic substances to be tested, and 
heated to from 55° to 60° C. ina current of air, which had passed through 
a solutionof caustic potash and then through a flask containing chloro- 
form. For absorption of the carbonic acid a solution of barium hydrate 
containing 0.62 per cent of BaO was used. Each test lasted one hour. 
Control tests were also made, since not only the.absorption of carbonic 
acid from the air by the tobacco before it was placed in the flask, but 
‘Tt is scarcely necessary to state that the common hydrolyzing enzyms—diastase, 
emulsin, papain, ete.—have not the power of oxidizing hydroquinone to quinone. 
The writer has especially assured himself on this point. 
