29 
that although hydrogen sulphid injures the a-catalase at the ordinary 
temperature, this injury proceeds but slowly. 
Schcenbein reports’ that plant juices instantly lose their catalytic 
power upon coming in contact with hydrogen sulphid, but the above 
test shows that this power is not so easily destroyed, after all. 
A second test yielded essentially the same result. In both cases a 
considerable amount of sulphur was set free, leading to the inference 
that catalase probably promotes the oxidation of H,S by the oxygen 
of the air. 
BEHAVIOR TOWARD HYDROXYLAMINE. 
One gram of hydrochlorid of hydroxylamine’ dissolved in a little 
water was neutralized with sodium carbonate, and the solution diluted 
to 20 ce. After the addition of 1 gram of sweated tobacco the mix- 
ture was allowed to stand for eighteen hours. The filtrate was now 
found to have completely lost every trace of catalytic power. This 
was not the case, however, with the insoluble portion, which, after 
washing and suspending in 20 cc. of water with the addition of 10 
ec. hydrogen peroxid, developed 29 cc. oxygen in fifteen minutes. 
In the same length of time 62 cc. were obtained in the control case. 
BEHAVIOR TOWARD PHENYLHYDRAZINE. 
A concentrated cold-prepared extract of sweated tobacco® was salted 
out with ammonium sulphate, the precipitate pressed between filter 
paper, dissolved in a little water, and some phenylhydrazine acetate 
added. After twenty-four hours a small amount of precipitate was 
formed, which yielded some oxygen gas with hydrogen peroxid, while 
the filtrate gave only traces. It therefore seems that #-catalase forms. 
a still somewhat active compound with phenylhydrazine. This, how- 
ever, requires further study. : 
In testing @-catalase, a weak alkaline solution was mixed with some 
phenylhydrazine acetate. After twenty-four hours a precipitate was 
formed, but the amount was insignificant. The clear filtrate, upon 
the addition of 5 cc. hydrogen peroxid, in ten minutes yielded 11 ce. 
oxygen, while in the control case 52 cc. of oxygen were obtained. 
One would naturally suppose that if ketone or ordinary aldehyde 
groups were present the enzymic activity would be totally destroyed 
in a short time.* 
1 Journ. prakt. Chem., 1863, p. 340. 
?This salt has a strong acid reaction, hence experiments made directly with it 
are not conclusive. The acid reaction has to be removed, since it alone would suffice 
to injure or kill the enzym. 
* Prepared with the addition of 10 per cent alcohol to prevent bacterial development. 
*Emulsin also preserves its powers after it has been in contact with phenylhydra- 
zine acetate for twenty-four hours. It can be precipitated with alcohol and stilt 
exhibit its action on amygdalin. 
