14 
Vines . — Tryptophane in Proteolysis. 
yeast until it became brittle enough to grind in a mill : 
20 grms. of this fine powder were extracted with 400 cc. 
distilled water for some time, and then thrown on a filter : 
the whole process of extraction and filtration lasted about 
4 hours : the filtered liquid was slightly turbid, distinctly 
acid, and gave no tryptophane-reaction. 
The result of these experiments is to prove the existence 
in Yeast of a proteolytic enzyme which is active in neutral 
and in acid liquids, but not in alkaline. 
The following mixtures were prepared : each bottle (except No. 1) 
contained extract of dried yeast diluted with an equal bulk of distilled 
water, 50 cc. in all ; to each 5 drops of 4 % HCN were added. 
1. contained 50 cc. undiluted yeast-extract. 
2 a. 
added 
1 grin. 
fibrin. 
b. 
}) 
j? 
Witte-peptone. 
3 a - 
;j 
a 
fibrin -f-o- 1 cc. HC 1 ( = 0-2 °/ Q ). 
b. 
)> 
}) 
Witte-peptone „ 
4 a. 
>) 
)> 
fibrin, neutralized. 
b. 
)? 
Witte-peptone, neutralized. 
5 a. 
)> 
a 
fibrin, neutralized, -f- -25 grm, Na 2 C 0 3 . 
b. 
jj 
>> 
Witte-peptone, neutralized, ,, 
placed 
in the incubator at 4 p.m. 
Next morning at 10 a.m. the results were — 
1. weak tryptophane-reaction. 
2 a. distinct „ 4 a. marked reaction. 
b. marked „ b. strong „ 
3 a . faint „ 5 a. none , 
b. marked „ b. faint . 
In a repetition of the experiment with 4 a and 4 b, I satisfied myself 
that the striking reaction is given even when the liquid remains quite 
neutral throughout. 
now slightly 
acid, 
both 
I alkaline. 
t 
Bacteria of Putrefaction. 
The fact that putrefying proteids undergo a decomposition 
somewhat analogous to that effected by trypsin, but more 
far-reaching, has long been known. The formation of 
tryptophane in putrefaction seems to have been first recorded 
by Claude Bernard (14), as also the fact that continued putre- 
faction causes the disappearance of this substance. 
