179 
Vines . — The Proteases of Plants (III). 
them with those obtained with papain and with the Pineapple. Reference 
to those results shows, in the first place, that whilst in those cases it was 
possible to arrest peptolysis, in the case of Yeast it was possible to arrest 
fibrin-digestion. This is an important piece of evidence in the inquiry into 
the nature of 1 vegetable trypsin 5 : the arrest of one of the two processes 
would have been a suggestive fact, but the arrest of both of them, in different 
material, is a weighty argument. Again, in papai’n and in the Pineapple, 
peptolysis was found to have a narrower reaction-range than fibrin-digestion ; 
whereas in Yeast the contrary is the case. I will defer any discussion 
on this point to the end of this paper. The experiments with other plants 
that yet remain to be described give results agreeing in the main with those 
of Yeast. 
Agaricus campestris. 
The material used consisted of dried Mushrooms ground to fine 
powder. 
3grms. of the powder were extracted with 120CC. of 2 % NaCl-solution, and the 
mixture was placed on a filter for some hours in the cold. The filtrate was a dark, 
slightly acid liquid, giving no tryptophane-reaction : to it was added i grm. Witte- 
peptone, and toluol to about i %. 40 cc. were put into each of 3 bottles : the 
contents of No. 1 were left at natural reaction; those of No. 2 were made alkaline 
with Na 2 C 0 3 0*5%; those of No. 3 were acidified with HC 1 o-i %: to each bottle 
o-2 grm. fibrin was added. 
After 24 hours’ digestion in the incubator at 39°C. the results were:— 
1. 2. 3. 
fibrin 
gone 
unaltered 
unaltered 
tryptophane 
marked 
strong 
distinct 
after 48 hours’ digestion : — 
fibrin 
unaltered 
unaltered 
tryptophane 
— 
— 
marked 
Conclusion : peptolysis somewhat retarded by acid, promoted by alkali: fibrin- 
digestion arrested by deviation from normal reaction, whether acid or alkaline. 
Here again, as in the case of Yeast, it is fibrin-digestion that is the 
more affected by increased acidity or by alkalinity, the differential action 
being well marked. 
Hordeum sativum . 
In view of Weis’s ( 18 ) important investigation of the proteolysis of 
Malt, I took the opportunity of making some experiments upon it. It 
offers this disadvantage, that the extracts give a tryptophane-reaction 
to begin with, as might be expected. By previous experiment I had 
