Vines. — The Proteases of Plants (///). 183 
are indicated : the reaction-range of peptolysis is wider than that of fibrin-digestion, 
though they both are wide. 
Even in this experiment the differentiation is not so marked as might 
be desired : but it suffices to show that here, as in the case of Yeast, 
fibrin-digestion is more readily affected than peptolysis by increased acidity 
or by alkalinity. 
Nepenthes . 
In a previous paper ( 16 , p. 570) I showed that pitcher-liquid not only 
digests fibrin in acid reaction (0-3 °/ o HC1), but also effects peptolysis as 
indicated by the tryptophane-reaction. The following are some recent 
experiments made with a view to differential action. The liquid used was 
obtained from various species, and was neutral. 
To 60 cc. of the liquid 1 grm. of Witte-peptone was added, and HCN to 0-2 % : 
20 cc. were put into each of 3 bottles, with 0-2 grm. fibrin, treated as follows: — No. 1, 
Na 2 C 0 3 o-5 % ; No. 2, HC 1 0-2 % ; No. 3, HC 1 0-5 %. 
After 24 hours’ digestion (40°C.) the results were: — 
1. 2. 3. 
fibrin unaltered partly gone gone 
tryptophane faint distinct faint 
o-2 grm. Witte-peptone now added to each bottle, and after 24 hours' further 
digestion the results were : — 
1. 
2. 
3 - 
fibrin 
unaltered 
gone 
gone 
tryptophane 
faint 
distinct 
marked 
Bottle No. 1 was further digested for 96 hours, when a marked tryptophane- 
reaction was obtained ; the fibrin remaining unaltered. 
This experiment brought to light the new and important fact that 
Nepenthes-Wqmd can effect peptolysis in an alkaline liquid. With a view 
to confirmation the following experiments were made. 
20 cc. of pitcher-liquid were put into each of 2 bottles, to each of which were 
added HCN to 0-2 %, Witte-peptone 0-4 grm., and o-i grm. of fibrin : the contents of 
both bottles were made alkaline to the extent of 0-25 in the one case, of 0*15 in the 
other. After 48 hours’ digestion the results were : — - 
0-25 Na 2 CO r O’ 1 5 Na 2 CO s . 
fibrin 
unaltered 
unaltered 
tryptophane 
none 
none 
after 48 hours’ further digestion : — 
fibrin 
unaltered 
unaltered 
tryptophane 
faint 
distinct 
In another similar experiment, I obtained distinct tryptophane-reactions in 
liquids containing 0*5 %, 1 %, and 1-5 % Na 2 C 0 3 after 144 hours’ digestion. 
