182 
Vines . — The Proteases of Plants (///). 
Hyacinthus or lent alls. 
In a previous paper ( 2 ) I stated that the bulb of the Hyacinth 
can peptolyse Witte-peptone (p. 251), and can digest fibrin in an alkaline 
medium (p. 254). More recently ( 4 , p. 316) I have shown that both 
peptolysis and fibrin-digestion were effected by a 2°/ o NaCl-extract of 
the bulb, but less actively in a liquid to which 01 °/ o HC1 had been added 
than in a liquid of natural acidity or slightly alkaline. I now give the 
results of new experiments made with the view of inducing differential effects. 
It may be explained that strong NaCl-extracts (3 parts of water 
to 1 of bulb) are so active, in both peptolysis and fibrin-digestion, that 
it is convenient to prepare them more dilute. 
50 grms. of mashed bulb were extracted for a couple of hours with 200 cc. 
2 % NaCl-solution : the liquid was then strained off through muslin, and was found 
to be slightly acid and to give a faint tryptophane-reaction. 4 grms. of Witte- 
peptone were added to it, and toluol to 1 %. 40 cc. of the mixture were put into 
each of 5 bottles, treated as follows: — No. 1, nothing added; No. 2, Na 2 C 0 3 to 
1*5 % ; No. 3, Na 2 C 0 3 to 2 % ; No. 4, HC 1 to 0-2 % ; No. 5, HC 1 to 0-4 % : to each 
bottle 0-3 grm. fibrin was added. 
After 24 hours digestion (40°C.) the results were : — 
1. 2. 3. 4. 5. 
fibrin gone gone gone partly gone unaltered 
tryptophane very strong strong strong marked faint 
The fibrin remained unaltered in No. 5 after further digestion for 48 hours : the 
tryptophane-reaction had then become distinct. 
These results show that an addition of H Cl to 0-4 °/ o is about the limit of 
acidity for both fibrin-digestion and peptolysis for an extract of this degree 
of concentration: but as the differentiation was inconclusive, I made 
another experiment with more dilute extract, and with stronger alkali. 
30 grms. of bulb were extracted with 200 cc. 2 % NaCl-solution, to which 4 grms. 
of Witte-peptone were added, and HCN to 0*16 % : 40 cc. were put into each of 
5 bottles, with 0-2 grm. fibrin, as follows: — No. 1, natural acidity; No. 2, Na 2 C 0 3 to 
2 % ; No. 3, Na 2 C 0 3 to 3 % ; No. 4, Na 2 C 0 3 to 4 % ; No. 5, HC 1 to 0-2 %. 
After 24 hours’ digestion the results were : — 
1. 2. 3. 4- 
fibrin gone gone gone unaltered 
tryptophane strong strong marked distinct 
after 48 hours’ digestion the results were : — 
5 - 
unaltered 
marked 
fibrin — — — partly gone unaltered 
tryptophane very strong strong strong strong very strong 
Conclusion : the limit of alkalinity for peptolysis had not yet been reached, but 
its retarding effect is clear : the limits of alkalinity and of acidity for fibrin-digestion 
