Vines. — The Proteases of Plants (//). 151 
after 68 hours’ digestion : — 
No. 1. 
Christy gone 
Finkler nearly gone 
Merck gone 
No. 2. 
gone 
unaltered 
unaltered 
after 92 hours’ digestion the final results were : — 
No. 1. No. 2. 
Finkler gone unaltered 
Merck — swollen, but not digested. 
From these observations it may be concluded that: — 
(1) the action on fibrin of these different samples of papain was not 
uniform, Christy’s proving to be the most active ; 
(2) the action was much slower in the presence of toluol than in the 
presence of HCN ; 
(3) in the presence of HCN, the action was on the whole more rapid 
in the alkaline than in the acid liquid ; whilst in the presence of 
toluol it was more rapid in the acid than in the alkaline. 
These conclusions afford the explanation why Emmerling found the 
process of digestion to be so slow in his experiments. It was slow (1) 
because he used Merck’s papain and in relatively small quantity ; (2) because 
he used toluol as the antiseptic ; and (3) because the reaction of the 
digesting liquid was alkaline. It is clear, from the observations given 
above, that this was a singularly unfortunate combination of conditions, 
inasmuch as Merck’s papain, though active enough under other circum- 
stances, proved to be altogether inert in an alkaline liquid containing 
toluol, although in my experiment the amount of fibrin to be digested 
was relatively small. 
The other point noted by Emmerling — the smallness of the amount of 
amido-acids, &c., formed in his digestion-experiments — remains to be con- 
sidered. With this in mind, I made some observations by means of the 
tryptophane-method from time to time during the progress of the fibrin- 
digestion, with the following results : — - 
T vyptophane-reactions. 
After 20 hours’ digestion : — 
No. 1. 
No. 2. 
No. 3. 
No. 4. 
Christy — 
— 
marked 
distinct 
Finkler — 
— 
— 
distinct 
Merck — 
— 
— 
faint 
after 44 hours’ digestion : — 
Christy — 
marked 
distinct 
Finkler — 
— ■ 
distinct 
strong 
Merck — 
— 
distinct 
distinct 
