150 
Vines.- — The Proteases of Plants (//). 
I felt sure that the points of divergence between his results and mine — such 
as the slowness of the digestive action on fibrin that he observed, and the 
relatively small production of amido-acids and hexon-bases — could be 
accounted for by some or all of these differences of method ; and experi- 
ment has largely realized this anticipation. The method I adopted was 
to institute comparative experiments with papains derived from several 
sources, with acid and alkaline liquids, and with toluol and HCN as anti- 
septics. The quantity of fibrin used was both relatively and absolutely 
small. The following description of an experiment will make the method 
clear. 
Fibrin-Digestion . Three samples of papain were used, obtained respec- 
tively from Messrs. Christy, Finkler, and Merck. 
4 grms. of each sample of papain were mixed with i6oc.c. of distilled water, and 
after standing for some time were strained through muslin : the liquids obtained were 
turbid, and gave no tryptophane-reaction ; the Christy and Merck liquids were slightly 
acid, the Finkler liquid neutral. 
The 160 c.c. of each papain-liquid were put into four bottles, 40 c.c. in each, and 
were further treated as follows : — 
No. 1, added toluol to 1%, and citric acid to 0*5 % 
» 2, „ „ „ Na 2 C 0 3 „ 0.75 % 
» 3 , „ HCN to 0-2%, „ citric acid,, 0-5% 
„ 4, „ „ „ Na 2 C 0 3 „ 0-75% 
The contents of Nos. 2 and 4 were distinctly alkaline, and remained so throughout 
the experiment. To each bottle -|grm. moist fibrin was added. There were thus 
twelve bottles in all put to digest in the incubator at about 40° C. 
After 18 hours" digestion, the effect upon the fibrin was as stated below : — 
(1) Toluol acid. (2) Tol. alk. (3) HCN acid. (4) HCN alk. 
Christy not gone not gone gone gone 
Finkler not gone not gone not gone nearly gone 
Merck not gone not gone partly gone gone 
Four hours later the fibrin had completely disappeared in the Finkler bottle No. 4. 
After 24 hours" digestion the state of the fibrin was: — 
No-. 1. 
No. 2. 
No. 3. 
Christy 
not gone 
not gone 
— 
Finkler 
not gone 
not gone 
nearly gone 
Merck 
not gone 
not gone 
nearly gone 
hours" digestion the results were 
No. 1. 
No. 2. 
No. 3. 
Christy 
nearly gone 
nearly gone 
— 
Finkler 
going 
unaltered 
gone 
Merck 
going 
unaltered 
gone 
