Vines . — The Proteases of Plants (//). 153 
gave a distinct reaction before digestion. There were thus nine bottles in each 
experiment. 
The application of the tryptophane-test in comparative experiments requires 
some care in order to ensure that the maximal reaction is really obtained. The 
reaction of the liquid must be acid; and then the chlorine-water should be added 
gradually until a vol. equal to that of the liquid to be tested (I usually took 5 c.c.) 
has been used : after standing some minutes a second vol. of chlorine-water should 
be added, and if necessary a third vol., until further addition does not intensify the 
reaction, but only weakens it. I found that the maximum was generally obtained 
with about 2 vols. of chlorine-water : but sometimes with less, sometimes with more. 
The duration of the digestion was 48 hours : the Na 2 C 0 3 bottles remained 
alkaline throughout the experiment. The terms used in describing the intensity of 
the tryptophane-reaction are, as in previous papers, the following : faint, distinct, 
marked, strong, very strong. 
It must also be explained that the sample of Merck's papain used in this and 
subsequent experiments was not the same as that used in the previous experiments 
(see p. 150), but a fresh and apparently much more active sample. 
The resulting tryptophane-reactions were as follows : — 
A. Christy’s Papain. 
Acid. 
Alkaline. 
Natural. 
Toluol 
24 
hours 
none 
faint 
none 
fy 
48 
» 
none 
faint. 
none 
HCN 
24 
}y 
distinct 
none 
distinct 
48 
>) 
marked 
none 
distinct 
NaF 
24 
>> 
faint 
none 
none 
>> 
48 
)> 
faint 
none 
faint 
B. 
Finkler’s 
Papain. 
Acid. 
Alkaline. 
Natural. 
Toluol 
24 
hours 
faint 
strong 
distinct 
jj 
48 
» 
distinct 
strong 
distinct 
HCN 
24 
>> 
marked 
faint 
distinct 
1) 
48 
a 
marked 
faint 
distinct 
NaF 
24 
>> 
faint 
distinct 
faint 
>> 
48 
faint 
marked 
distinct 
a 
Merck’s 
Papain. 
Acid. 
A Ikaline. 
Natural. 
Toluol 24 hours 
distinct 
distinct 
faint 
t) 
48 
f) 
marked 
distinct 
distinct 
HCN 
24 
>> 
marked 
faint 
distinct 
>5 
48 
marked 
faint 
distinct 
NaF 
24 
» 
marked 
distinct 
distinct 
)} 
48 
)) 
marked 
distinct 
distinct 
