606 Vines . — -Proteolytic Enzymes in Plants (//). 
24 hours later, the results were : — 
Acid 
A Ikaline 
Neutral 
HCN ; 
f fibrin as before 
l strong tryptophane 
[ fibrin as before 
(faint tryptophane 
( fibrin quite disintegrated 
(marked tryptophane 
Chlorof 
as before 
faint trypt. 
as before 
doubtful trypt. 
about half gone 
distinct trypt. 
NaF. 
mostly disintegrated 
faint trypt. 
as before 
doubtful trypt. 
mostly disintegrated 
faint trypt. 
The contents of all the bottles gave a good biuret-reaction at the 
close of the experiment. The alkaline bottles retained their reaction 
throughout. 
The results with fibrin not only serve to confirm those with 
Witte-peptone, but they give valuable information as to the 
nature of the action not only of the antiseptics but also of the 
reaction of the medium. With regard to the first point, it 
appears that neither chloroform nor NaF inhibits the peptoniz- 
ing action of papa'fn, but that they both (especially NaF) 
impede further proteolysis with the formation of tryptophane. 
With regard to the second point, it is clear that the presence 
of acid is altogether favourable, whilst the presence of alkali 
is as distinctly unfavourable, impeding even peptonization in 
the bottles containing either chloroform or NaF. 
These results suffice to make clear the reason of the failure 
to obtain the tryptophane-reaction in the experiments of 
Mendel and Underhill, and they establish the accuracy of my 
previous observations. They strikingly demonstrate the 
remarkably favourable effect of the presence of HCN upon 
the proteolytic activity of papain, as also the inhibitory effect 
of NaF. 
In view of these results, I thought it worth while to make 
comparative experiments with a number of the antiseptics in 
general use for these purposes. In the first series, Witte- 
peptone was the digestible material ; in the second, fibrin. 
Experiment with Witte-peptone. 
A clear solution (2 grms. in 200 cc. dist. water) of papain, and 
a clear solution of Witte-peptone (2 grms. in 200 cc. dist. water), were 
prepared : in the latter .1 grm. of citric acid was dissolved. 25 cc. of 
