The Proteolytic Enzyme of Nepenthes (II). 
BY 
S. H. VINES. 
I N the Annals of Botany for December, 1897, I published 
a paper on this subject, in which I adduced a con- 
siderable amount of evidence to prove that, contrary to the 
opinions of Dubois and Tischutkin, the pitcher-liquid of 
Nepenthes contains a proteolytic enzyme. Since writing that 
paper I have continued my observations, of which I now give 
some account by way of supplement. 
Activity of Pitcher-Liquid. 
I have nothing to add that would in any way modify my 
assertion that I have never failed to obtain digestion of fibrin 
by the liquid in a relatively short time, provided that the 
liquid was duly acidified. My new observations refer to 
the effect of exposure to high temperatures, of treatment 
with alkalies, and of filtration of the liquid, upon its digestive 
activity. 
Heat . The following results will serve to illustrate the 
general effect of exposure to high temperatures. The method 
of experiment was to maintain the liquid for a given time at 
the required temperature, and then to institute a digestion- 
experiment, adding fibrin and the necessary acid ; in nearly 
[Annals of Botany, Vol. XII. No. XL VIII. December, 1898.] 
