570 Vines . — The Proteolytic Enzyme of Nepenthes. 
pletely disappeared, that in the control-tubes, though gela- 
tinous, showed no signs of breaking up or of solution. 
The pitcher-liquid used was obtained from N. Mastersiana , 
and I will begin the account of my observations by saying that 
in all the very numerous experiments which I have made, 
I have never once failed to obtain digestion of fibrin by the 
pitcher-liquid, provided that an adequate amount of acid, 
which I supplied in the form of a *25% solution of HC1, was 
present. I give the details of one experiment in illustration. 
Nov. 13, 1896. Two test-tubes were prepared, each containing 
5 c.cm. of neutral pitcher-liquid, and a shred of fibrin : to the one (A) 
5 c.cm. of -2 5°/ 0 HC1 were added, to the other (B) 5 c;cm. of distilled 
water : the tubes were placed in the incubator (about 35 0 C.) at 
11.30 a.m. At 2.30 p.m. the fibrin in tube A was completely dis- 
solved, the liquid giving a good biuret-reaction. The fibrin in tube 
B was still undissolved at 9 a.m. on the following morning: 5 c.cm. 
of • 2 5°/ 0 HC1 were then added to it, with the result that the fibrin had 
entirely disappeared by 11.30 a.m. 
In a similar experiment to the foregoing, made on May 7, 1897, 
with distinctly acid liquid taken direct from unopened pitchers, the 
fibrin in the tube (A) to which the HC1 had been added, dissolved 
within half an hour; whilst that in the other tube (B) showed no 
change after several hours. 
It is unnecessary to insist further upon the fact that the 
pitcher-liquid exerts an unmistakable solvent action on fibrin : 
the crucial point is whether or not it exerts this action under 
conditions such as to render highly improbable the assumption 
that the action in question is due to Bacteria rather than 
to a proteolytic enzyme. I have endeavoured to determine 
this point by making digestion-experiments in the presence 
of recognized antiseptics, with the following results :■ — 
Dec. 2, 1896. Prepared three test-tubes as follows: each tube 
contained some pitcher-liquid acidified with -2 5°/ 0 HC1, and a shred 
of fibrin: to (1) was added some potassium cyanide; to (2) some 
thymol ; to (3) a few drops of chloroform : at 1 p.m. the tubes were 
placed in the incubator at 35 0 C. The fibrin in tube (1) was com- 
pletely dissolved by 5 p.m. ; that in the other two tubes was broken 
