19 
Vines . — Tryptophane in Proteolysis . 
No antiseptic was used ; but in view of the results obtained as to the 
inhibiting action of 0-2 °/ Q HC1 on Bacteria (p. 15), the result cannot 
be attributed to putrefaction. 
I may mention that in many experiments I used thymol as an 
antiseptic, but these were generally unsuccessful. It appeared that 
thymol arrested the action of the pepsin. I therefore had recourse to 
hydrocyanic acid (HCN). The following experiment shows that this 
weak acid promotes peptic digestion, when present in sufficient 
quantity. 
Jan. 22. 50 cc. of o-2 °/ b HC1, containing 0-5 grm. pepsin and 
2-5 cc. of 4°/ 0 HCN (= o-2 °/ 0 ), were placed in each of two bottles 
(1) and (2) : 
(1) to this were added 2 grms. moist fibrin, ) placed in incu- 
(2) to this was added 1 grm. Witte-peptone, / bator at noon. 
Jan. 23. distinct tryptophane-reaction in both. 
Jan. 24. strong reaction in both. 
The tryptophane-reaction was obtained more rapidly in this than in 
any other of the experiments. 
I have not had time to repeat my experiments in the light 
of Glaessner’s (22) hypothesis. But if an enzyme having the 
properties of his * pseudo-pepsin ’ were present in the pepsin 
that I used, it is clear that this pepsin should produce trypto- 
phane in an alkaline liquid : this, however, I have not found 
to be the case. 
Conclusions. 
The additional instances that I have now given of the pro- 
duction of tryptophane, selected as they are from various 
classes and from different parts of plants, bear out my pre- 
viously expressed opinion that the proteolytic enzymes of 
plants in general are essentially ‘ tryptic.’ This statement will 
at any rate hold good until definite evidence is adduced to 
prove the existence of a ‘ peptic ’ enzyme. Moreover, these 
enzymes, with the exception of that of putrefactive Bacteria, 
are all active in acid media. 
In view of the results obtained as to the action of pepsin, 
the question at issue has become a broader one. At first it 
related merely to the nature of the vegetable enzymes, the 
