Vines. — Tryptophane in Proteolysis. 17 
Pepsin. 
In the paper (1) to which I have already alluded, I expressed 
the conviction that the vegetable enzymes therein referred to, 
and probably the proteolytic enzymes of all plants, are essen- 
tially ‘ tryptic ’ in their nature. I arrived at this conviction on 
the evidence of the tryptophane-reaction, and on the assump- 
tion, generally made, that the formation of tryptophane from 
proteids is characteristic of ‘tryptic/ as distinguished from 
‘peptic/ digestion. 
I felt, however, that it was necessary to test the validity of 
this assumption ; to determine experimentally whether or not, 
as a matter of fact, the formation of tryptophane affords an 
absolutely reliable distinction between these two modes of 
proteolysis. I had not been able to find on record any state- 
ment to the effect that tryptophane had been found among 
the products of peptic digestion : but I was aware of the 
conflict of opinion between the school of Hoppe-Seyler which 
denied, and the school of Kiihne which asserted, that the 
difference between peptic and tryptic digestion is absolute 
and fundamental. Lubavin was, I believe, the first to make 
this suggestion (15), and he did so in consequence of having 
found leucin and tyrosin among the products of prolonged 
peptic digestion (9-11 days). More recently Lawrow (16) 
has stated that he found leucin to be formed in a very pro- 
longed gastric digestion ( % months) ; and Salaskin (17) and 
Zunz (18) both assert that crystallizable, nitrogenous, but 
non-proteid substances are formed under these circumstances 
[see also Langstein (19)]. There seemed, therefore, to be 
some probability that tryptophane might be produced in 
peptic digestion, a probability which has been realized in the 
investigation that I have made. 
It is not necessary, however, that I should give a full 
account of my experiments; for, when they were complete, 
I happened to discover that their results had been anticipated ; 
they are, therefore, merely of confirmatory interest. In a 
paper by Winternitz (20), on the chemistry of the putrefaction 
C 
