1 8 Vines . — Tryptophane in Proteolysis . 
of milk, it is stated in a foot-note, that the author had ob- 
tained the tryptophane-reaction in a 7-hours’ digestion of 
fibrin with extract of pig’s stomach. It is not surprising that 
under such conditions of publication, this important discovery 
should have remained comparatively unnoticed. Malfatti (21) 
has also obtained tryptophane in neutral, acid, and weak 
alkaline digestions of Witte-peptone with pepsin : he ascribes 
the formation of tryptophane in the neutral and alkaline 
digestions to the presence of trypsin. Further, Glaessner (22) 
finds that in auto-digestion of gastric mucous membrane (3-4 
weeks) in a weak alkaline (Na 2 Co 3 ) liquid, tryptophane is 
formed. From this he infers that two enzymes are secreted 
by the stomach ; viz. true pepsin, and what he terms ‘ pseudo- 
pepsin,’ an enzyme which works in alkaline liquids that would 
destroy pepsin and in acid liquids that would destroy trypsin, 
and which, unlike true pepsin, forms tryptophane. On this 
hypothesis he accounts for the many discordant conclusions 
that have been arrived at as to the nature of the ultimate 
products of gastric digestion. 
Although the position of this question has been thus modi- 
fied since I began my observations upon pepsin, it is, I think, 
still worth while to place on record some of the experiments 
in which I succeeded in detecting tryptophane. The pepsin 
used was that sold as ‘ pepsin, pure scales ’ : but I also obtained 
satisfactory results with glycerin-extract of pig’s stomach. 
Jan. 24, 50 cc. of solution of 0-2 °/ Q HCI, containing 0-5 grm. of 
pepsin, were placed in each of two bottles (1) and (2): 
(1) to this was added 1 grm. of moist fibrin, J placed in incu- 
(2) to this was added 0-5 grm. of Witte-peptone, j bator at 4 p.m. 
Jan. 25, 11 a.m., no tryptophane in either: added 0-5 grm. of 
pepsin to each; also 1 grm. of fibrin to (1), and 1 grm. of Witte- 
peptone to (2). 
4 p.m., faint tryptophane-reaction in both : added more fibrin to 
(1), and more Witte-peptone to (2). 
Jan. 26, 10 a.m., both gave faint tryptophane-reaction: filled up 
both bottles with 0-2 °/ Q HCI solution. 
Jan. 27, 11 a.m.. tryptophane-reaction marked in (1), strong in (2). 
