570 Vines. — Proteolytic Enzyme of Nepenthes (II I). 
tryptophan-reaction. The following is an example of the 
experiments : — - 
A mixture was prepared, consisting of io grms. moist fibrin (pre- 
served in dilute glycerin), 50 c.c. of 0-3 per cent. HC 1 , and 50 c.c. 
pitcher-liquid (N. Master ■ stand) : this was placed in the incubator (temp. 
38-5° C.) at 4 p.m. : next morning at 10.30 a.m. most of the fibrin 
was found to have been dissolved : a portion of the liquid was poured 
off, boiled, and filtered : the filtrate gave a good tryptophan-reaction. 
The tryptophan-reaction is not, however, exclusively 
associated with the action of tryptic enzymes, for tryptophan 
has been found among the products of the disruption of the 
proteid molecule effected by boiling proteids with baryta-water, 
or by bacterial putrefaction. But in the absence of all sign 
of putrefaction, such as the odour of indol and skatol, in my 
experiments, it must be concluded that the production of the 
tryptophan was due to the action of the enzyme, and that 
nepenthin-digestion is tryptic in its nature. 
As might be expected, I have also obtained the tryptophan- 
reaction in liquids resulting from the digestion of fibrin by 
both Pine- Apple juice and papain. 
In order to further demonstrate the tryptic nature of 
nepenthin, I have made experiments as to its action on 
albumoses and peptones, using as the proteid material the 
preparation which is well known as Witte-peptone ; with the 
result that the digested liquid gives the tryptophan-reaction. 
The following are the details of one experiment : — 
A mixture was prepared consisting of 1 grm. Witte-peptone, 0-2 grm. 
citric acid, 10 c.c. dist. water, 40 c.c. Nepenthes-liquid: placed in 
incubator at noon, temp. 38-5° C.; next morning the liquid gave 
marked tryptophan-reaction. 
I have also found that Pine-Apple juice and papain, under 
similar conditions, produce tryptophan from Witte-peptone. 
All the digestion-experiments have been controlled in various 
ways ; such as using boiled fibrin, in which case the digestion 
is very much delayed ; or making blank experiments with 
boiled Nepenthes- liquid, or without any at all. 
My results make it apparent that the three enzymes, 
