4 
Vines. — Tryptophane in Proteolysis. 
As a rule the tryptophane-test was applied directly to the 
digestion-liquid, after ascertaining that the reaction of the 
liquid was acid. When the liquid was too thick, it was 
previously filtered. In cases in which a comparison had to 
be instituted, and where the result appeared to be at all 
doubtful, measured quantities of the liquids were tested, and 
measured quantities of chlorine-water added. 
In the more prolonged experiments it was advisable 
to use an antiseptic, and for a time I had recourse to thymol. 
But I found that this substance seemed to interfere with 
proteolytic action, especially in the case of pepsin ; so I re- 
placed it by hydrocyanic acid (HCN), adding a few drops 
of a strong (Scheele’s = about 4 °/ o ) solution ; and found that 
it not only acted as an antiseptic, but in certain cases pro- 
moted digestion. When using HCN, it was necessary to 
keep the liquids during digestion in stoppered bottles to 
prevent loss of the volatile acid. 
Bromelin. 
This is the proteolytic enzyme of the Pine- Apple ( Ananas 
sativus ) Schult.). We owe our knowledge of its properties 
mainly to the researches of Chittenden ( 3 ), who ascertained 
that it causes the formation of leucin and tyrosin ; it is there- 
fore a ‘ tryptic ’ ferment, a conclusion confirmed by the fact, 
to which I have already called attention, that tryptophane 
is another product of its activity. By means of the weighing 
method, to which I have alluded, Chittenden found that 
bromelin is most active in neutral liquids, ‘ but that the 
presence of small amounts of acid, especially such as are 
contained in Pine-Apple juice, and of sodium carbonate (*25 °/ 0 ), 
interferes with the proteolytic action only slightly.’ It is also 
a very active enzyme, the most active that I have yet met 
with in plants. Chittenden estimates that, in a neutral liquid, it 
digested in 2 hours over 20°/ o per cent, of the albumin supplied, 
and I have detected the tryptophane-reaction in a bromelin- 
digestion, whether of fibrin or of Witte-peptone, in 2 hours, 
in almost all cases. 
My results indicate that bromelin is an enzyme adapted 
