Vines. — Proteolytic Enzymes in Plants (II). 6 13 
acid, and in the bottle to which neither citric acid nor HCN had been 
added ; marked in the bottle with citric acid but without HCN. 
48 hours later, the fibrin presented the same appearance, and the 
tryptophane-reactions were : — marked in all the bottles except the 
one containing HCN but no citric acid, where it remained distinct. 
I have further succeeded in preparing a proteolytically 
active glycerin-extract from the roots. 100 grms. of the root, 
cut into small pieces, were macerated in strong alcohol for 
twenty-one hours, and then dried at room-temperature : the 
dried material, which weighed only 13 grms., was well 
triturated with 50 cc. glycerin, and left to stand for three 
days. The mass was then strained through muslin, yielding 
a turbid brownish extract, the activity of which was tested as 
follows : — 
30 cc. of the glycerin-extract were mixed with 130 cc. chloroform- 
water, and 40 cc. of the mixture were placed in each of 4 bottles. 
To the liquid in No. 1, which was slightly acid, 0-2 grm. Witte-peptone 
was added: to No. 2, 0-2 grm. Witte-peptone, and 0-2 grm. citric 
acid (=o*5%): to No. 3, 0*2 grm. Witte-peptone and 0-2 grm. 
Na 2 C 0 3 (=0-5%) so that the reaction was distinctly alkaline: to 
No. 4 nothing was added. 
After 4 hours’ digestion at 40° C., the contents of Nos. 1, 3, and 4 
gave a faint tryptophane-reaction ; those of No. 2, a distinct reaction. 
19 hours later the tryptophane-reaction was distinct in No. 1, marked 
in No. 2, faint in Nos. 3 and 4. 
From these experiments it is clear that the tuberous root 
of the Dahlia contains an enzyme which proteolyses the 
proteids of the root ; that it also proteolyses Witte-peptone 
is shown by the rapid development of a more or less strong 
tryptophane-reaction when this material is presented to it. 
There is, however, no evidence that the protease attacks 
fibrin, for in no case did there appear to be any definite 
solution of it ; the tryptophane-reactions given by the contents 
of the bottles in the fibrin-experiments were so nearly the 
same as those given by the bottles in the autolysis-experiments 
that they do not appear to have been to any extent due to the 
presence of the fibrin. 
T t 2 
