6 14 Vines— Proteolytic Enzymes in Plants (II). 
Helianthus tuberosus. 
I have already stated (1) that the tissue of the tuber of this 
plant proteolyses Witte-peptone. I have since ascertained 
that the expressed juice of the tuber proteolyses Witte- 
peptone, as also its own proteids. 
In view of the presence of inulin in this tuber, I thought it 
worth while to determine whether or not the inulin were 
accompanied by tyrosin, as is the case in the tuberous root of 
the Dahlia. I found that there was no such storage of tyrosin 
in this plant. 
The expressed juice is a brown, turbid, slightly acid liquid ; 
it gives the oxidase-reaction with guaiacum, and strong 
xanthoproteic reaction. On boiling there is a dense pre- 
cipitate ; the clear filtrate gives faint tryptophane-reaction, 
no biuret, only a faint Millon’s reaction, and none with 
Morner’s reagent for tyrosin, in striking contrast to the juice 
of the Dahlia-root. 
Crambe maritima. 
The etiolated shoots of the Sea-kale occurred to me as 
probably interesting material for investigation. The expressed 
juice is a yellow acid liquid, giving good peroxidase but no 
oxidase-reaction with guaiacum ; it also gives weak xantho- 
proteic and Millon’s reactions. A precipitate is formed on 
boiling ; the filtrate gives no biuret, but faint tryptophane- 
reaction. Digestion-experiments showed that autolysis is 
feeble, but the proteolysis of Witte-peptone is active. 
50 cc. of expressed juice, diluted with an equal vol. of dist. water, 
were placed in each of 4 bottles : to (1) only a little thymol was 
added ; to (2) a little thymol and 0-5 grm. Witte-peptone ; to (3) 
thymol, 0-5 grm. of Witte-peptone, and 0-25 grm. citric acid (= 0-5 %) ; 
to (4) 0*5 grm. Witte-peptone, 0*25 grm. citric acid, and HCN 
to 0-2 %. 
After 1 9 hours’ digestion at 40° C., (1) gave faint tryptophane-reaction ; 
(2) a strong reaction ; (3) and (4) a marked reaction. 
