Vines .— The Proteases of Plants (VII). 219 
Experiment 5. Witte-peptone was dissolved to the extent of 0-5 % in a 0.5 % 
solution of the diastase: the slightly acid liquid, which filtered rather slowly, gave 
a trace of tryptophane-reaction, and, of course, a good biuret-reaction. 40 c.c. were 
put into each of 3 bottles: to No. 1 no acid or alkali was added; to No. 2, HC 1 to 
0-2 % ; to No. 3, Na 2 C 0 3 to 1-25 %. 
After 4 hours in the incubator, the tryptophane-reaction in Nos. 1 and 3 was as 
at the beginning; in No. 2 it had become marked. After 24 hours’ digestion the 
reactions were—strong in No. 1 ; very strong in No. 2 ; in No. 3 but little stronger 
than originally. The biuret-reaction was scarcely perceptible in Nos. 1 and 2, but 
was undiminished in No. 3. Similar results were obtained after 48 and 72 hours’ 
digestion. It was noticed that the acid reaction of No. 1 increased perceptibly during 
the experiment. 
It is thus shown conclusively that Taka-diastase contains active 
proteases which are especially adapted to an acid medium. The reaction- 
ranges for protein-digestion were not determined, but they appear to be 
wide : with a 0-5 % solution of the substance, fibrin-digestion took place 
readily between 0-4 % HC 1 and 1 % Na 2 C 0 3 ; and peptolysis within the 
same limits, though it was diminished by 1 % Na 2 C 0 3 and arrested (Expt. 5) 
by 1*25 % Na 2 C 0 3 . 
Some experiments were made with crude extract of the fungus, kindly 
placed at my disposal by Messrs. Parke, Davis and Co.; the results did not 
differ materially from those of the experiments here described, which were 
with the substance as prepared for sale, except that the digestive action 
was more rapid. 
The question as to whether the digestive action of Taka-diastase is 
due to one or to two proteases had next to be considered : here again the 
alcohol method was employed, with the result that it was found possible 
to obtain, by means of extraction with alcohol, a liquid which digested 
Witte-peptone but had little or no action on fibrin. 
Experiment 6. 1 grm. of crude Taka-diastase was treated for a couple of hours 
with 100 c.c. of 50 % alcohol, and then filtered; filtration was slow. The filtrate was 
evaporated to half its bulk at about 37 0 C., to get rid of some of the alcohol, and then 
diluted with distilled water to 105 c.c. 35 c.c. of the liquid were put into each of 
3 bottles : to No. 1, 0-2 grm. of fibrin was added; to No. 2, Witte-peptone to 0-5 % ; 
to No. 3, Witte-peptone to 0-5 % and HC 1 to about 0-06 %. The contents of the 
bottles gave a trace of tryptophane-reaction. 
After 24 hours in the incubator, the fibrin in No. 1 remained unaltered; the 
contents of No. 2 gave marked tryptophane-reaction, and those of No. 3 a distinct 
reaction. 24 hours later, the fibrin still remained unaltered in No. 1, and the 
tryptophane-reaction had become strong in No. 2 and marked in No. 3. 24 hours 
later, the fibrin in No. 1 was found to have been partly digested, and the liquid gave 
