332 BOTANICAL GAZETTE [way 
other means must be resorted to in order to obtain preparations 
of it free from the bulk of proteids, etc., in the tissue extracts. 
STUDY OF THE PROTEASES OF PHASEOLUS VULGARIS 
The beans used in the experiments to be described were of two 
sorts, the red kidney bean and the white medium field bean; there 
has been nothing to suggest that the proteases in these varieties are 
different, and in the records of experiments no mention will be made 
of which kind was used. 
Resting seeds.—The resting seeds were tested a number of times 
for proteases; the results always showed that the seeds contained an 
enzyme capable of hydrolyzing Witte peptone with the formation of 
tryptophan, but incapable of digesting the phaseolin of the seed. 
Later in this paper will be found a more detailed description of this 
ereptase. The record of a typical experiment is given here. 
Seeds of Phaseolus vulgaris which were known to germinate readily 
were ground to a fine meal, one gram of this powder placed in each 
of four test tubes, and further additions made as follows: 
No. 1—15°¢ H,O +toluol. 
No. 2—15°¢ H,O +toluol—boiled. 
No. 3—15°° H,0+toluol+o.38™ Witte peptone. 
No. 4—15°° H,0+toluol+o.38™ Witte peptone—boiled. 
All were corked, shaken, and kept in the incubator at 37-39° C. 
for forty-one hours. At the expiration of that time the contents of 
each tube were boiled, acidified with acetic acid, and filtered. The 
filtrates were then tested. : 
No. 1—no biuret, Millon’s, nor tryptophan reactions. 
No. 2—not tested. 
No. 3—strong tryptophan reaction. 
No. 4—no tryptophan reaction. 
Seeds soaked in water for twenty-four hours.—Seeds from the 
same lot used in the above experiment were soaked in distilled water 
for twenty-four hours, the hulls removed, and the cotyledons ground 
in a mortar and 1.5®™ of the paste tested in the same way a5 the 
dry bean meal, and with the same results. 
Seeds soaked jor forty-five hours.—The beans not used in the last 
experiment were soaked twenty-one hours longer, peeled, and the 
tests repeated, with the same results. 
