1905] DEAN—PROTEOLYTIC ENZYMES 23 
The corked tubes were kept in the incubator for six days. At the 
expiration of that time each digestion was boiled, acidified with a 
couple of drops of acetic acid, and filtered. Ten cubic centimeters 
of each filtrate were removed to a clean tube, and, after the addition 
of 5° of 10 per cent. sodium hydroxide solution, dilute copper sul- 
phate solution was added to the maximum biuret reaction. After 
standing for several minutes the intensity of the biruet reactions was 
compared. The comparison showed that a marked digestion of both 
proteose mixtures had taken place, the one from phaseolin being rather 
more vigorously attacked. The unboiled digestion with Witte pep- 
tone gave a tryptophan reaction with bromine water, the other 
unboiled digestion did not. 
Several trials were made of the digestibility of the acid phaseolin 
prepared by heating phaseolin for a few minutes with dilute sul- 
phuric acid. The results obtained indicated that the enzyme of the 
seed had, at the most, but a feeble action on this body. 
Various observers have shown that the antiseptics used in enzyme 
experiments may exert an inhibiting effect on the action of the fer- 
ment. Vines demonstrated that in papain digestions where sodium 
fluoride is used the action goes but little beyond the stage where — 
albumoses and peptones are formed; whereas with other antiseptics, — 
hydrocyanic acid for example, a marked formation of amido-acids  _ 
= takes place as shown by the production of tryptophan. It might be 
= argued that the toluol used throughout the experiments with Phase- 
: lus had an inhibiting action on the enzyme, so that it was unable wo 
= attack the proteids of the seed and could only act on albumoses and 
: Peptones. pee two following experiments were Saint: out to settle a 
that point: ae 
dons ut I eT hity-kve grams of finely une cotyle 
from six-day old bean seedlings were extracted for one and a 
hours with 175°° of water. The extract was ‘filtered nearly 2 
through pulp filters and then forced through ae -Pasteur- oe 
a filter into a sterile flask. Three portions of 25°° each 
: ted with a sterile pipette into three small sterile flasks. ne 
no. 1 “pal further was added; to no. 2 was added 0 0.07 * - 
