1905] DEAN—PROTEOLYTIC ENZYMES 333 
Seeds soaked twenty-jour hours and germinated in sand three days. 
—At this stage the hypocotyls were about one inch long. The 
cotyledons were removed, ground in a mortar, and the paste tested 
as in the previous experiments. The result was the same, the Witte 
peptone was attacked and the seed proteids were not. 
Seeds soaked twenty-jour hours and germinated six days.—The 
cotyledons from the young plants with hypocotyls two to three inches 
long were removed and ground to a paste. One gram of this was 
placed in each of six test tubes and other additions made as follows: 
No. 1—10°¢ H,O + toluol. 
No. 2—10°¢ H,O + toluol—boiled. 
No. 3—10° H,O+0.1 per cent. of citric acid +toluol. 
No. 4—10°¢ H,O+0.1 per cent. of Na,CO, + toluol. 
No. 5—10°¢ H,O0+0.2™ Witte peptone +toluol. 
No. 6—10°¢ H,O+0.22™ Witte peptone—boiled + toluol. 
After nineteen hours in the incubator the contents of each tube were 
iled, acidified, filtered, and the filtrates tested with these results: 
No. 1—no tryptophan nor biuret reactions, Millon’s ? 
No. 2—not tested. 
No. 3—no tryptophan reaction, biuret ? Millon’s? 
No. 4—no tryptophan reaction, biuret ? Millon’s? 
No. 5—strong tryptophan reaction. 
No. 6—no tryptophan reaction. 
Seeds soaked twenty-four hours and germinated ten days in the dark. 
—The cotyledons at this age of the plant were comminuted and tested 
in tubes as follows: 
No. 1~ground cotyledons + H,0 + toluol. 
No. 2—ground cotyledons +H, Ce cies egg albumen. 
No. 3—ground cotyledons + H,O + toluol + edestin. 
No. 4—ground cotyledons + H,O +toluol+ Witte peptone. 
After eighteen hours in the incubator the tests showed that only the 
Witte peptone had undergone proteolysis. 
Cotyledons of eleven-day old seedlings grown in light.— Beans 
allowed to germinate in washed sand, with a good supply of light, 
for eleven days had attained a height of five to six inches and had 
two well developed leaves besides the shriveled cotyledons. The 
cotyledons were found still to contain an active ereptase. 
