472 Dr. A. Harden and Mr. W. J. Young. [Jan. 17, 
(6) Arsenite accelerates the rate of hydrolysis of glycogen, and hence the 
auto-fermentation of yeast-juice. 
Experiment 29.—The following solutions were incubated and the rates of 
fermentation observed :— 
1. 20 cc. of yeast-juice from well-washed yeast+14 c.c. water. 
2. 20 c.c. of the same juice+9 c.c. water+5 c.c. of 0°3 molar arsenite. 
Experiment 30.—In this case 25 c.c. of yeast-juice were used along with 
(1) 15 cc. of water; (2) 10 cc. water and 5 c.c. of 0°3 molar arsenite. 
Auto. + water. Auto. + arsenite. 
Experiment. tht. D 
EUILE Rate in 5 Rate in 5 
ae Total. : Total. 
minutes. minutes. 
29 os 0°6 0°6 2°6 2'6 
10 0°5 Pak 2°2 4°8 
15 0°8 1°9 2°2 0 
20 0°5 2 °4 2 °4 9 °4 
60 0°55 6°8 2°6 26 °7 
30 5 0:9 0:9 4°5 4d 
10 1°0 1°9 4°0 8°5 
15 1°0 2°9 — — 
20 1 °4 4°3 3°8 16°1 
60 1°3 9°8 4°3 33 °5 
That this increase is, at all events in part, due to an acceleration of the 
rate of hydrolysis of glycogen is shown in precisely the same manner as 
for arsenate (Experiment 15). The results obtained are as follows :— 
Experiment 31.—Five quantities of 25 c.c. of yeast-juice were incubated 
with the following solutions and the fermentations observed :— 
1. 0°5 grm. glucose in 15 c.c. solution. 
2. 15 cc. water. 
3. 10 cc. water+5 e.c. of 0°3 molar arsenite. 
4, 0°5 grm. glycogen in 15 c.c. solution. 
5. 0°5 grm. glycogen in 10 cc. solution+5 c.c. arsenite. 
1 | 2 | 3. | 4 | 5 
Initial rate (c.c. per 5 minutes) ... 3°0 1°3 4°0 1°6 4°2 
Total evolved in 5 hours ............ — 67 °8 118 °3 T3°7 152 °1 
Here, as in the experiment with arsenate, the rate in presence of glycogen 
(16) is less than that in presence of glucose (3:0), so that the rate of the 
fermentation in (4) is actually controlled by the rate of production of sugar. 
