464 Dr. A. Harden and Mr. W. J. Young. [Jan. 17, 
Expervments 19, 20, 21.—In each case 25 c.c. of yeast-juice +0°5 c.c. of 
0-3 molar arsenate + 20 c.c. of water or a normal solution of sodium hexose- 
phosphate (containing 8°5 grm. of the acid per 100 c.c.) were employed, the 
liquids being made up to 45°5 c.c. 
Total c.c. evolved in the time ¢. | 
Time after 
No. of addition 
: : a. b. c. 
experiment. of arsenate, in Ae eee 
minutés. ig ee rah ae Arsenate + a—b. Hexosephos- 
ier ter hate + water 
phate. we i P 3 | 
19 15 40 ‘5 26 °2 14 °3 6°3 
30 Gale a 50 °5 27 °2 12°1 
75 147 ‘9 90 °6 57 °3 22 3 
205 311 °7 165 ‘9 145 °8 55 °4 
ane mnresathee Rate in c.c. evolved in preceding 5 minutes | 
5 addition 
experiment. 
of arsenate. 
a. | b a—b Cc. 
hem, 
20 5 2°9 0°5 2 °4 1°4 
10 377 0°6 Sa 0:9 
15 3°7 O °4 3°3 0°8 
20 3°7 0°5 a aes SP 0:9 
i 25 3°9 0°3 3 °6 0:7 | 
30 3 °5 0 °4 31 0°7 | 
| Total.. 21 °4 ee ie 2:7 fom ae ft | ee | ee 8 °7 | 5 ‘4, 
| 21 5 9°1 3-0 6:1 3:1 : 
10 8°6 2°3 6°3 2°9 
15 7°3 HY) 54 0:9 
15 20 6°8 1°2 5 ‘6 1°2 
35 6°4 v1 23 Soak | 1°3 
40 6°9 nd, 5°2 1°6 
45 6:1 1°3 4°8 0°9 
50 5°6 1:0 4°6 0°8 
Total.. 56 °8 Meher | ome es [oe | et | ee 31 Pe 
It will be seen that in every case the fermentation in presence of hexose- 
phosphate and arsenate, less the auto-fermentation in presence of arsenate (a—b) 
is considerably greater (two to four times) than the rate of fermentation in 
absence of arsenate (c). 
As this. increased fermentation is carried on at the expense of the 
hexosephosphate, it follows that the hexosephosphate is being more rapidly 
