. Co- 
Zymin ; Phosphate,| Hexose- | Arsenate, 
JE suspension. ies Rote | nucicee 0°3 molar. | phosphate. | 0°3 molar. Gasyenches 
| HE c.c. C.c. grm. ¢.c. c.c, C.c. C.c. hrs. mins. 
el Gsca 10 20 1 2 0 0 0 7 in 24 
ae. 10 20 0 2 10 0 0 G7 hae 
3 10 20 0°75 2 0 0 0°25 O25; a 
te Fe 10 20 0 2 0 0 1 2°7 ,, 24 
lege) 10 20 0°25 2 0°5 0. 0°25 51°6 ,, 24 
te bre Palle yf) 20 6°3 0°7 0 0 0 1°5.,, 219 
bees 10 20 0 Ow 0 6°3 On) | 1827 es 
ia 3 10 20 6°3 0°7 0 0 0°5 dL, =< ons see 
| 4 10 20 0 0-7 0 63) | 085 133-5 je 
Seay at 10 15 0 0°5 0 0 0-2 2°0 ,, 20 
ote 10 15 8°8 0°5 0 8 °8 0 25°81.) aha 
| 3 10 15 0 0°5 0 8°8 0:2 Ad 8, yet hee 
| 
462 Dr. A. Harden and Mr. W. J. Young. [Jan. 17, 
the following way. A mixture of ferment and co-ferment can be prepared 
as previously described, which is free from phosphate and hexosephosphate,* 
and will not ferment sugar without the addition of phosphate. If now 
arsenate can replace phosphate, such a mixture should be rendered active by 
the addition of arsenate as well as by that of phosphate. 
In order to realise these conditions zymin was freed from phosphates: and 
co-ferment by repeated washing with water, until it was incapable of 
fermenting sugar. To this was added a solution of co-ferment, free from 
mineral phosphates and hexosephosphate, as previously described. This 
mixture was almost incapable of fermenting sugar, whilst the addition of 
phosphate, either in the form of mineral phosphate or hexosephosphate, 
readily caused fermentation. When, however, arsenate was substituted for 
the phosphate no fermentation ensued. This was not due to any inhibiting 
action of the arsenate, as in the presence of phosphate the same quantity of 
arsenate did not interfere with the fermentation. 
The hexosephosphate solution used was 0:21 molar for Experiment 17 and 
0:14 molar in Experiment 18. 
It will be seen that in no case was arsenate able to take the place of | 
phosphate, and it must therefore be concluded that the action of arsenate is 
fundamentally different from that of phosphate. 
Incidentally the foregoing experiments afford further evidence that 
phosphate is indispensable for the alcoholic fermentation of sugar. 
Comparing Nos. 1 and 2, Experiment 17, it is seen that in the almost 
complete absence of available phosphate only 1°5 c.c. of carbon dioxide were 
* “Roy. Soc. Proc.,’ B, 1908, vol. 80, p. 322. 
