454 Dr. A. Harden and Mr. W. J. Young. [Jan. 17, 
(3) 5 c.c. of sodium arsenate, as above, and 2°5 grm..of glucose. 
(4) 5 c.c. of sodium phosphate equivalent to the arsenate added to (2), and 
yielding 0°1553 grm. of MgeP20;. 
The fermentations of 1 and 2 were then observed until the evolution of 
carbon dioxide from (2) was approximately equal to that from (1) + 35 cc., 
and the two liquids were then boiled and filtered and the weight of 
precipitate yielded by magnesium citrate mixture ascertained. 
Liquid (3) was allowed to ferment until a total of 713 cc. had been 
evolved, and was then boiled and treated as above. 
Finally (4), which was intended to demonstrate the different behaviour of 
phosphate, was allowed to ferment until the rate again became normal, 
and was then boiled and precipitated with magnesium citrate mixture. 
The following table shows the total weight of precipitate produced in 
each case by magnesium citrate mixture :— 
| 
See ae Total before Total after : 
Original juice. Added. ae ney hate Difference. 
| 0 0678 0 0 0678 0 -0678 0 
2 0 ‘0678 0 °2211 0 °2889 0 3007 +0°0118 
3 0 -0678 0 °2211 0 °2889 0 °3513 +0 0624 
4 0 ‘0678 0 °1553 0 °2231 0 °1025 —0 1206 
| 
These numbers clearly show that the whole of the arsenate remains 
precipitable by magnesium citrate mixture, even after prolonged fermentation, 
whereas the phosphate is converted into a non-precipitable form. 
This fact is, however, not sufficient to exclude the possibility of the 
formation of an arsenic analogue of a hexosephosphate, since this might be 
precipitable by magnesium citrate mixture. 
Experiment 4.—The precipitate obtained from another experiment con- 
ducted on similar lines to (2) was therefore carefully washed, dried at 100°, 
mixed with copper oxide, and submitted to combustion in a current of 
oxygen; 03621 grm. gave 0°0069 grm. of COs, corresponding with 
0°052 per cent. of carbon. A magnesium hexose-arsenate would contain 
15°3 per cent. of carbon, so that the result of this analysis shows that no 
appreciable amount of such a compound is present. The trace of carbon 
actually found was no doubt derived from occluded matter from the boiled 
yeast-juice in which the precipitate was produced. The arsenate therefore 
remains free throughout the fermentation. 
