468 Dr. A. Harden and Mr. W. J. Young. [Jan. 17, 
| 1 | 2 | 2). | 4, | 5 
Initial rate (c.c. per 5 minutes) .................. 2°5 15 -8°5 1°9 100 
Ratg after MR OUR Cs ei sacide ds cl ee ee 1°4 2°9 1°6 72 
Rate after 1 hour 40 minutes... ............00000- — 1 * 1°85 135 4°45 
Total evolved in 1 hour 45 minutes... ......... = 27:0 81 °2 82 °4 141 -2 
It is to be noted, in the first place, that the rate in presence of glycogen 
(1:9) is less than in presence of sugar (2°5), so that the rate of fermentation 
in No. 4 is actually controlled by the rate of production of sugar. 
The effect of adding glycogen to the juice increases 
the total by (GSC) er tierce eee cientin ean seeee 324—27 = 5-4 cc. 
The effect of adding the arsenate to the juice alone 
increases the total by. (3)-(2) .............c.scce0 81: 2—27 9 = oa 
Sum of the separate effects of glycogen and 
ATSON ALG ade iss ote nie ve pele secede ere abies eros mericeate 642+ 54 = 596 ., 
Effect of adding glycogen. and _ arsenate | 
together (oye) t ics sccseabesenets te ser tec meee 141-2—27 =1147 ,, 
Hence at least 114:2—59°6 = 54°6 c.c. more carbon dioxide have been 
derived from glycogen in the presence of arsenate than in its absence. 
Comparing the rates per five minutes given in columns 3 and 5, showing the 
effect of arsenate on the fermentation in absence and in presence of added 
glycogen, it is to be noticed that the initial rates are not greatly different 
(8:5 and 10). This is due to the fact that at the commencement of the 
auto-fermentation there is an ample supply of glycogen. This, however, soon 
begins to fail, and consequently the rate falls off more rapidly than in the 
presence of added glycogen, the relative rates after 1 hour being 2°9 and 7:2, 
and after 1 hour 40 minutes, 1°85 and 4°45. For this reason the comparison 
is best made between the totals evolved after some time and not between the 
initial rates. 
Further evidence in support of the conclusion that the hydrolysis of 
glycogen is accelerated by the addition of arsenate is afforded by the effect of 
the addition of glycogen to Solutions 2 and 3 in the foregoing experiment, 
which had been allowed to auto-ferment in absence and presence of arsenate 
respectively. 
5 minutes’ rate before addition of glycogen ......... Lt 1°85 
- oe after \ pcre weeteeeoete ae cance 1 ‘4 4 °4 
