408 Dr. A. Harden and Mr. W. J. Young. [Dec. 8, 



Table III. — Dialysis of Boiled Yeast-juice. 25 c.c. yeast-juice + 5 grammes 



glucose 4- toluene. 



No. 



"Water. 



Boiled 

 juice. 



Residue. 



Dialysate. 



Time. 



Carbon 

 dioxide. 





c.c. 



c.c. 



c.c. 



c.c. 



hours. 



gramme. 



1 



25 















48 



-253 









25 











48 



*561 













25 







48 



0-264 



2 



25 















48 



0-268 









25 











48 



0-497 













25 







48 



0-276 



3, 



25 















72 



113 









25 











72 



-334 













25 







72 



0-189 

















25 



72 



0-334 



4 



25 















48 



0-154 

















25 



48 



0-251 



3. Dialysis of Yeast-juice. 



The facts above detailed suggested the possibility of dividing yeast-juice 

 into two fractions by dialysis ; an inactive residue and a dialysate which, 

 although itself inert, would be capable of rendering this residue active. 



This was experimentally realised by filtering the juice through a Martin 

 gelatin filter.* 



This method of rapid dialysis was chosen because the yeast-juices at our 

 disposal lost their activity too rapidly to permit of the ordinary process of 

 dialysis through parchment being carried out. Either a 10- or a 7'5-per-cent. 

 solution of gelatin was used to impregnate the Chamberland filter and the 

 filtration was carried out under a pressure of 50 atmospheres. 



Only a portion of the juice placed in the filter was actually filtered, the 

 remainder being simply poured out of the case as soon as a sufficient quantity 

 of filtrate had passed through. The residue adhering to the candle, which 

 consisted of a brown viscid mass, was dissolved in water and made up to the 

 volume of the juice filtered. Glucose was then added and one portion 

 incubated at 25° with an equal volume of sugar solution and a second portion 

 with an equal volume of the filtrate or of a boiled juice, containing an equal 

 amount of glucose. Before incubation the carbon dioxide was pumped out of 

 all the solutions. The filtrate was invariably found to be quite devoid of 

 fermenting power, none of the enzyme having passed through the gelatin. 



* 4 Journ. Physiol.,' 1896, vol. 20, p. 364. 



