The Alcoholic Ferment of Yeast-Juice. 



405 



with the synthetical isobutyleneglycol of Nevole* which boils at 176° to 178°. 

 The yield obtained from sugar was, however, very small, and only amounted 

 to about - 2 per cent, after allowing for the losses involved in the extraction 

 of the compound. 



In view of the properties of the crude glycol described above, it would seem 

 advisable to re-examine Henninger's glycol, the constitution of which was not 

 experimentally examined. 



Tlie Alcoholic Ferment of Yeast-Juice. 



By Arthur Harden, D.Sc., Ph.D., and William John Young, M.Sc. 



(Communicated by Dr. C. J. Martin, F.R.S. Received December 8, 1905, — Read 



February 1, 1906.) 



(From the Chemical Laboratory, Lister Institute.) 



1. Effect of the addition of Boiled and Filtered, Yeast-juice on the Fermentation 

 of Glucose Produced by Yeast-juice. 



In the course of some experiments on the action of various proteids on the 

 fermentative activity of yeast-juice, it was observed that the alcoholic 

 fermentation of glucose by yeast-juice is greatly increased by the addition of 

 yeast-juice which has been boiled and filtered, either when fresh or after 

 having undergone autolysis, although this boiled liquid is itself incapable of 

 setting up fermentation. Thus, the total fermentation produced by yeast- 

 juice acting on excess of glucose is, as a rule, doubled by the addition of an 

 equal volume of the boiled juice, and a further increase is produced when a 

 greater volume is added, the sugar concentration being kept constant, t 



A similar observation was previously made by Buchner and RappJ in a 

 single experiment (No. 265). 



The following table embodies a few of the results obtained, the yeast-juice 

 being prepared aud the amount of carbon dioxide evolved being estimated by 



* « Compt. Rend.,' 1876, vol. 83, p. 65. 



t Harden and Young, Preliminary Note, 'Proc. Physiol. Soc.,' 1004, vol. 32, 

 November 12. 



% ' Ber.,' 1899, vol. 32, p. 2093. 



