CITRIC ACID FERMENTATION 349 



there is for the statement that the hypothetical intermediate 

 product, glycolic acid, actually is produced from sugar. 



All in all there is no wonder that the real nature of sugar 

 catabolism has remained a secret thus far, locked in the 

 depths of the economy, when we have never been able to 

 satisfactorily explain processes like alcoholic fermentation 

 and the various types of acid fermentation, which have been 

 known so long, which are completed in the greatest quanti- 

 ties in vitro, and which are so favorable to objective study. 



