38 BULLETIN 782, U. S. DEPARTMENT OF AGEICULTUEE. 



the futui'e. No attempt has been made to group these cultures on 

 the basis of the accepted principles of classification. 



10. It is hoped that the results presented may give a clearer con- 

 ception of certain types of alkaline fermentation. Probably many 

 alkaline reactions presumed to be due to ammonia formation are in 

 reality the result of the oxidation of organic-acid salts to alkaline 

 carbonates. These alkaline fermentations, occurring as they may 

 with acid fermentations, greatly complicate the fermentation of 

 various test substances. This type of alkaline fermentation may 

 explain many obscure results which occur in bacteriological studies. 

 Furthermore, since organic acids are suitable sources of carbon for 

 many bacteria, they may serve as an extensive set of test substances 

 by means of which the physiological characteristics of bacteria may 

 be further studied. The fermentation of organic-acid salts should 

 be of particiilar value in the study of bacteria which fail to ferment 

 the usual test substances, such as carbohydrates, alcohols, and starches. 



