38 BULLETIN 782, IT. S. DEPARTMENT OP AGRICULTURE. 
the future. 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 particular value in the study of bacteria which fail to ferment 
the usual test substances, such as carbohydrates, alcohols, and starches. 
