BACTERIAL METABOLISM WITHIN THE BODY 677 



Legend : 



Reaction, indicates the amount of alkalinity developed in terms of normal 



alkalai per 100 cubic centimeters of culture. 



+ indicates the amount of acidity developed, in terms of normal acid 



per 100 cubic centimeters of culture, compared with suitable controls. 



Ammonia, The figures indicate the number of milligrams of nitrogen as ammonia 



developed in 100 cubic centimeters of media, compared with suitable 



controls. 



These qualitative and quantitative observations, illustrative of the 

 sparing action of utilizable carbohydrate for protein as a source of en- 

 ergy, together with the significance of this sparing action in terms of 

 important products arising from the use of protein, and their replace- 

 ment by innocuous compounds when carbohydrate is available, leads 

 logically to the generalization that "the significance of the action of 

 pathogenic bacteria, so far as is known, depends upon their utilization of 

 protein for energy." When carbohydrate is used for energy, the organisms 

 are potentially lactic acid bacteria in terms of their reaction products 

 (Kendall). 



The endotoxins, so-called, of bacteria are not considered in this dis- 

 cussion, which deals with the products of growth. It appears to be a 

 fact, however, that carbohydrate influences the composition of bacteria in 

 a striking manner. Thus, Cramer has analyzed the dried substance of 

 bacteria grown upon ordinary nutrient agar, and upon glucose agar of 

 otherwise the same composition, with the following results, expressed 

 in percentages: 



