92 



while when grown in egg meat mixture according to Rettger (Journal 

 Bio. Chem., Vol., 13), this same bacterium produces profound changes, 

 giving indol, skatol, and amino acids. 



Also, the utilization of any of these simpler nitrogenous products 

 of hydrolysis depends upon the life history and the species of the bacteria 

 and of food material other than the nitrogen compounds; that is, carbo- 

 hydrates, salts, etc. Concerning the utilization of the amino acids, under 

 certain conditions the basic amino acids or diamino acids are used to a 

 greater extent as a source of nitrogen instead of the monoamino acids, 

 and the reverse may happen ; the monoamino acids are used more readily 

 and fail to appear in the final products. 



From our own work during the past year on bacterial metabolism, 

 unpublished data are at hand showing the utilization of the amino acids. 

 Lots of 500 c. c. of sterile milk were inoculated with pure cultures of B. 

 proteus, B. liquifaciens, B. subtilis, and B. megatherium. These lots of 

 inoculated milk were stored at room temperature for six months. The 

 nitrogen distribution was then determined, ammonia, melanin, amino 

 acids, etc. 



The following table shows the per cent, of monoamino and diamino 

 acids obtained upon hydrolyzing the milk before inoculation, also the per 

 cent, of the same amino acids after inoculation for six months. 



*Por cent, of total nitrogen. 



In Table I the relative proportion of the utilization of the two groups 

 of amino acids is shown for the four different bacteria. It will be noted 

 that the diamino acids are used in greater amounts than the monoamino 

 acids. 



Table II shows the per cent, of the total monoamino and diamino 

 acid nitrogen utilized by the four bacteria calculated from Table I. 



