226 



LAURENCE F. FOSTER 



From the results of this experiment it seems evident that acid 

 formation is closely associated chronologically with growth and 

 active metabolism of the streptococcus. In each of the three 

 cultures we find the maximum period of acid production corre- 

 lated with maximum rates of growth, and of glucose utiUzation. 

 These results are not in accordance with the findings on pneu- 



Hi 



cells 



J^ 



Ho u rs 



Fig. 4. Experiment III. Culture (3) ; 1 Per Cent Glucose, 5 Per Cent Horse 

 Serum Broth (Laboratory Strain) 



mococci by H. M. Jones (1920) who reported a maximimi period of 

 growth correlated with slow acid formation, whereas the maxi- 

 mum period of acid production occurred during the time when 

 the organisms were multiplying at a diminishing rate. 



In a study of the nitrogen metabolism of actinomycetes, 

 Waksman (1920) concluded that the production of amino acids 



