BIOCHEMISTRY OF STREPTOCOCCUS HEMOLYTICTJS 



227 



is not a waste process resulting from growth but that it represents 

 a definite step in the metaboUsm of the organisms. In his 

 experiments amino acids did not accumulate in the medium 

 until after the organism had made its growth. In explanation 

 Waksman suggests two possibihties; either (1) the growing 

 cells utilized the amino acids as rapidly as the latter were formed, 





^min* s e/V ^ 



^ e 9 Hours 



Fig. 5. Experiment III; Culture (1); 1 Per Cent Glucose Broth 



or (2) the proteolytic enzyme necessary for their elaboration 

 appeared only in the later stages of growth. Attention has been 

 called to the fact that the curves of amino acid formation in 

 experiment III exhibit a rise at the sixth or the ninth hour which 

 would correspond to the findings of Waksman on the actino- 

 mycetes. Examination of the growth curves (figs. 2, 3, 4) at 

 this point shows that the maximum period has just been passed 

 and that the organisms are now multiplying at a diminishing 



