BIOCHEMISTRY OF STREPTOCOCCUS HEMOLYTICUS 



217 



to calculate the amount of glucose destroyed in the formation 

 of the acids. Assuming for the moment that the volatile fraction 

 consists entirely of acetic acid and the non-volatile fraction of 

 lactic acid, a calculation indicates that the total acidity of this 

 culture accounts for only 50 per cent of the glucose utilized. 

 Fred, Peterson, and Davenport (1919) were able in this way to 

 account for 90 per cent of the sugar utilized in their xylose 

 fermentations. The large discrepancy in the present experiment 

 may possibly be due to two factors, first to experimental error, 

 and second to the fact that another unknown non-volatile acid 

 is present in the fermentation mixtures. 



TABLE 3 

 Experiment I 



II. THE METABOLISM OF STREPTOCOCCUS HEMOLYTICUS 



Within the past few years evidence has been increasing which 

 indicates that bacterial metabolism and human cellular metabol- 

 ism have certain fundamental characteristics in common. We 

 are indebted principally to Kendall and his collaborators for our 

 more definite knowledge of the chemical activities of unicellular 

 organisms. Cellular metabolism consists of two distinct phases — 

 (1) the anabolic or structural phase, (2) the katabolic, destructive 

 or "fuel" phase. As m the case of man, bacteria obtain struc- 

 tural material from nitrogenous nutrients while the energy 

 requirements are best satisfied by carbohydrate substances. The 

 analogy may be extended farther to the well known physiological 

 principle that "Carbohydrates spare body nitrogen." In other 

 words, those bacteria which are capable of utilizing both carbo- 



