34 



H. J. Seaks 



compounds. The former seems to be the more probable of the two 

 hypotheses. Fortunately, this proposition is susceptible of proof; at 

 least, strong evidence for or against it may be obtained by investigating 

 the effect of glucose on the decomposition by micro-organisms of quan- 

 tities of creatin and creatinin added to peptone solution. 



TABLE 22 



The Decomposition of Creatinin by Bacteria 



Culture 



2 Days Old 



Glucose I Glucose 

 Present | Absent 



6 Days Old 



Glucose I Glucose 

 Present I Absent 



15 Days Old 



Glucose Glucose 

 Present Absent 



B. proteus-vulgaris 



B. pyocyaneus 



B. typhosus 



B. coli-communis 



B. subtilis 



B. faecalis-alkaligenes.. 

 Staph, pyogenes-aureus 

 B. dysenteriae, Shiga... 



B. acidi-lactici 



Sterile medium 



52.4 

 51.3 

 48.1 

 41.3 

 41.8 

 56.5 

 47.4 

 56.9 

 50.7 

 54.6 



47.1 

 53.3 

 53.9 

 56.2 

 64.2 

 54.1 

 13.4 

 53.6 

 45.2 

 54.6 



29.3 

 42.0 

 33.6 

 51.8 

 46.8 

 48.7 

 48.1 

 53.2 

 55.6 - 



31.9 

 38.3 

 42.4 

 44.6 

 53.6 

 55.5 

 Trace 

 51.4 

 32.7 

 55.5 



82.3 



* 



48.2 

 32.9 

 54.8 

 48.8 

 44.1 

 51.8 

 58.2 

 55.1 



32.3 

 Trace 

 50.0 

 Trace 

 57.1 

 52.2 

 Trace 

 51.6 

 34.8 

 55.3 



* The solution was too dark-colored to be comparable with the standard. 



An experiment similar to the one just described, but with a 2% peptone solu- 

 tion containing in each liter the juice from 1 lb. of lean beef as the medium 

 used, was carrried out. Only creatinin determinations were made. The same 

 method was used as in the former experiment. Samples of 2 c.c. were used for 

 most of the determinations. 



Table 22 gives the results of the test. As in all the preceding tables, 

 the values are given in milligrams per 100 c.c. of the culture fluid. 

 The data seem to be in accord with the explanation already suggested 

 of the effect of glucose on the formation of creatin and creatinin by 

 bacteria. The latter compound is decomposed in most cases to a con- 

 siderably less extent when glucose is present in the medium. The very 

 great eft'ect of this substance in the case of the staphylococcus cultures 

 is worthy of special mention. It is also interesting that the cultures 

 of B. faecalis-alkaligenes and of B. dysenteriae show the same absence 

 of the sparing effect of sugar as they did in the case of the peptone 

 solutions. 



Further experiments are now in progress on this phase of bac- 

 terial metabolism, and it is to be hoped that more definite information 

 may be obtained on the part played by glucose in these reactions. 



SUMMARY 



Peptone cultures of most bacteria give fluctuating concentrations 

 of amino-acid, showing that these bodies are formed and broken down 

 continuously by the organisms. 



