REGULATING FACTORS IN BACTERIAL METABOLSIM 



665 



to the different results with the two peptones. This is, no doubt, 

 due to an essential difference in the composition of the two prod- 

 ucts. Since Rettger has shown that certain bacteria do not 



TABLE 1 



Amount oj ammonia -produced in solutions containing different amounts of Witte's 

 peptone and 0.5 per cent sugar 



ORGANISM 



B. coli 



B. cloacae 



B. paracoli 



B. capsulatus 



B. typhi 



Uninoculated control 



AMOUNT OF NHs IN CGM. IN 100 CC. OF MEDIA* 



0.5% peptone 

 0.5% glucose 



5 days 7 days 



-0.17 



0.17 

 -0.51 



0.17 

 -0.68 



0.00 



0.17 

 0.51 

 0.00 

 0.17 

 0.00 

 0.00 



1.0% peptone 

 0.5% glucose 



5 days 7 days 



0.0 



0.17 



0.00 



-0.17 

 0.00 



0.34 

 0.68 

 0.17 

 0.51 

 0.00 

 0.00 



1.5% peptone 

 0.5% glucose 



5 days 7 days 



0.34 

 0.17 

 0.00 

 0.00 



0.68 

 0.85 

 0.17 

 0.34 

 0.00 

 0.00 



1.5% peptone 

 No glucose 



5 days 7 days 



0.34 

 1.02 

 0.85 

 0.85 

 0.17 

 0.00 



0.34 

 0.68 

 0.51 

 0.68 

 0.34 

 0.00 



* The data presented here were obtained from two distinct sets of tests run 

 on different occasions. In the first a five-day and in the second a seven-day 

 period of incubation was used. The effects of the different amounts of peptone 

 on the ammonia yield are brought out in both series. 



TABLE n 



Amount of ammonia produced in solutions containing different amounts of American 



peptone and 0.5 per cent glucose 



ORGANISM 



B. coli 



B. cloacae 



B. paracoli 



B. typhi 



B. capsulatus 



Uninoculated control 



AMOUNT OF NHj IN CGM. IN 100 CC. OF MEDIA 



0.5% 

 peptone 



0.5% 

 glucose 



7 days 



0.17 

 0.34 

 0.00 

 0.00 

 0.17 

 0.00 



1% peptone 



0.5% 



glucose 



7 days 



0.17 

 0.51 

 0.00 

 0.17 

 0.17 

 0.00 



u% 



peptone 



0.5% 

 glucose 



7 days 



0.34 

 0.68 

 0.17 

 0.17 

 0.68 

 0.00 



Control, 1% 

 Peptone, 



7 days 



2.04 

 2.38 

 1.19 

 0.51 

 1.70 

 0.00 



digest proteoses and peptones, it seems that the American 

 product is very likely richer in amino-acids and hence gives a 

 higher yield of ammonia in all instances. 



B. Effect of different concentrations of peptone and glucose and 

 phosphate on the metabolism of intestinal bacteria. Another index 



