THEOBALD SMITH AND DOROTHEA E. SMITH 



29 



paratyphoid, Calf 297, and Bacillus coli, Calf 302, Bacillus coli was 

 inoculated at the same time with and hours after the paratyphoid 

 bacillus to determine how long a growth period is required by the 

 primary culture before it becomes completely inhibitory. 



Table V shows that inhibition begins after 4 hours and is nearly 

 complete at 14 hours with one lot of bouillon. With another it is 

 not complete at 72 hours. This difference is probably due to the 

 degree of removal of the last traces of muscle sugar during the prep- 



TABLE V. 

 Effect of Age of Primary Culture on Inhibition of Gas Production. 



Age of primary culture before 

 second inoculation. 



Amount of gas 

 produced. 



Acid produced in open 

 arm. 



Acid produced in closed 

 arm. 



Bouillon 1,003. 



aration of the fermented (lactose) bouillon which controls the cloud- 

 ing of the closed arm. 



It has been observed in certain experiments in which the second 

 organism was introduced later than 4 days after the first, that in 

 those cultures in which gas production was not inhibited, as in the 

 hog-cholera group, the total quantity of gas produced was neverthe- 

 less not up to the usual amount. This observation led to the infer- 

 ence that perhaps here also the time element was a determining factor. 



