294 



L. D. BXJSHNELL 



cent of N/1 glacial acetic acid, giving the pH as shown in the 

 tables. 



Two centimeters of this acid broth were added to the tubes 

 which were then heated in the steamer for fifteen minutes and 

 cooled as rapidly as possible to remove air from the liquid. To 



TABLE 6 



Influence of varying amounts of salt and air upon thermal death point of B. suhtilis 

 spores. Original numbers of spores added 32,000,000 per cubic centimeter 



these tubes was added 1 cc. of a heavy suspension of spores sus- 

 pended in acid broth, similar to that in the tubes. The tubes 

 were then filled to the mark with similar broth and the volume 

 noted. Amounts equal to 5 per cent, 10 per cent, 25 per cent of 

 the total volume were removed from the tubes. They were 



