J. RUSSELL ESTY 



299 



out by Bigelow/ They are not parallel to each other, indicating that solutions of dif- 

 ferent chemical composition bear no definite relationship to the heat resistance of 

 bacterial cells. However, the two phosphate solutions appear to be related, and this is 



CHART II 



Q 10 20 30 40 50 60 10 60 



TlMt IN MINUTE.5 



confirmed by other results which are given in this same article.^ Data secured in this 

 manner makes it possible to establish standard type curves for a given number of 

 spores in a given solution by determining percentage survivals for at least four well- 

 selected times on a large number of tubes (one hundred to three hundred each time). 

 Such a curve can be used as a type to determine the effect of different numbers of 

 spores in the same solution or the influence of varying hydrogen-ion concentration in 



J Bigelow, W. D.: /. Infect. Dis., 29, 528-36. 1921. 

 ' Esty, J. R., and Williams, C. C: ibid., 34, 516, 1924. 



