24 North Carolina Agricultural Experiment Station 
These data, obtained from studies with bacterial parasites of plants, con¬ 
firm the idea that the concentration of hydrogen ions is an agent of great sig¬ 
nificance in cellular destruction at high temperatures. 
LITERATURE CITED 
(1) Wolf, Frederick A. and Shunk, I. V. Tolerance to acids of certain bac¬ 
terial plant patliogenes. Phytopatli 11: 244-250, 1921. 
(2) Pasteur, Louis. Studies on fermentation. London, 1879. 
(3) Clark, W. M. The influence of hydrogen ion concentration upon phys¬ 
iological activities of Bacillus coli. Sci. n. s. 41: 624, 1915. 
(4) Cohen. Barnett and Clark, W. M. The growth of certain bacteria in 
media of different hydrogen ion concentrations. Jour. Bact. 4: 409-427, 1919. 
(5) Bigelow, W. D. and Esty, J. R. The thermal death point in relation to 
time of typical thermophilic organisms. J. Infect. Dis. 27: 602-617, figs. 4, 
1920. 
(6) Weiss, H. The heat resistance of spores with special reference to the 
spores of B. botulinus. J. Infect. Dis. 28: 70-92, 1921. 
(7) Paul, T. Birstein, G. and Reuss, A. Einfluss der Neutralsalze and 
Temperatur auf die Disinfektionsgeschwindigkeit con Sauren. Biocliem. 
Ztsclir. 29: 249, 1910. 
