DISINFECTION J3 Y HE A T 45 



spores are quickly killed by a temperature consider- 

 ably below that of boiling water. The exact thermal 

 death-point of a considerable number of the most 

 important disease germs was determined by the 

 writer in a series of experiments made in 1885. The 

 cholera germ and the micrococcus of pneumonia were 

 the least resistant of all those tested, and were de- 

 stroyed by ten minutes' exposure to a temperature of 

 130 Fahr. The typhoid bacillus was killed in the 

 same time by a temperature of 140. In general the 

 statement may be made as a result of my own experi- 

 ments and those of other investigators, that patho- 

 genic bacteria which do not form spores are killed by 

 ten minutes' exposure to a temperature of 140 

 Fahr. (moist heat), with the exception of the tuber- 

 cle bacillus, which requires a somewhat higher tem- 

 perature (160 Fahr.). The list of known disease 

 germs which are killed by ten minutes' exposure 

 to a temperature of 140 Fahr. (60 C.) includes the 

 bacillus of typhoid fever, of diphtheria, of bubonic 

 plague, of glanders, the micrococcus of pneumonia, 

 of erysipelas and puerperal fever, of boils and ab- 

 scesses, the spirillum of cholera and of relapsing fe- 

 ver. In addition to these known germs it has been 

 determined that the same temperature destroys the 

 infecting power of vaccine virus, and presumably of 

 smallpox virus, of hydrophobia virus, and of certain 



