120 PHYSIOLOGY OF THE BACTERIA. 



3. While infusions of hay are generally sterilized 

 by a temperature of 60° (140° Fah.) or more, pro- 

 longed during twenty-four hours, certain spores of 

 Bacillus seem able to endure a temperature of 70 

 to 80° (158 to 176° Fah.) during three or four 

 days without losing the power of germinating. 



By some experiments made with refrigerating 

 mixtures, Cohn has ascertained that the bacteria 

 are not killed by very low temperatures, acting 

 even during several hours, — 18° for example 

 (0° Fah.). But they are benumbed at a tempera- 

 ture of 0° (32° Fah.) and probably at a temperature 

 a little higher, losing the power of movement and 

 of reproduction, and consequently their action as 

 ferments. They preserve, however, their capacity 

 to resume their activity at a more elevated tem- 

 perature. 



Frisch has pushed the experiment still further 

 than Cohn. By the evaporation of carbonic acid, 

 he has produced as low a temperature as — 87° 

 ( — 123 a Fah.) in liquids containing bacteria, with- 

 out destroying the vitality of these organisms, 

 development having subsequently occurred of coc- 

 cos and of bacteria. Congelation, then, cannot 

 serve to destroy the organized ferments. 



Let us add, however, that if the passage to ex- 

 treme temperatures is too sudden, there is then an 

 alteration (destruction ?) of these organisms (Schu- 

 macher). 



Movement. — We would not have consecrated 

 a paragraph to the action of movement upon 



