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° 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 
