H4 



THE MICROSCOPE. 



ture again in order to kill them. Mr. Miquel, however, formally 

 attacks this method, as he considers it inefficacious, owing to the 

 uncertainty that exists in regard to the exact period of evolution of 

 certain germs. He also recommends operators not to rely upon the 

 limpidity of the liquors as a test of their sterilization; for there are 

 liquors, Cohn's for example, which are not deprived of active germs 

 after an ebullition of four hours at a temperature of ioo°. 



A(i 



JJ • ■■:■•.: v. '«V< 



J) v '■ C — ^ \Vn 

 — -vl> V, 







Fig. 4. 



It results from experiments that have been made that beef 

 broth, neutralized by potassa and kept for two hours at a tempera- 

 ture of no in closed vessels, remains indefinitely sterile. Some- 

 times, a temperature of 150 ought to be reached or even exceeded, 



