VITALITY OF PUTKEFACTIVE OEGANISMS. 135 



most effectual by the writer who urged the objection. 

 Other temperatures, higher than any previously em- 

 ployed, were at the same time said to ensure sponta- 

 neous generation. I exposed my infusions to these 

 newly -discovered efficient temperatures, but found that 

 they remained as barren as before. 



With regard, moreover, to the question of concen- 

 tration, it was shown that, owing to their gradual 

 vaporization, the infusions used by me were probably 

 unequalled in strength by those employed by any pre- 

 vious investigator. Some of these infusions remain with 

 me to the present hour. Concentrated by twelve 

 months' slow evaporation, and reduced to one-fifth of 

 their primitive volume, they still exhibit the purity of 

 distilled water. 



These results proved beyond a doubt that in the 

 atmospheric conditions existing in the laboratory of 

 the Eoyal Institution during the autumn, winter, 

 and spring of 1875-6, five minutes' boiling sufficed 

 to sterilize organic liquids of the most diverse kinds. 

 Among these may be mentioned urine in its natural 

 condition, infusions of mutton, beef, pork, hay, turnip, 

 haddock, sole, salmon, cod-fish, turbot, mullet, her- 

 ring, eel, oyster, whiting, liver, kidney, hare, rabbit, 

 barn-door fowl, grouse, and pheasant. Once properly 

 sterilized, and protected afterwards from the floating 

 matter of the air, not one of these putrescible infusions 

 ever manifested the power of generating by its own in- 

 herent energy putrefactive organisms of any kind. 



§ 2. Experiments of Pasteur, Roberts, and Cohn. 



During the investigation just referred to I confined 

 myself for the most part to animal and vegetable juices 

 in their natural condition — that is to say, extracted 



