VITALITY OF PUTREFACTIVE ORGANISMS. 201 



One bulb of the 5-hour group and one of the 6-hour 

 group also became turbid and flocculent within, but 

 without any scum upon the surface. As in the case of 

 the 8-hour bulb already mentioned, this appearance 

 of life was, I doubt not, due to stray germs of excep- 

 tional resisting power, which maintained themselves 

 unscathed in the infusions after their fellows had been 

 destroyed. 



By multiplied experiments of a similar character 

 executed subsequently, and fortified by others made in 

 a different way, all doubts as to the real ordeal to which 

 the germs had been exposed were set at rest. A flood 

 of light, moreover, was thrown upon the difficulties 

 recorded in the foregoing pages. Prior to the intro- 

 duction into our laboratory of the particular samples of 

 desiccated hay whose adherent germs had manifested 

 such extraordinary powers of resistance, infusions of all 

 kinds, even those of hay itself, were sterilized with ease 

 and certainty. But the old London, the old Heathfield, 

 the Gruildford, and the old Colchester hay brought a 

 plague into our atmosphere, and thus the infusions of 

 other substances, some samples of hay included, became 

 the victims of a pest entirely foreign to themselves. 

 The failure to sterilize cucumber, turnip, beetroot, 

 artichoke, melon, beef, mutton, haddock, herring, sole, 

 was plainly due to the fact that their infusions had been 

 prepared in an atmosphere, or brought into contact 

 with vessels, contaminated with germs which have been 

 here shown capable of resisting 240 minutes' boiling. 

 It is obvious from all this that to speak of an infusion 

 being rendered barren by such or such a temperature, 

 is simply to use words without definite meaning ; be- 

 cause the temperature at which any infusion is sterilized 

 depends upon the character and condition of the germs 

 which find access to it. The death-temperature, for 



