30 THE GERM THEORY OF DISEASE. 



6th. " The germs in milk, yelk of eggs and meat, after 

 having been boiled a short time, are still capable of being de- 

 veloped into the specific ferment of putrefaction, and some- 

 times, also, those of yelk ; at least, into long and indolent 

 vibriones. 



7th. " The specific ferment of putrefaction is of an animal 

 nature. It develops itself and multiplies at the expense of 

 albuminous compounds, but does not multiply under those 

 conditions alone which supply all the requisites for vegetable 

 growth." (Sydenham Society's Year Book for 1862. An- 

 nalen der chemie u pharmacie, vol. 117.) 



PASTEUR. 



The next important advance may be best illustrated by the 

 labors of M. Pasteur, in his sealed-flask cultivations, although 

 he was not the first to employ this particular mode of study. 

 Shutzenberger mentions that this kind of cultivation was first 

 performed by Needham, in London, who published a work on 

 this subject in 1745, in which it seems that he maintained the 

 hypothesis of the de novo origin of infusoria. Spallanzani, a 

 celebrated Italian physiologist, took the matter up, which re- 

 sulted in a lengthy controversy, in which Spallanzani refuted, 

 by experiment, the conclusions of Needham. The contro- 

 versy turned on this point. Spallanzani was not satisfied with 

 heating the hermetically sealed flasks containing the infusion 

 for several minutes, merely the time required to cook a hen's 

 egg and destroy the germ, as Needham expressed it, but he 

 kept them boiling for an hour ; after which no infusoria were 

 found. (Shutzenberger on Fermentation, page 311.) 



The plan of Pasteur was practically this : He reasoned 

 that if he could grow the yeast plant in sealed flasks until all 

 gluten with which it was first connected could be certainly got 

 rid of, he could then study the plant in all its purity, and 



