FERMENTATION 29 



" I am myself so entirely convinced of the 

 accuracy of the results which Pasteur obtained 

 are they not within the daily and hourly experience 

 of everyone who deals with the sterilisation of organic 

 liquids ? that I do not hesitate to believe, if living 

 torulce or mycelia are exhibited to me in flasks 

 which had been subjected to prolonged boiling after 

 being hermetically sealed, that there has been some 

 fallacy either in the premisses or in the carrying 

 out of the operation. ... If the formation of 

 life, of living substance, is possible at the present 

 day and for my own part I see no reason to doubt 

 it a boiled infusion of organic matter, and still 

 less of inorganic matter, is the last place in which 

 to look for it." 



That is " the germ-theory." It is not a philoso- 

 phical theory of life, but a most practical doctrine, 

 that fermentation, decomposition, putrefaction, are 

 the act of the living dust of the air: that these 

 bacteria are not begotten by the fermenting liquid, 

 but come into it from outside : that a liquid, really 

 sterile, exposed to air really sterile, will remain 

 sterile for ever. Out of the many episodes of the 

 fight, take Pasteur's famous lecture, at the 

 Sorbonne, April 7, 1864. All Paris was there : 

 the huge amphitheatre was filled to overflowing : 

 he showed them his flasks, his sterilised broth : he 

 told them the history of the controversy, told it 

 with quiet grave conviction, and just a little touch 

 of scorn for his adversaries " There is no condi- 



