ORIGIN OF LO WEST OR GA NISMS. 9 5 



be, such fluids ought always to have undergone fer- 

 mentation. 



Whilst I have found that any given fluid, whose 

 strength is about equal on different occasions, acts in 

 a definite manner when the flask is hermetically 

 sealed after expulsion of all its air and during the 

 continuance of ebullition ; and, whilst a like definite 

 result can generally be obtained, when calcined air 

 is admitted to the boiled fluid before the vessel is 

 hermetically sealed ; it is found, on the other hand, 

 that the result is in no way predicable when uncal- 

 cined air is admitted. Sometimes fermentation takes 

 place, and sometimes in other flasks sealed at the 

 same time, and subsequently placed under the same 

 conditions no change whatever occurs. My own 

 experience in this respect accords perfectly with that 

 of M. Pasteur.* He, however, at once came to the 

 conclusion that the only inference from such facts 

 was that " germs " are not so universally distributed 

 as they had been supposed to be by Bonnet and 

 Spallanzani.t The unprejudiced inquirer, however, 

 will perceive that M. Pasteur was entitled to come to 

 no such conclusion concerning germs which was not 

 equally applicable to minute fragments or debris of 

 organic matter floating in the air. And, similarly, 

 the evidence which he adduces with regard to the 

 diminution in the number of the fertile flasks when 

 they were filled with some of the still air of the caves 



* Loc. cit. p. 71. t Loc. cit. pp. 75 and 76. 



