12 THE BEGINNINGS OF LIFE. 



such fermentative changes as are accompanied by the 

 de novo origination of living things. The above-men- 

 tioned apparently exceptional results are, therefore, 

 just as compatible with the notions of M. Liebig and 

 his school, as they are antagonistic to those of M. Pas- 

 teur. Certain simpler fluids do not undergo change, 

 whilst others of a more complex description, under the 

 influence of similar conditions, do ferment. 



The complete untenability of M. Pasteur's explana- 

 tions are, however^ best revealed by having recourse to 

 a series of comparative experiments, in which portions 

 of the same fluid are boiled for an equal length of time 

 in vessels of different kinds, and are subsequently sub- 

 mitted, in a water-bath, to the influence of the same 

 temperature. Owing to the different behaviour of the 

 same fluids under different conditions^ we are enabled 

 to draw some very important conclusions; but from 

 the different behaviour of different fluids under these 

 respective conditions, we are enabled tio eliminate 

 many of the explanations of M. Pasteur and others, 

 whilst at the same time facts are revealed of the most 

 decisive nature, bearing upon the relative merits of the 

 two doctrines as to the cause of fermentation and 

 putrefaction ^ 



Such experiments show quite conclusively that M. 

 Pasteur's explanations are altogether inadequate to 

 account for the occasional preservation of boiled fluids 

 in bent-neck flasks. The preservation^ far from being 



1 Appendix C is a record of experiments of this kind. 



