ORIGIN OF LO WEST OR GA NISMS. \ 9 



some of these processes, almost all are agreed. There 

 is, moreover, a very frequent association of particular 

 kinds of organisms with particular kinds of fermenta- 

 tion. Hence the assumption is an easy and a natural 

 one to many persons, that the organisms which are 

 invariably met with in some cases are the causes of 

 these fermentations,* although it is quite obvious that 

 the facts on which this view is based, are equally ex- 

 plicable on the supposition that the organisms are 

 concomitant results or products (due to new chemical 

 combinations) of the fermentative changes. In the one 

 case the fermentative changes are believed to be ini- 

 tiated by the influence of living organisms ; and those 

 who regard living things as the only true ferments, 

 for the most part also believe that living things are 

 incapable of arising de novo. They think that those 

 organisms which serve to initiate the changes in ques- 

 tion, have been derived from a multitudinous army 

 of omnipresent atmospheric germs, which are always 

 ready, in number and kind suitable for every emer- 

 gency. This is the doctrine of M. Pasteur and others. 

 On the other hand, fermentations and putrefactions 

 may be regarded as sets of chemical changes, which 

 are apt to occur in organic and other complex sub- 

 stances these changes being due either to the intrinsic 



* From this view the transition is also easy, though none the 

 less illegitimate, to the doctrine that all fermentations are caused 

 by organisms ; just as it has been easy to start, and find converts 

 for, the doctrine expressed by the phrase " omne vivum ex vivo" 

 The distinction between #//and some is only too often overlooked. 



C 2 



