iv SPONTANEOUS GENERATION 289 



the intestines of animals originate where they are found ; 

 the belief still held in some rural districts in the occur- 

 rence of showers of frogs, or in the transformation of 

 horse-hairs kept in water into eels ; all indicate a survival 

 of this belief. 



As accurate enquiries into these matters were made, 

 the number of cases in which equivocal generation was 

 supposed to occur was rapidly diminished. It was not 

 surprising, however, considering the rapidity with which 

 Bacteria and Monads were found to make their appear- 

 ance in organic substances and infusions, that many 

 men of science imagined them to be produced abiogeneti- 

 cally. The rapid multiplication of these forms means, of 

 course, that a certain amount of fresh living protoplasm 

 has been formed out of the constituents of the hay- 

 infusion, through the agency in the first instance of a 

 single living Bacterium. The question naturally arises, 

 why may not the formation of protoplasm take place 

 independently of this insignificant speck of living 

 matter ? 



It must not be thought that this question is in any 

 way a vain or absurd one. That living protoplasm has 

 at some period of the world's history originated from 

 not-living matter seems a necessary corollary of the 

 doctrine of evolution, and is obviously the very essence 

 of the doctrine of special creation (p. 221) ; and there is 

 no a priori reason why it should be impossible to imitate 

 the unknown conditions under which the process took 

 place. But at present we are quite unable to solve this 

 fundamental problem. 



Experiments conducted with proper precautions, how- 

 ever, all tell the same tale : they prove conclusively that 

 in putrescible infusions that have been properly sterilised 



-i.e., thoroughly boiled so as to kill any organisms they 

 may contain and adequately protected from the 



PRACT. ZOOL. U 



