x.] BIOGENESIS AND ABIOGENESIS. 229 



elation, of its constituent organic molecules, which are 

 then set free as infusorial animalcules. 



It will be perceived that this doctrine is by no means 

 identical with Abiogenesis, with which it is often con- 

 founded. On this hypothesis, a piece of beef, or a handful 

 of hay, is dead only in a limited sense. The beef is dead 

 ox, and the hay is dead grass ; but the <f organic mole- 

 cules " of the beef or the hay are not dead, but are ready 

 to manifest their vitality as soon as the bovine or herba- 

 ceous shrouds in which they are imprisoned are rent by 

 the macerating action of water. The hypothesis there- 

 fore must be classified under Xenogenesis, rather than 

 under Abiogenesis. Such as it was, I think it will 

 appear, to those who will be just enough to remember 

 that it was propounded before the birth of modern che- 

 mistry, and of the modern optical arts, to be a most 

 ingenious and suggestive speculation. 



But the great tragedy of Science the slaying of a 

 beautiful hypothesis by an ugly fact which is so con- 

 stantly being enacted under the eyes of philosophers, was 

 played, almost immediately, for the benefit of Buffon and 

 Needham. 



Once more, an Italian, the Abbe Spallanzani, a worthy 

 successor and representative of Kedi in his acuteness, his 

 ingenuity, and his learning, subjected the experiments 

 and the conclusions of Needham to a searching criticism. 

 It might be true that Needham's experiments yielded 

 results such as he had described, but did they bear out 

 his arguments ? Was it not possible, in the first place, 

 he had not completely excluded the air by his corks 

 and mastic ? And was it not possible, in the second 

 place, that he had not sufficiently heated his infusions and 

 the superjacent air ? Spallanzani joined issue with the 

 English naturalist on both these pleas, and he showed 

 that if, in the first place, the glass vessels in which the 



