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tive and incorruptible p'arts common to animals and to vegetables. 

 These organic molecules cast themselves into the moulds or 

 shapes which constituted different beings. When one of those 

 moulds was destroyed by death, the organic molecules became 

 free ; ever active, they worked the putrefied matter, appropriat- 

 ing to themselves some raw particles and forming, said 

 Buff on , "by their reunion , a multitude of little organized 

 bodies, of which some, like earthworms, and fungi, seem to 

 be fair-sized animals or vegetables, but of which others, in 

 almost infinite numbers, can only be seen through the 

 microscope." 



All those bodies, according to him, only existed through 

 spontaneous generation. Spontaneous generation takes place 

 continually and universally after death and sometimes during 

 life. Such was in his view the origin of intestinal worms. 

 And, carrying his investigations further, he added, " The eels 

 in flour paste, those of vinegar, all those so-called microscopic 

 animals, are but different shapes taken spontaneously, accord- 

 ing to circumstances, by that ever active matter which only 

 tends to organization." 



The Abbe Spallanzani, armed with a microscope, studied 

 these infinitesimal beings. He tried to distinguish them and 

 their mode of life. Needham had affirmed that by enclosing 

 putrescible matter in vases and by placing those vases on warm 

 ashes, he produced animalculae. Spallanzani suspected : 

 firstly that Needham had not exposed the vases to a sufficient 

 degree of heat to kill the seeds which were inside ; and secondly, 

 that seeds could easily have entered those vases and given 

 birth to animalculae, for Needham had only closed his vases 

 with cork stoppers, which are very porous. 



"I repeated that experiment with more accuracy," wrote 

 Spallanzani. " I used hermetically sealed vases. I kept them 

 for an hour in boiling water, and after having opened them 

 and examined their contents within a reasonable time I found 

 not the slightest trace of animalculse, though I had examined 

 with the microscope the infusions from nineteen different 

 vases." 



Thus dropped to the ground, in Spallanzani's eyes, Need- 

 ham's singular theory, this famous vegetative force, this occult 

 virtue. Yet Needham did not own himself beaten. He 

 retorted that Spallanzani had much weakened, perhaps de- 

 stroyed, the vegetative force of the infused substances by 



