Chapter XVII 



The Motion and Circulation of the Blood is 



Established by What is Displayed in 



the Heart and Elsewhere by 



Anatomical Investigation 



»>-•-« 



I 



DO not find the heart a separate and distinct 

 organ in all animals. Some, called plant-animals, 

 have no heart at all. These animals are colder, have 

 little bulk, are softer, and of uniform structure, 

 such as grubs, worms, and many which come from 

 decayed material and do not preserve their species.^ 

 These need no heart to impel nourishment to their 

 extremities, for their bodies are uniform and they 

 have no separate members. By the contraction and 

 relaxation of the whole body they take up and move, 

 expel and remove aliment. Oysters, mussels, sponges 



^ Harvey really says "generated from decayed material." This 

 idea of spontaneous generation, current from the beginning of philoso- 

 phical speculation, received its first serious blow from Francesco 

 Redi ( 1 626-1 694) in his Experientia circa generationem insectorum, 

 Amsterdam, 1671. The final blow, covering microscopic forms of 

 life, was given by L. Pasteur (1822-1895). In his De generatione 

 animalium, 1651, Harvey maintained the theory that the organism 

 is not preformed in the ovum, but that it gradually evolves by growth 

 and union of its parts. This, as Garrison says, "subverted the ancient 

 concept that life is engendered out of corruption (or putrefaction)." 



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