THE CONQUEST OF DISEASE 



The circu- 

 lation of 

 the blood. 



of Aristotle were cast aside, and in their place 

 for a thousand years the : 'Physiologus" and 

 the "Bestiaries," mingling scripture, legends 

 of the saints, and pious inventions, were the 

 authorities: the basilisk killed serpents with 

 its breath; the pelican fed her young with 

 her own blood; certain birds were born from 

 the fruit of certain trees; the cubs of the lion 

 remained three days dead after their birth and 

 then came to life ; animals could be created by 

 a fiat. As late as the seventeenth century it 

 was believed that mice developed out of corn 

 and grains in dark places in the cellar. The 

 lungs were regarded as a bellows for cooling 

 the blood. The blood was supposed to flow 

 and ebb back and forth through the veins. 



Anatomic sources of physiologic information 

 were not reliable. While Vesalius was familiar 

 with the centripetal direction of the blood 

 through the veins, it remained for William 

 Harvey, who had been a pupil of Fabricius 

 (1604), to demonstrate the complete circula- 

 tion of the blood (1616-1619). He published 

 his great discovery in 1628 ("De Motu Cordis 

 et Sanguinis") ; but for ten years or more be- 

 fore that, he had been making dissections and 

 discussing the subject in order to be sure that 



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