I GREEK BIOLOGY AND MEDICINE 



v 



Belonging to Harvey's own generation, the 

 extraordinary Fleming, van Helmont, forms a 

 link between Paracelsus and the theorizing 

 systems of the medico-chemical and medico- 

 physical schools of the early seventeenth cen- 

 tury. The chemical school (Sylvius of Leyden 

 may be called the founder) starts from the con- 

 ception of fermentation through the action, for 

 example, of the saliva and gastric juices upon 

 foods. Health consisted in the proper balance 

 of acids and alkalies, and sickness in the excess 

 of one or the other. The cure lay in the re- 

 duction of the excessive element. On the 

 other hand, the physicists, starting from the 

 admitted circulation of the blood, sought a 

 physical or mechanical interpretation of all 

 bodily processes. Health lay in their unim- 

 peded action. 



Since the physical as well as chemical knowl- 

 edge of that time was utterly inadequate for 

 the basis of sound medical practice, a reaction 

 was to be expected. The advocates of these 

 theories had drawn more than one conception 

 from Greek medicine, to weave into their 

 systems. Now the reaction inaugurated by 

 the Englishman, Thomas Sydenham (1624- 

 1689), directed itself toward the conscious 



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