HIS WORKS. .bdii 



In the often-quoted passage from the work ( De Plantis/ 1 it is 

 still the spirit inherent in, or associated with, the blood, that 

 is the cause of its motion. 



Csesalpinus, consequently, tried by a very moderately 

 searching criticism, presents himself to us as but very little 

 farther advanced than the ancients in his ideas on the motion 

 of the blood. The interpretation which successive generations 

 of men give to a passage in a writer, some century or two old, 

 is very apt to be in consonance with the state of knowledge at 

 the time, in harmony with the prevailing ideas of the day, 

 and, doubtless, often differs signally from the meaning that 

 was in the mind of the man who composed it. The world 

 saw nothing of the circulation of the blood in Servetus, 

 Columbus, Csesalpinus, or Shakespeare, until after William 

 Harvey had taught and written. 



The truth is, that some of the foremost grounds of 

 Harvey's claims to rank as a discoverer are very commonly 

 overlooked. We always associate his name and fame with the 

 development of the ultimate fact of the circulation of the blood. 

 But Harvey, as a step to this conclusion, first demonstrated 

 the heart as the means by which the circulation was effected; 

 and he farther showed that there was but one kind of blood, 

 common to both the arteries and the veins. Up to his 

 time the heart was regarded as the passive cistern of the blood, 

 and the elaboratory of the vital spirits; it was not known 

 as the moving instrument in any efflux or reflux of the blood, or 

 even of any lesser circulation that had been previously asserted 

 or conjectured. The moving power was still the respiratory act. 

 Harvey may be said to have first broached, as he also essen- 

 tially completed the physiology of the heart's actions. The 

 circular motion of the blood followed as a necessary corollary 

 from these. The " motion of the heart" has even prece- 

 dence in the title of his immortal work ; the chapter in which 



1 Qua autem ratione fiat aliment! attractio, &c. De Plantis, lib. i, cap. 2, p. 3, 

 4to, Florent. 1583. 



