240 ANDREW JACKSON HOWE. 



tions, distinct in point of place, but not of time ; " for 

 the two auricles move together, and so also do the 

 two ventricles, in such wise that though the places be 

 four, the times are only two." The expiring beats of 

 the heart were observed by Harvey in many ways, he 

 thoroughly understanding that the living heart of 

 fishes and reptiles will beat for hours after being re- 

 moved from the body, and that different parts of the 

 organ will throb after being cut in pieces that is, he 

 had observed the fact, though he might not have un- 

 derstood the origin of the nerve force which im- 

 pressed the muscular structure of the organ. 



Harvey's knowledge of the fetal circulation was 

 correct. He says : 



"In embryos, whilst the lungs are yet in a state of inaction, 

 performing no function, subject to no motion, any more than if 

 they had not been present, nature uses the two ventricles of the 

 heart as if they formed but one, for the transmission of the blood. 

 The condition of the embryos of those animals which have lungs, 

 whilst those organs are yet in abeyance and not employed, is the 

 same as that of those animals which have no lungs." 



A curious remark of Harvey in regard to the 

 pulmonary circulation, is accidentally true. He says : 

 " The blood is sent through the lungs that it may be 

 tempered by the air that is inspired, and prevented 

 from boiling up, or something else of the sort." Now 

 it happens to be a fact demonstrated of late years, 

 that the blood is actually cooled by coming into the 

 lungs. Aeration of the blood is a heating process, 

 yet inspired air exercises a cooling effect in the lungs. 

 This is about the only instance in which Harvey 

 stumbled upon a correct conclusion. 



It has been asserted over and over again that 

 Harvey never knew any thing about the capillaries, 



