6 



THE BLOOD 



some measure, lest it should run pell-mell into the 

 feet, hands, and fingers, there to be impacted " : 

 they were to prevent distension of the veins, and 

 to ensure the due nourishment of all parts of the 

 body. It is true that he compared them to the 

 locks or weirs of a river, but he understood neither 

 the course nor the force of the blood : as Harvey 

 said of him, " The man who discovered these valves 

 did not understand their right use ; neither did 

 they who came after him " — Harum valvularum 

 usum rectum inventor non est assecutus, nec alii 

 acididerunt ; non est enim ne pondere deorsum 

 sanguis in inferior a totus mat ; stmt namque in 

 jugularibus deorsum spectantes, et sanguinem sur- 

 sum ferri prohibentes. Men had no idea of the 

 rapidity and volume of the circulation ; they 

 thought of a sort of Stygian tide, oozing this way 

 or that way in the vessels — Csesalpinus was of 

 opinion that it went one way in the daytime and 

 another at night — nor did they see that the pul- 

 monary circulation and the general circulation are 

 one system, the same blood covering the whole 

 course. The work that they did in anatomy was 

 magnificent ; Vesalius, and the other great anato- 

 mists of his time, are unsurpassed. But physiology 

 had been hindered for ages by fantastic imaginings, 

 and the facts of the circulation of the blood were 

 almost as far from their interpretation in the six- 

 teenth century as they had been in the time of 

 Galen. 



