Iri JV'otes to Introductory Lecture, 



Hippocrates also speaks of the <* vessels communicating 

 with each other, and of the hlood undergoin.^ a kind of flux 

 and reflux from and to the heart like the ehhing and flowing 

 of the sea," and even mentions the throhhing of the temporal 

 arteries, as an evidence of the fact. Galen also had (as I 

 have before said,) showed that the arteries contained blood 

 as Avell as the veins, bj the simple experiment of dividing a 

 branch between two ligatures in a living subject, and thus 

 disproved the opinion of the Alexandria school, that they 

 merely contained air. The lesser circulation, or that through 

 the lungs, had been ascertained by Servetus a Spanish phy- 

 sician, and by Columbus the pupil of Vesalius, and was known 

 to other eminent men; and Cossalpinus an Italian even men- 

 tions the communication between the arteries and veins at 

 ^heir extremities, and speaks of the valves of the arteries 

 and auricles as capable of preventing the return of the blood, 

 but still it is apparent from other parts of his writings that 

 he had no consistent idea of their use or of the circulation. 

 Further, the early discovery of the valves of the heart, and 

 those placed at the mouths of the large arteries which had 

 been made by Erasistratus ; of those in the veins of the ex- 

 tremities by Sylvius, as mentioned by Stephanus, and the dis- 

 covery of similar valves in the veins of the arm by Fabricius 

 of Padua, the preceptor of Harvey, it would seem might 

 at once have led to the belief of the existence of a similar 

 organization in the veins of other parts of the body, and to a 

 knowledge of their use in preventing the return of the blood, 

 to the extremities, and to the deduction of its having been 

 previously carried from the heart by the arteries. It was 

 this organization of the veins that furnished Harvey with one 

 of the strongest arguments in favour of his sublime dis- 

 covery. Finally, says Dr. Hunter, " the obvious phsenomena 

 in bleeding animals to death, the different eff*ects of ligatures 

 on diff*ereut vessels, the practice of surgery with regard to 

 bleeding and blood vessels, the action of the heart when ex- 

 posed to view in living bodies, ail these so evidently proclaim 



