Proceedings of the Ohio State Academy of Science 447 



made the veins hollow for the sake of their function that like 

 streams they might pervade the hody." Although he makes 

 great claims for his discovery he failed to appreciate the im- 

 portance of it, as many did after his time. 



xAndreas Caesalpinus differed greatly from Columhus. 

 Columbus lacked culture. His education was comparatively 

 limited. Vesalius refers to him as the smatterer. The exact 

 reverse of this was Caesalpinus. He was versed in all of the 

 knowledge of his time. Born in 1519; we find him professor 

 of medicine at Pisa from 1567 to 1592. He was an ardent fol- 

 lower of Aristotle's philosophy. He was a naturalist, for we 

 find him teaching botany as well as medicine at Pisa. Being- 

 more of a philosopher than a naturalist he was inclined to 

 dispute everything. He went so far as to not only dispute all 

 that Galen said but to hold that all that Galen opposed was 

 correct. He understood the working of the valves of the 

 heart. "For the membranes are so placed at the orifices that 

 tliey are opened when the heart is dilated and are closed when 

 the heart is contracted." He still holds to the idea of the 

 spirits and the two kinds of blood. He associated the pulse 

 in the arteries with the beat of the heart and explained the 

 working of the heart correctly in receiving and discharging 

 tlie blood. He notices that the arteries expand when tlie 

 heart contracts and that the valves are so placed that the blood 

 can not get back from the arteries when the heart relaxes. 

 "If therefore the arteries were dilated and constricted at the 

 same time as the heart, it would follow that they would be 

 dilated at the time when the material filling them from the 

 heart was denied them, and constricted at a time when ma- 

 terial was flowing into them from it. But it is manifest that 

 this is impossible." He is the first to grasp the idea that the 

 blood is discharged from the heart into the arteries and that 

 the heart receives the blood from the veins, not only from the 

 ]:)ulmonary vein but also from the venae cavae. He seems to 

 eet the idea of a connection of the arteries Avith the veins in 



