Procccdi.igs of the Ohio State Academy of Science 453 



Harvey's discovery. "And now for the lirst time was clear 

 the puijiose of those valves in the veins, whose structure and 

 position had been demonstrated to Harvey, by the very hands 

 of their discoverer, his old master, Fabricius, who did not 

 rightly understand their use, and concerning which succeed- 

 ing anatomists have not added anything to our knowledge." 



Harvey speaks of the spirits but casts it aside as not es- 

 sential to his work. However, his discovery killed the idea of 

 the natural spirits being carried by the veins and the vital 

 spirits being carried by the arteries. He considers the blood 

 the same blood all the time going in a circle meeting with 

 change in the lungs and in the tissues of the body as it goes. 

 His discovery leads easil}^ to the understanding of the chemi- 

 cal phenomena going on in the body and the relation of the 

 blood circulation to the nutrition in the body and the produc- 

 tion of power for the body to carry on the processes neces- 

 sary to its life. The fact that the food disappears from the 

 alimentary canal and in some way becomes blood v/as known 

 from the time men began to think of the activities m their 

 own bodies, but how this was done was left to Harvey's time. 



Gasper Aselli discovered the lacteals in 1622 in a way 

 that some might think an accident. In working on the viscera 

 of a dog he noticed some fine white cords in the mesentery 

 taking them to be nerves at first, "but presently I saw that I 

 was mistaken in this since I noticed that the nerves belonging 

 to the intestine were distinct from these cords, and wholly 

 unlike them. But presently recovering from his surprise he 

 pricked one of the larger cords with a sharp scalpel and im- 

 mediately a milky substance came forth. Afterwards he dem- 

 onstrated this to many learned men and they were all "very 

 much struck with the novelty of the thing." AselH noticed 

 valves in the lacteals and saw that they hindered the flow of 

 the chyle, but doubtless influenced by the belief of the times 

 tliat all of the food had to go to the liver for elaboration he 

 supposed that these lacteals ended in the liver; in fact he said 

 that he could trace them to the liver. It was left for Pecquet. 



