26 SCIENCE OF THE GREEKS. PT. I. 



CHAPTER IV. 



280 TO 120 B.C. 



Erasistratus and Herophilus Eratosthenes Hipparchus Precession 

 of the Equinoxes. 



Erasistratus and Herophilus. At the time when Archi- 

 medes was studying in Alexandria, two physicians were 

 teaching there, who are famous in the history of anatomy, 

 or the structure of the body. The one was Erasistratus 

 and the other Herophilus. The birthplaces and dates of 

 these two physicians are doubtful, but we know that they 

 were the first men who dissected the human body, and gave 

 a clear account of its parts. Erasistratus, in particular, 

 described the brain and its curious windings or convolutions, 

 and the division between the cerebrum or front part and 

 the cerebellum or hinder and lower part. He seems also 

 to have known that it is by means of our brain that we feel 

 everything, and that it is the nerves which carry messages 

 from different parts of our body to our brain. Herophilus 

 traced out the tendons or strong cords which fasten the 

 muscles to the bones ; the ligaments or fibrous cords which 

 unite one bone to another ; and the nerves. He was the 

 first physician who pointed out that in feeling a pulse you 

 must notice three things : ist, how strongly it throbs ; 2d, 

 Low quickly ; 3d, whether the beats are regular or irregular. 

 Many of the names which Erasistratus and Herophilus gave 



