6 SCIENCE OF THE GREEK'S. PT. i. 



CHAPTER IV. 



280 TO 120 B.C. 



Erasistratus and Herophilus study the Human Body Eratosthenes the 

 Geographer lays down the First Parallel of Latitude, and the First 

 Meridian of Longitude He measures the Circumference of the 

 Earth Hipparchus writes on Astronomy Catalogues 1,080 Stars 

 Calculates when Eclipses will take place Discovers the Pre- 

 cession 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 cere- 

 bellum or hinder and lower part. He seems also to have 

 known that it is in 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 is the first physician who 

 pointed out that in feeling a pulse you must notice three 



