62 Greek Biology 



follow were not without biological writers of very great ability. 

 In the medical school of Alexandria anatomy and physiology 

 became placed on a firm basis from about 300 B.C., but always 

 in the position subordinate to medicine that they have since 

 occupied. Two great names of that school, Herophilus and 

 Erasistratus, we must consider elsewhere. 1 Their works have 

 disappeared and we have the merest fragments of them. 

 In the last pre-Christian and the first two post-Christian 

 centuries, however, there were several writers, portions of 

 whose works have survived and are of great biological impor- 

 tance. Among them we include Crateuas, a botanical writer 

 and illustrator, who greatly developed, if he did not actually 

 introduce, the method of representing plants systematically by 

 illustration rather than by description. This method, important 

 still, was even more important when there was no proper system 

 of botanical nomenclature. Crateuas by his paintings of plants, 

 copies of which have not improbably descended to our time, 

 began a tradition which, fixed about the fifth century, remained 

 almost rigid until the re-discovery of nature in the sixteenth. 

 He was physician to Mithridates VI Eupator (120-63 B.C.), 

 but his work was well known and appreciated at Rome, which 

 became the place of resort for Greek talent. 2 



Celsus, who flourished about 20 B.C., wrote an excellent work 

 on medicine, but gives all too little glimpse of anatomy and 

 physiology. Rufus of Ephesus, however, in the next century 

 practised dissection of apes and other animals. He described 

 the decussation of the optic nerves and the capsule of the 

 crystalline lens, and gave' the first clear description that has 

 survived of the structure of the eye. He regarded the nerves 



1 See the companion chapter on Greek Medicine. 



z The works of Crateuas have recently been printed by M. Wellmann as 

 an appendix to the text of Dioscorides, De re medica, 3 vols., Berlin, 1 906-1 7. 

 The source and fate of his plant drawings are discussed in the same 

 author's Krateuas, Berlin, 1897. 



