INTRODUCTION. 3 



branches of medical science. Experience also taught 

 those ancient physicians that it is always more important, 

 and often easier, to prevent the development of certain 

 diseases, than to arrest their progress when once deve- 

 loped. Consequently physicians turned their attention 

 towards this object. They traced the rules for the 

 preservation of health, and the collection of these rules 

 constitutes a new branch of the art called HYGIENE. 

 As a profession, medicine was first practised primi- 

 by the chiefs of families, of tribes, and of nations 

 anl by generals and legislators. This epoch may be set 

 d..wn as the "PRIMITIVE PERIOD," or that of instinct- 

 ending with the fall of Troy, about twelve centuries' 

 before the Christian era. 



Secondly, It merged into what is called the MYSTIC 



or SA in, |, which extended from the dissolution 



" f U: -an Society " to about the year 500 A.C. 



I'mi.osorinr I'Kuiun, which ended at 



the foundation of the Alexandrian Library, :;L'I A.C. 



Fourthly The ANATOMIC, or Galenic period, which 

 extended to the first age 200th year of the Christian 

 Era. 



lily, The GKKI.K I'KUIOD, which closed at the 

 ruction of the Alexandrian Library, A.I . ii-10. 



' }l] y> T: i:i"i>, which closed with the 



: teenth century. 



Seventhly, The ERUDITE PERIOD, comprising the 

 fiftc teenth century. 



!l] y. -'I; i>, embracing the seven- 



teenth Jiteenth century. 



As a scieiice-so far as regard theories-medicine 

 offers the picture of a great republic, delivered up to 



