HISTORY OF MEDICINE. 369 



of each period, that all the several events in the history of phy- 

 sic may be still more easily remembered, by being referred to 

 their proper date., and thereby connected with other events in 

 the history of mankind. With this view, therefore, you will 

 be pleased to observe that the first period of the history of 

 physic extends from the first beginnings of society, perhaps 

 from the creation of the world, to about 400 years before the 

 Christian era, that is about fifty-six years before the birth of 

 Alexander the Great, when Hippocrates, who was the cotem- 

 porary of Democritus, is supposed to have lived. The second 

 period extends from the 400th to the 287th year before Christ, 

 when Ptolemy Philadelphus began to reign in Egypt, under 

 whom Serapion is supposed to have flourished. The third 

 period extends from the time of Ptolemy Philadelphus to the 

 birth of Christ, under the celebrated reign of Augustus Csesar, 

 so well noted for the refined state of literature that then pre- 

 vailed, when Themison flourished. The fourth period extends 

 from the birth of Christ to the middle of the second century 

 after, when Galen flourished, the cotemporary and favoured 

 physician of the Emperor Marcus Aurelius. Thejifth period 

 is a very long one ; it extends from the end of the second to 

 the beginning of the sixteenth century after Christ, when Para- 

 celsus lived cotemporary with the Emperor Charles V., and 

 when the reformation of religion made a very considerable 

 change in the affairs of Europe. The sixth period extends 

 from the time of Paracelsus to the middle of the seventeenth 

 century, about which time the discovery of the circulation of 

 the blood by Harvey came to be very generally understood and 

 received over Europe. This period needs hardly any other 

 mark to distinguish it ; but it was sufficiently remarkable by the 

 civil war that then disturbed Britain, and by the changes that 

 then and immediately after took place in the state of natural 

 knowledge. The seventh and last period extends from the 

 middle of the seventeenth century to the present time, which 

 you are in a condition to distinguish as well as I am, whether 

 you will do it by the age of Frederick II. king of Prussia, or as 

 the period in which the ancient Republic of Poland was arbi- 

 trarily divided among its neighbours. 



One other means of fixing your idea of the history of physic, 



