176 MODERN BIOLOGIC THERAPEUSIS 



Africa in prehistoric times. The first historic 

 reference to the disease is an account of an epi- 

 demic which developed in the Abyssinian Army 

 besieging Mecca in the year 571. From Mecca 

 it spread through Asia and Europe. Procopius 

 in his history of the Eastern Empire describes 

 smallpox as present in epidemic form in Con- 

 stantinople in 581, and Gregory of Tours re- 

 cords its presence in Southern France in the 

 same year. 



About the first century, however, there can be 

 little doubt of the presence of the disease and 

 numerous widespread and severe epidemics 

 have been reported. The first accurate descrip- 

 tion is perhaps that of Isaac, but the best of the 

 early descriptions is that of Rhazes who lived 

 in Bagdad about 900. The disease was at first 

 confused with measles, from which it was dis- 

 tinguished by Avicenna; and Sydenham finally 

 gave such a description as to lead to the separa- 

 tion of the two diseases. The disease was prob- 

 ably imported from the Old Country to America 

 early in the sixteenth century, and there were 

 numerous epidemics which exterminated many 

 Indian tribes and reduced others to a handful 

 of individuals. 



