1885.] on Cliolera : its Cause and Prevention. 291 



1819 the channels of EurojDean commerce in the East were more 

 thoroughly contaminated than they had ever been before. Modern 

 experience teaches us that though cholera is very unapt to spread 

 in this way, it may do so ; and I confess it appears to me quite 

 impossible to doubt that in those early years of its history it did so. 



From 1820 onwards we have evidence that cholera has never been 

 absent from Bengal, and has behaved throughout in the same way 

 that it does now. The best general idea of the extent of its influence 

 and of the differences which subsist between years of great epidemic 

 prevalence and others, may be gained by an examination of the series 

 of maps which have been published by the Indian Government. The 

 conclusions which these maps suggest, and which are confirmed by 

 the more minute and exhaustive study of cholera statistics which 

 has been made by Dr. Bryden,* may be summarily stated as 

 foUov/s. 



Within certain areas, the limits of which comprise the alluvial 

 plains adjoining great rivers, and particularly in the deltas of such 

 rivers, cholera is always present. Outside these so-called endemic 

 areas some places are distinguished by their liability to the epidemic 

 prevalence of the disease, others by their special immunity, and in 

 general no relation can be traced between liability to epidemic pre- 

 valence and personal intercourse with infected districts; so that, 

 however clear it may be that the infection of cholera is capable, 

 under certain conditions, of being conveyed from place to place, 

 Indian experience affords no ground for attributing any importance 

 to such conveyance as a means of the spread of cholera in that 

 country. 



Let me now try to give an account of the circumstances which led 

 to the escape of cholera, if such an expression may be used, from its 

 Indian home into Europe. As probably every reader knows, the first 

 European country invaded by cholera was Russia, and the first 

 European town of any importance was Orenburg, on the Ural, one of 

 the great feeders of the CasjDian. How did cholera find its way from 

 the Indian Peninsula to the Caspian ? The only answer that can be 

 given is that the communication took place by way of Persia, and that 

 Persia itself was invaded not, as has been sometimes said, by Afghan- 

 istan, but by the Persian Gulf. In 1821 — that is, a year after the 

 epidemic of Zanzibar — there was a destructive outbreak of cholera at 

 Muscat in Arabia and at the Persian port of Bushire, and a little 

 later at Bagdad. From these littoral beginnings the epidemic spread 

 during the next year (1822) over the whole of Persia and great part 

 of Asia Minor. In 1823 it was in Damascus and Aleppo, having at 

 the same time or previously existed in Iskanderoon and other places 

 on the Mediterranean. It is usually stated that in 1822 cholera 



* See ' Epidemic Cholera in the Bengal Presidency.' By James L. Bryden, 

 M.D. Calcutta. 1869. 



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