CHOLERA. 505 



took cholera from India, Arabia, Afghanistan, or Persia, through cou- 

 riers and stage-coaches. It soon became clear that cholera, the specific 

 cholera-germ, was in some way or other propagated along the paths 

 of human intercourse, and it also became evident that unless the 

 germs found a suitable soil within a certain time they did not flourish. 

 Observers soon discovered that cholera was more prone to apjjear in 

 certain regions and to affect certain localities, while it shunned other 

 districts ; and, again, that other regions were only visited at intervals 

 of many years. It is also a fact that Asiatic cholera never yet appeared 

 at a place which had not previously been in communication with a 

 region where cholera prevailed ; and, further, that the disease from 

 an infected locality never yet passed on to another place if the jour- 

 ney lasted a certain time without interruption. The large intercourse 

 between India and Europe, more particularly England, by means of 

 ships which sailed round the Cape of Good Hope, had never succeeded 

 in carrying cholera from India to England ; it was only by the over- 

 land route that cholera reached England, Neither had the Cape or 

 Australia ever been visited by cholera. It is possible that in the fu- 

 ture the communication may be so much accelerated that cholera may 

 get to these countries. In much the same way South America escaped 

 during the epidemic (1830-1840) in Europe and North America. It 

 was supposed that in South America yellow fever was enough to pre- 

 vent cholera, or that this disease kept out cholera, until suddenly, in 

 1854, after a service of fast sailing-vessels between Philadelphia and 

 Rio de Janeiro had been established, the chief town in the Brazils ex- 

 perienced a terrible epidemic of cholera. When cholera passes over- 

 land it dies out unless it finds a suitable soil within a certain time. 

 Rainless deserts are unfavorable to cholera. Caravans which pass 

 from infected localities through deserts have never spread the disease, 

 provided the journey in the desert lasted at least twenty days. 



Cholera always requires for its propagation favorable stations on 

 land, and, as a rule, if the course of epidemics be traced, a gradual 

 extension in successive years is found to take place in fixed directions. 

 In the east and southeast of Russia, for example, cholera prevailed 

 after it had raged in Persia in 1868 ; in 1869 eleven, and in 1870 

 thirty-seven provinces were affected, and among them five districts in 

 Poland. In the year 1871 the epidemic spread into the west, east, 

 and north of Russia, and succeeded in reaching East Prussia, when 

 Konigsburg was severely visited, so that from July 24th to November 

 8th, 2,012 individuals died there of cholera ; while in Berlin only 

 fifty-two and in Potsdam only seventy-one succumbed. In 1872 the 

 epidemic reached Eastern Hungary, and in the following years reaped 

 rich harvests in Germany. It has rightly been said, therefore, that 

 cholera does not travel quicker than man. Nevertheless, the spring- 

 like mode of progression of cholera is noteworthy : for example, it 

 regularly jumps from Marseilles to Paris, or vice versa, passing over 



