THE MICKOBES OF HUMAN DISEASES. 195 



The presence of the bacillus of typhoid fever in 

 the air or in water has not yet been ascertained. 

 Neither is anything known about the microbe which 

 may be assumed to be the cause of typhus fever. 



VIII. THE CHOLERA MICROBE. 



This terrible disease has its origin in Asia, where 

 its ravages are as great as those of yellow fever in 

 America. It is endemic or permanent in the Ganges 

 delta, whence it generally spreads every year over 

 India. It was not known in Europe until the begin- 

 ning of the century ; but since that time we have had 

 six successive visitations, and it seems destined to 

 replace the plague or black death of the Middle Ages, 

 a disease which appears to be now confined to some 

 few localities of the East.* 



In 1817, there was a violent outbreak of cholera 

 at Jessore, India. Thence it spread to the Malay 

 Islands, and to Bourbon (1819) ; to China and Persia 

 (1821); to Russia in Europe, and especially to 

 St. Petersburg and Moscow (1830). In the following 

 year it overran Poland, Germany, and England, and 

 first appeared in Paris on January 6, 1832; here it 

 raged until the end of September. 



* See in the Annuaire de ih&rapeutique, 1885, Bouchardat's 

 account of cholera epidemics in Paris, together with remarks on the 

 nature, the parasite, the hygiene, and the treatment of cholera. 



