108 CHOLERA. 



miles a day, whilst at another, it flies on the wings of 

 commerce, almost as fast as there are means of convey- 

 ance for men and merchandize. At one time, it ascends 

 or descends along the valley of an innavigable stream, 

 slowly and regularly, as if progressive by its own loco- 

 motion ; at another, it flies with the ship or the loco- 

 motive, across seas and continents. A stranded vessel 

 throws it upon the shore of a lonely sea-island, (Dick- 

 son.) One ship conveys it from Dublin to the St. Law- 

 rence,* another meets it in the midst of the Atlantic ', and 

 carries it to New York,f while a third, from the same 

 source,J deposits it at New Orleans. Steamers scatter it 

 far and wide as they ascend from New Orleans to the 

 various branches of the river above. Contagion might ex- 

 plain the progress, where there are always materials to 

 form a line of march, but contagion cannot account for 

 its solitary advance over untravelled wastes or untenanted 

 seas. Contagion cannot explain its presence in the atmo- 

 sphere of the mid-ocean, nor its manner of assailing a city 

 at once, at its most opposite points. Contagion is at fault 

 as explanatory of the exemption of classes, the almost ex- 

 clusive invasion of low, damp, dirty habitations, and the 

 uniform appearance of a general premonitory state, be- 

 fore the irruption of the cholera itself. 



The attacks of cholera within a few hours after expo- 

 sure to infection, the introduction into hospitals of large 



* The Carricks. f The packet ship New York. 



J The ship S wanton, Captain Duncan, from the healthy port of Havre, 

 was assailed by cholera after being at sea for twenty-eight days, (Lat. 25 N., 

 Long. 57 W.,) and after losing fifteen persons in thirteen days, she arrived 

 in the Mississippi, five days before the epidemic outbreak at New Orleans. 



The Ship New York, also from Havre, was attacked at sea, sixteen days 

 out, and arrived at Staten Island, two days before the cholera appeared at 

 the New York Quarantine Station. (Whiting.) 



