On Malaria. 317 



for wood and water ; but when it is unavoidable, the natives of such 

 countries should be procured to perform the labor, and all communi- 

 cation with the shore in boats should be in the day time, at full wa- 

 ter ; as on the banks of rivers, or on the sea shore, at low water, the 

 exhalations from the mud are of the most pestilential character. No 

 man should go on shore after sun-set when in harbor, nor before 

 breakfast, nor be on the decks at all in the night, and the watch should 

 be limited to the smallest possible number of men, to whom " smoking 

 constantly while in the open air," should be recommended. Whenever 

 any part of a crew are necessitated to engage in the dangerous em- 

 ployment of wooding and watering, fires lighted at short distances 

 would be of great value, and " ought to be a standing order during 

 such service." No boat should, by any means, be out after sun-set. 



The consequences of inundation after the waters retire, are seen 

 in every climate, producing diseases, differing in the degrees of sever- 

 ity, from the mild tertian agues of cool climates, occasioned by a low 

 meadow or a mill pond ; to the sudden and terrific fevers on the del- 

 tas of the Nile and Oronoco, and other rivers of the tropics. In 

 these regions the heat is continual for long periods ; the effects are 

 sometimes instant, and the mortality frightful. 



It is on the rice plantations of our southern States, in Mobile, 

 New Orleans, and the countries which form the deltas of the Missis- 

 sippi and its tributaries, that malaria has raised its throne on this con- 

 tinent ; and were it not for the mysterious ability of the negro to re- 

 sist the influences which destroy the white or Caucasian race of 

 men, those vast alluvial regions would, of necessity, be resigned to 

 tlieir original denizens. It is a question interesting to naturalists, 

 whether this capability of resisting the effects of malaria resides in 

 the texture of the negro's skin, or in some more latent peculiarity of 

 structure or functions ; and it is important to medical science, to as- 

 certain whether it is resisted by the pores of the external and internal 

 surfaces, or by respiration, as we may hence discover some clue to 

 the mode of its attack. 



I will detain you with but one other cairse of malaria, which I am 

 bound not to omit, as it is one of extreme danger, from its following 

 closely upon a very extensively prevailing human propensity — and 

 that is, neglect. 



Were it not that I might injure the value of real estates in some parts 

 of this country, I could point out by name several excellent farms, 



