On Malaria^ 49 



appear, though those particular winds are so charged with fog, 

 as to darken the whole country for days : and it will be found 

 an invariable rule all over the world, that when a fog is the 

 apparent cause of disease, or when an east wind is such, it is 

 because these have been generated in a land of marshes, or 

 have traversed one ; and that, under other circumstances, or 

 where no pernicious land lies in the way, they are as innocent 

 as any other fogs and winds, and that the hazard and the suf- 

 fering will arise from those, be they whatever they may, which 

 traverse pestilential lands. 



But I must defer this particular and interesting subject to 

 another occasion, lest I make this article too long ; and proceed 

 to examine some other circumstances connected with the 

 transportation of malaria. 



First, however, I must notice one fact as to this transporta- 

 tion from Holland, partly because it is a necessary fact in the 

 history of malaria, and partly because it might be used as an 

 argument against the view which I have just given. The east 

 winds of autumn are not supposed to bring remittents, as those 

 of spring bring agues, though I cannot assert that this is abso- 

 lutely true. Being assumed, the solution is easy. If the winds 

 of this nature in spring are notedly moist, and thus vehicles of 

 malaria, the case is exactly the reverse with the east winds of 

 summer and autumn ; or as the east wind may be the most 

 moist of winds, so may it be the most dry ; while it is a conse^ 

 quence of its extreme dryness, in fact, that it is always the 

 very cause of our burning summers. This is the history of our 

 last summers, and it is invariable, whether as it relates to sea- 

 sons or single days ; and it is plainly owing to its permitting 

 the more ready transmission of the sun's rays. That it is the 

 very harmattan of Africa, it is almost unnecessary to say ; and 

 as dry wind is not a conductor of malaria, as that poison is in 

 fact decomposed or destroyed in these circumstances, daily and 

 invariably, it is easy to see why the remittents of Holland 

 should not be transported, like its intermittents, though even 

 this may possibly happen under particular circumstances. 



To proceed; and to the next remarkable facts connected 

 with the propagation of malaria. — The most singular of these is 

 its limitation, or that yet unexplained property by which it is 



JULY— OCT. 1827. E 



