OF THE MARSH POISON. 287 



kind, and I shall therefore proceed to draw some conclusions, 

 which I think are fairly warranted from the facts and narrative 

 I have submitted. 



That the marsh poison cannot emanate from vegetable pu- 

 trefaction, I think must be evident from the fact, that it is 

 found most virulent and abundant on the driest surfaces ; of- 

 ten where vegetation never existed, or could exist for the tor- 

 rents, such as the deep and steep ravine of a dried water- 

 course, and that it is^never found in savannahs or plains, that 

 have been flooded in the rainy season, till their surface has 

 been thoroughly exsiccated ; vegetation burnt up; and its pu- 

 trefaction rendered as impossible as the putrefaction of an 

 Egyptian mummy. . If this be doubted or denied, let us take 

 examples where vegetable putrefaction is self-evident, and exa- 

 mine whether it be productive of disease and death, similar to 

 what emanates from the marsh poison. Surely the evidence 

 of every dung heap, in every part of the world, will answer 

 the question in the negative; or if it be insisted that the poi- 

 son is generated from a combination of aqueous and vegetable 

 putrefaction, let us resort to the easy familiar illustration of a 

 West India sugar-ship, where the drain ings of the sugar, mix- 

 ing with the bilge-water of the hold, creates a stench that is 

 absolutely suffocating to those unaccustomed to it ; yet fevers 

 are never known to be generated from such a combination. 

 These are familiar examples ; but I cannot think they should 

 be of less intrinsic value on that account, or be deemed less 

 conclusive. The Italians, to be sure, have published ordonan- 

 ces against the steeping of hemp in stagnant pools, but these 

 resemble many other ordonances relative to health everywhere ; 

 in overlooking the leading primary causes of the stagnant 

 pool, the autumnal season, and the malarious lands around, 

 vol. ix. p. ii. o o and 



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