OF MALARIA. 17 



stances, healthy places become unhealthy, and sickly 

 places, salubrious. The marsh, the heat, the moisture and 

 the vegetation, remaining apparently the same, the health 

 of a region may vary from one extreme to the other. 



I will now offer you some examples in illustration of 

 these positions: 



McCulloch, the unqualified advocate of the Marsh theo- 

 ry, seems to have been very much perplexed by an excep- 

 tion to his rule, which lay just under his own eye. The 

 canal in St. James' Park, London, was, at the time he 

 wrote, notorious for the abundance of its aquatic plants, 

 causing, in autumn, an even intolerable stench. Yet he 

 congratulates the inhabitants, on their miraculous exemp- 

 tion from malarious fevers, " it being, perhaps, the only 

 exception in the world, at least wherever the climate equals 

 (in temperature) that of England." (p. 50.) 



Let us see how far his assertion is sustainable. The 

 town of Kingston, in the island of St. Vincent, is situated 

 at the bottom of a semicircular bay, and at the foot of a 

 mountain range, with high land on each side. The soil 

 consists of a black alluvial mould, evidently arising from 

 decaying vegetable matter. In one place, the bed of a 

 dried up water-course, branches of trees were found, and 

 the neighboring ground was covered with leaves, in dif- 

 ferent stages of decomposition, for upwards of eight inches 

 in depth, into which the feet sank at every step. " There, 

 then," says the deputy inspector of British hospitals and 

 fleets, Robert Armstrong, "we have all the elements ne- 

 cessary for the production of this vegeto-animal poison, 

 heat, moisture, decayed and decaying vegetable matter, 

 with as large a proportion of reptiles, insects and other 

 animal matters, as is found in other tropical countries ; yet 

 strange to say, the town of Kingston is one of the most 



