SWAMPY COAST LINES. 63 



This, however, is a matter to which we shall refer 

 more at length hereafter. 



The flat character which the land is known to assume 

 upon the seaboard of many countries, accounts for the 

 formation of extensive areas of swampy land in such 

 localities. Now it may be accepted as a matter of 

 ascertained fact, that wherever stagnant water is 

 associated with a powerful sun, malarial diseases are 

 always prevalent and therefore as a rule we find the 

 coast line of most tropical countries is unhealthy; and 

 in many cases it may even be considered deadly to 

 Europeans, at certain seasons. 



But as we penetrate into the interior and ascend the 

 highlands, the climate in general becomes compara- 

 tively healthy. We shall here confine our remarks to 

 the case of tropical countries, as the climates of temperate 

 regions call for no particular notice in this respect: 

 notwithstanding the great mortality, already referred 

 to, in the Walcheren Expedition, where a number of 

 circumstances point to the conclusion that the malarial 

 affections were more or less complicated by those 

 of a typhoid character, probably due, not to solely 

 climatic influences, but to a contamination of the water 

 supply. 



The land upon the seaboard, as we have pointed out, 

 often rises very gradually from the coast, and therefore 

 in tropical regions a wide belt of unhealthy country, 

 generally clothed with dense forests, has to be traversed 

 before the highlands can be reached. The coasts of the 

 African continent, especially those of the west coast, 

 largely partake of this character. This has constituted 

 one of the difficulties of African travel, which has contri- 

 buted probably more than anything else to establish 



