134 SUPPLEMENTAL HISTORY OF MAN. 



enter fully into the many interesting considerations 

 which this subject involves, we can only point to 

 its more general connexions ; and we do this more 

 with a view to direct that share of attention to it 

 which it deserves, than even to attempt to satisfy 

 our own wishes as to the mode of its consideration. 

 Within the tropics, man is subjected to the almost 

 continual operation of a high temperature, which 

 tends greatly to excite the nervous functions and the 

 vascular activity, notwithstanding the provision with 

 which nature has furnished the integuments which 

 cover his body, in order to moderate the excessive 

 heat to which he is liable. This provision consists 

 chiefly of the dark colour of the rete mucosum, 

 which speedily gives off the superfluous heat of the 

 body, and the great activity of the perspiratory 

 functions, peculiarities which characterize the skin 

 of the races of mankind inhabiting intertropical 

 countries. These countries, and more particularly 

 such of them as are low and swampy, while they 

 abound with the production of the vegetable king- 

 dom, maintain very few of those gregarious animals 

 which serve as articles of food : thus we perceive, 

 that their inhabitants, unless in very elevated and 

 cool situations, as in Abyssinia, Mexico, $*c, are 

 obliged, by the scarcity of those animals, to sub- 

 sist on the vegetable productions of the soil, and to 

 adopt a system of religion which, while it tends to 

 prevent the entire destruction of the more useful 

 species, is sufficient to restrain their numbers within 

 their appropriate means of subsistence, without en- 

 croaching on or impairing those resources with 



