140 ON ZOOLOGY. 



according to the climate in which their services 

 are required. In mountainous districts, where 

 pasturage is scanty, we find the goat most fre- 

 quently to supersede the sheep and the cow; and 

 there, from the intricacy and the precipitous 

 state of the roads and passes peculiar to such 

 districts, we observe the prevalence of a larger 

 species of the ass tribe, the progenitor of the 

 mule, whose invaluable services afford to man 

 the facility of traversing countries, which, without 

 them, he could not attempt but at the risk of his 

 life. In certain parts of the world, where land 

 carriage is interrupted by the unevenness of the 

 country, or where from its great extent, long and 

 harassing journies under a vertical sun are 

 requisite to preserve a mutual intercourse with 

 its remoter districts, as in many portions of Asia 

 and Africa, we find the elephant and the camel 

 to prevail ; the former, the largest and most 

 powerful of quadrupeds, the latter, next to the 

 ass, the most docile and the easiest to subsist in 

 situations where, from the scarcity of food and 

 water, all other animals would inevitably perish. 

 In no part of the world that we have made our- 

 selves acquainted with, have been wanting (whe- 

 ther as companions, or as domestic servants of 

 the very first utility,) the dog or the cat ; and 

 though the wild carnivorous animals, many of 

 them so formidable in their aspect and sometimes 

 in their actions, are occasionally destructive to 



