INTRODUCTION. 17 



constantly, or at certain seasons of the year, we find 

 the animals undergo another change, they are calcu- 

 lated for leaping or wading, as is the case with the 

 ostrich on the borders of the great African desert, and 

 the emu and the kangaroo in New Holland. 



This adaptation is not confined to any one race, or 

 to any one instinct of the race : it applies to them all, 

 and to all their habits. Some of them are not a little 

 singular. On the continuous plains, whether these be 

 adapted for occasional or for constant residence, the 

 young animals are left to use their own legs from the 

 time of their birth ; but when the country consists of 

 patches, and there must be, as it were, daily marches, 

 the mother is provided with a marsupium, or pouch, 

 in which she can carry her young until they have ac- 

 quired size and strength adapted to the nature of the 

 ground upon which they are to find their food. This 

 is the case with the kangaroo," and indeed with most 

 of the quadrupeds of Australia, with all of them that 

 can be considered as native, peculiar to that country, 

 and as singular as it is in its geography. 



Where there is herbage, whether permanent or sea- 

 sonal, we find animals that browse herbage ; where 

 there are many native fruits, we find animals that can 

 live upon trees ; and where there is a tendency in hard 

 and prickly plants to overrun the ground, we find 

 elephants, and other animals that consume these. Thus 

 every vegetable-consuming animal, by consuming one 

 kind of vegetable, gives scope for other kinds ; and thus 

 yields food for other animals. Each has its destroyer ; 

 each has also that which it fattens ; and these are 

 so balanced, that the whole conduce to good. While 

 c 3 



