386 HISTORY OF 



duction of one at a time, seems to exert all her 

 efforts in bringing it to perfection ; but where 

 this attention is divided, the animals so produced 

 come into the world with partial advantages. In 

 this manner twins are never, at least while in- 

 fants, so large or so strong as those that come 

 singly into the world j each having, in some 

 measure, robbed the other of its right ; as that 

 support, which nature meant for one, has been 

 prodigally divided. 



In this manner, as those animals are the best 

 that are produced singly, so we find that the 

 noblest animals are ever the least fruitful. These 

 are seen usually to bring forth but one at a time, 

 and to place all their attention upon that alone. 

 On the other hand, all the oviparous kinds pro- 

 duce in amazing plenty ; and even the lower 

 tribes of viviparous animals increase in a seeming 

 proportion to their minuteness and imperfection. 

 Nature seems lavish of life in the lower orders of 

 the creation ; and as if she meant them entirely 

 for the use of the nobler races, she appears to 

 have bestowed greater .pains in multiplying the 

 number than in completing the kind. In this 

 manner, while the elephant and the horse bring 

 forth but one at a time, the spider and the beetle 

 are seen to produce a thousand ; and even among 

 the smaller quadrupeds, all the inferior kinds are 

 extremely fertile ; any one of these being found, 

 in a very few months, to become the parent of a 

 numerous progeny. 



In this manner, therefore, the smallest animals 

 multiply in the greatest proportion j and we have 



