^56 VARIETIES IN THE 



tides, capable of being converted into femen, 

 than the former ? It is certain, that the fmall 

 animals eat more, in proportion to their bulk, 

 than the large. But it is likewife probable, that 

 the prodigious increafe of the fmaller animals, 

 as bees, flies, and other infeds, may be owing 

 to the extreme finenefs and delicacy of their or- 

 gans and members, by which they are enabled 

 to feled: the moft fubftantial and mofl organic 

 parts of the animals and vegetables, from which 

 they extra6t their nourifliment. A bee, which 

 lives upon the pureft and moft refined parts of 

 flowers, receives from its food a greater propor- 

 tional quantity of organic particles than a horfe, 

 v^'ho feeds upon hay, ftraw, and the grofler parts 

 of vegetables. The horfe, accordingly, produ- 

 ces but one at a time, while the bee produces 

 many thoufands. The oviparous animals are, 

 in general, fmaller than the viviparous, and they 

 are likewife much more prolific. The long time 

 that the foetus remains in the uterus of vivipa- 

 rous animals, is another obftacle to multiplica- 

 tion : During geftation, and the fuckling of the 

 young, no new generation can take place. But 

 the oviparous animals, w^iich produce, at the 

 fame time, both uterus and foetus, and throw 

 them out of the body, are almoft perpetually In 

 a condition to reproduce ; and it is well known, 

 that, if a hen be prevented from fitting, and be 

 fully fed, the number of her eggs may be great- 

 ly increafed. If hens lay not while they brood, 



it 



