NATirilAL THEOLOGY. 117 



in succession as the residence of man ; and, in his 

 absence, entertain other guests, which, by their 

 sudden multiphcation, fill the chasm. In domesti- 

 cated animals, we find the effect of their fecundity 

 to be, that we can always command numbers ; we 

 can always have as many of any particular species 

 as we please, or as we can support. Nor do we 

 complain of its excess; it being much more easy 

 to regulate abundance, than to supply scarcity. 



But then this superfecundity, though of great 

 occasional use and importance, exceeds the ordi- 

 nary capacity of nature to receive or support its 

 progeny. All superabundance supposes destruc- 

 tion, or must destroy itself. Perhaps there is no 

 species of terrestrial animals whatever, which 

 would not overrun the earth, if it were permitted 

 to multiply in perfect safety ; or of fish, which 

 would not fill the ocean: at least, if any single 

 species were left to their natural increase without 

 disturbance or restramt, the food of other species 

 would be exhausted by their maintenance. It is 

 necessary, therefore, that the effects of such pro- 

 lific faculties be curtailed. In conjunction with 

 other checks and limits, all subservient to the 

 same purpose, are the thinnings which take place 

 among animals, by their action upon one another. 

 In some instances we ourselves experience, very 

 directly, the use of these hostilities. One species 

 of insects rids us of another species; or reduces 

 their ranks. A third species, perhaps, keeps the 

 second within bounds ; and birds or lizards are a 



