GIO NATUilAI THEOLOaY 



use and importance, exceeds the ordinary capacity of uatUT<' 

 to receive or support its progeny. All superabundance sup- 

 poses destruction, 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 per- 

 fect 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 restraint, the food of other species 

 would be exhausted by their maintenance. It is necessary, 

 therefore, that the effects of such prolific faculties be cur- 

 tailed. In conjunction with other checks and limits, all 

 subservient to the same purpose, are the thiiuiings 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 insect rids us of 

 another species, or reduces their ranks. A third species, 

 perhaps, keeps the second within bounds ; and birds or liz- 

 ards are a fence against the inordinate increase by which even 

 these last might infest us. In other, more numerous, and 

 possibly more important instances, this disposition of things, 

 although less necessary or useful to us, and of course less 

 observed by us, may be necessary and useful to certain other 

 species ; or even for the preventing of the loss of certain 

 species from the universe — a misfortune wliich seems to be 

 studiously guarded against. Though there may be the ap- 

 pearance of failure in some of the details of nature's works, 

 in her great purposes there never are. Her species never 

 fail. The provision which was originally made for continu- 

 ing the replenishment of the world, has proved itself to be 

 effectual through a long succession of ages. 



What further shows that the system of destruction 

 among annuals holds an express relation to the system ol 

 fecundity, that they are parts indeed of one compensatory 

 scheme, is, that in each species the fecundity bears a pro- 

 portion to the smallness of the animal, to the weakness, to 

 the shortness of its natural term of life, and to thfi dangers 



