PRELIMINARY ESSAY ON GENERATION. 
wider circuit; the foramen ovale clofes; the lungs, hitherto inaftive, now firft affume their funftions; the irruption of the 
air diftends them; and this produces the firft fenfation of pain, which the animal exprelies by a ftiriek: fo that the com- 
merscement of our lives, as well as their termination, is marked with pain. 
On a due comparifon of the different modes of generation, we lhall neceffarily draw this conclufion, that the mofl; la- 
boured is the moft perfedt. Of all others, man feems the floweft in coming into life, as he is the floweft in arriving at per- 
fedlion: other animals, of the fame magnitude, feldom remain in the womb above fix months, while he continues nine; 
and, even after his birth, his ftate of imbecility appears prolonged above that of any other. 
We mayalfo obferve, that the generation is the moft compleat by which the feweft animals are produced. Nature, by 
attending to one at a time, feems to exert all her efforts in bringing it to adequate perfeftion-; but, where this attention 
is divided, the animals fo produced come into the world with partial advantages. Thus twins are never, while infants 
at leaft, fo ftrong or fo large as thofe that come fingly into the world; each having in fome meafure deprived the other of 
it'sright; as that fupportwhich Nature intended for one, has been lavifhly divided. 
And as the moft noble animals are produced fingly, fo we find that creatures of this defcription are likewife the leaft 
prolific: thefe ufually produce fingly, and at long intervals; while the more ignoble kinds are more rapid in their returns, 
and more numerous in their births. All the oviparous tribes, and evenibme of the viviparous animals, encreafe in a feem- 
ing proportion to their minutenefs and imperfeftion. Nature appears lavifh of life in the lower orders of creation; and, 
as if fhe intended fuch merely for the ufe of the higher clafTes of animated beings, fhe appears to have beftowed more atten- 
tion in multiplying the number than in compleating the kind. Thus, while the horfe and the elephant produce but one 
at a time, the fpider and the beetle bring forth in thoufands : and even among the fmaller quadrupeds, all the inferior 
kinds are extremely fertile. 
Hence it is evident, that the fmalleft animals multiply in the greateft proportion; and we have abundant reafon for 
gratitude to Providence, that the moft formidable animals are the leaft fruitful. Had the lion and the tiger the fame 
fecundity with the rabbit or the rat, all the arts of man would be ineffedual to oppofe thefe fierce invaders; and they 
would long ere now have become matters of thofe who are themfelves emphatically Itiled the lords of the creation. But 
Heaven has oppofed to man only fuch enemies as he has received ftrength and art to conquer; and as large animals require 
proportional fupplies, it has with-held life where it has not furnifhed the proper means of fubfiftence. 
In confequence of this pre-eftablilhed order, the moil perfeft animals feldom begin to procreate till they have nearly 
acquired their full growth; while the inferior tribes frequently generate before they have arrived at half their natural 
iize. 
In whatever light, therefore, we view this fubjedl, we fhall find room for admiration and thankfulnefs; we lhall be im- 
prefled with a due fenfe of the fuperior advantages conferred on man, both in the mode of his produftion, and in the 
means provided for his future welfare: and while we acknowledge the diftinftions which Providence has beftowed on our 
material part, let us not forget the much more exalted nature of the foul; that endowment which places us infinitely 
above the higheft orders of irrational exiftence, and which gives us a title to immortality! 
I 
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