222 THE PHILOSOPHY 



polifhing a barbarous people. Thus, the moft fubftantial good of- 

 ten proceeds from apparent misfortune. 



There is hardly a plant that is not rejeded as food by fome ani- 

 mals, and ardently defired by others. The horfe yields the common 

 water-hemlock to the goat, and the cow the long-leafed water-hem- 

 lock to the fheep. The goat, again, leaves the aconite, or bane-ber- 

 ries, to the horfe, &c. Plants which afford proper nourifliment to 

 fome animals, are by others avoided, becaufe they would not only 

 be hurtful, but even poifonows. Hence no plant is abfolutely dele- 

 terious to animal life. Poifon is only a relative term. The euphor- 

 bia, or fpurge, fo noxious to man, is greedily devoured by fome of 

 the infedl tribes. 



It is a maxim univerfally received, that every animal, after birth, 

 grows, or acquires an augmentation of fize. The fpider-fly, how- 

 ever, affords an exception. The mother lays an egg fo dlfpropor- 

 tionally large, that no perfon, without the aid of experience, could 

 believe it to have been produced by this infed. When the egg is 

 hatched, a fly proceeds from it, which, at the moment of birth, 

 equals the parent in magnitude. Upon a ftridter examination of 

 this egg, it has been difcovered, that the infedi, while in the belly 

 of Its mother, undergoes a transformation into the nymph or chry- 

 falis ftate ; and that, inftead of a worm, a fly is produced from it, 

 of the fame dimenfions as the parent. This difcovery, however, 

 does not diminifli our wonder, that any animal fhould adually give 

 jbirth to a fubftance as large as its own body, and that its Cze fliould 

 never afterwards receive any augmentation *. 



When 



» Reaumur, torn. 6. p. 48. •,— and Bonnet, torn. 3. p. 363. — 369. 



