M^ THE PHILOSOPHY 



the aid of experience, could believe it to have been proctiiced 

 by this infecl. When the egg is hatched, a fly proceeds 

 from it, which, at the moment of birth, equals the parent in 

 magnitude. Upon a ftrifter examination of this egg, it has 

 been difcovercd, that the infeft, v^^hile in the belly of its 

 niotheir, undergoes a transformation into the nymph or chry- 

 falis ftate j and that, inftead of a worm, a fly is produced 

 from it, of the fame dimenfions as the parent. This difcov- 

 ery, however, does not diminifli our wonder, that any ani- 

 mal ihould actually give birth to a fubftance as large as its 

 own body, and that its fize fliould never afterwards receive 

 any augmentation*. 



When caterpillars, fome time before their change, are de- 

 prived of food, they diminifh to at leaft one half of their 

 former flze. Their chryfalids, of courfe, as well as the but- 

 terflies which proceed from them, are proportionally fmalU 

 From this fa£l we learn the importance of feeding all young 

 animals well till they acquire their full growth. 



It is a remark of the ingenious Reaumur, that fuch In- 

 fects as feed upon dead carcafles, and whofe fecundity Is 

 great, never attack live animals. The fiefh-fly depoflts her 

 eggs in the bodies of dead animals, where her progeny re- 

 ceive that nourifliment which is befl: fuited to their conilitu- 

 tlon. But this fly never attempts to lay her eggs In the 

 fiefh of found and living animals. If Nature had determin- 

 ed her to obferve the oppoflte conduct, men, quadrupeds, 

 and birds, would have been dreadfully a£BI(Sl:ed by the ravag- 

 es of this Angle infect. Left it might be Imagined that the 

 flefli-fly felected dead, inftead of live animals^ becaufe. In 

 depofiting her eggs, fhe was unable to pierce the flcin of the 

 latter, M. de Reaumur made the following experiment, which 

 removed every doubt that might arife on the fubjecSV. He 

 carefully pulled off all the feathers from the thigh of a young 



ind Eonner, torn, 3. p. 363. — 369. 



