OF MULES. 15 



I have often endeavoured to Inveftigate the rea- 

 fon why any religion, or any government, 

 fhould prohibit the marriage of brothers and 

 fifters. Did men learn, by very ancient expe- 

 rience, that the union of brother and fifter was 

 lefs fertile than an intermixture with ftrangers, or 

 that the former produced fewer males, and 

 feebler and more unhandfome children ? It is 

 certain, however, that, from a thoufand experi- 

 ments, both in men and the other animals, 

 crofling the breed is the only mode of ennobling 

 and preferving the perfection of the fpecies. 



To thefe fads and experiments, let us add 

 what the ancients have faid upon this fubjedt. 

 Ariftotle tells us, that the mule engenders with 

 the mare, r^nd that the jundion produces an ani- 

 mal which the Greeks called hinnus or ginnus. 

 He likevvife remarks, that the rtie-mule cafily 

 conceives, but feldoni brings the foetus to per- 

 fedion *. Of thefe two fads, the fecond is more 

 rare than the firft ; and both happen only in 

 warm climates. M. de Bory, of the royal aca- 

 demy of Sciences, and formerly governour of 

 the American iflands, communicated to me a re- 

 cent fad of this kind, in a letter, dated May 7. 

 1770, of which the following is an extrad. 



' You will perhaps recoiled. Sir, that M. 

 ' d'Alembert read, laft year, in the Academy of 

 * Sciences, a letter, which informed him, that 

 ' a fhe-mule, in the illand of St Domingo, 



* Arift. hifl. animal, lib. 6. cap. 24. 



