DIFFERENT SYSTEMS. 141 



exifts in the egg of the mother, how fhould the 

 child refemble its father ? And, if the fpcrmatic 

 worm of a horfe, or the egg of a (he-afs, be the 

 origin of the foetus, how fhould the mule par- 

 take of the nature and figure both of the horfe 

 and afs ? 



Thefe general objections, though perfedly 

 invincible, are not the only difficulties with 

 which both lyftems are embarrafled. May it 

 not be demanded of thofe who embrace the ver- 

 micular lyftem, how thele worms are tranf- 

 formed, and vv herein confifts the analogy be- 

 tween this transformation and that which inieCts 

 undergo ? The caterpillar which is to become a 

 butterfly, paifes through a middle Hate, and, after 

 it ceal'es to be a chrylaiis, is completely formed, 

 has acquired its full growth, and is inlhintly 

 capable of generating : But, in the pretended 

 transformation of the Ipermatic worm of a man, 

 there is no middle or chryfalis ftate ; and, fup- 

 pofing it fhould happen during the firft days of 

 conception, why is not the producOiion of this 

 chryfalis, in place of an unformed embryo, a 

 perfedt adult ? Here all analogy ceafes ; and, of 

 courfe, the notion of the transformation of the 

 fpermatic worm can receive nofupport from this 

 quarter. 



Befidcs, the worm which is to be transformed 

 into a flie proceeds from an egg ; this egg i-s 

 impregnated by the copulation of the male and 

 female, and it includes the foetus which is to pafs 



into 



