286 OF THE FORMATION 



particles of the male and female mix at the time 

 of conception ; becaufe we often fee children 

 who refemble both father and mother : And, 

 what confirms this theory is, that all the particles 

 common to the two fexes mix together promif- 

 cuoufly, but that the particles peculiar to the 

 fexes never mix ; for we daily perceive children 

 with eyes refembling thofe of the father, while 

 their mouth and front refemble thofe of the 

 mother. But we never fee any fuch mixture of 

 refemblances in the fcxual parts; we never find, 

 in the fame individual, the tefticles of the father 

 and the vagina of the mother. 

 The formation of the foetus, therefore, is ef- 

 \ feded by the mixture of the organic particles of 

 both fexes; and this mixture fixes or gives a lo- 

 cal eftablifhment to the particles, becaufe it is 

 made according to the laws of affinity which 

 take place between the different parts, and which 

 determine the particles to arrange themfelves in 

 the fame order they obferved when they exifted 

 in the individuals who furnifhed them. The 

 particles which proceed from the head, for ex- 

 ample, cannot, according to thefe laws, take up 

 their ftation in the legs, or in any other part 

 but the head of the foetus. All the particles are 

 in motion when they firft unite ; and this mo- 

 tion muft be round the point or centre of union. 

 This bafis or central point, which is neceflary 

 to the union of the particles, and which, by its 

 reaction and inertia, fixes and deflroys their ac- 

 tivity, 



