474 GENERAL RESULTS. CHAP. XII 



having thus acquired firmly fixed affinities. However 

 this may be, with the two great classes of cases before 

 us, namely, those relating to the self-fertilisation and 

 cross-fertilisation of the individuals of the same species, 

 and those relating to the illegitimate and legitimate 

 unions of heterostyled plants, it is quite unjustifiable to 

 assume that the sterility of species when first crossed 

 and of their hybrid offspring, indicates that they 

 differ in some fundamental manner from the varieties 

 or individuals of the same species. 



