in the Animal Kingdom. 355 



have a common origin as processes, and take the same general 

 direction, out of corresponding lamina? of the germinal mem- 

 brane or tubes, and they have the same manner of develop- 

 ment ; but, just as parts of structure, at first common essen- 

 tially to the class, become afterwards transformed, so do the 

 sexual organs, which, essentially, are at first common to the 

 species ; and a difference in function follows. But from the 

 first, as said before, development proceeds according to the 

 sum of the innate formative properties, sexual properties being 

 included in this sum; though their influence on development be 

 not at first appreciable. 



Let the point A, Fig. 13, represent the supposed fundamental 

 form, essentially the same in all animals, so long Fig. 13. 

 as a merely animal structure is manifested. Two 

 germs belonging to the same species, but of differ- 

 ent sexes, start in their development from this 

 point A. Their divergence in development is small, 

 because occasioned by two influences only ; one of 

 which is sex, the other, individuality. At the 

 points BC, sexual peculiarities, local as well as 

 general, exercise more sensibly their sway ; and 

 further development takes them, respectively, to 

 the points DE. Here, if castration terminate the 

 reproductive faculty in both, the result is, not 

 indeed the attainment of, for that is now impos- 

 sible, but, an approximation to, the mean state, 

 FG, which these individuals, respectively, would 

 have reached, had development been influenced, 

 not by sex, but, by individuality alone ; the points 

 H I being now attained. This we conceive may 

 serve rudely to illustrate, what really takes place in nature. 



It follows from the above, that we cannot adopt the theory 



proposed in the Edinburgh Journal of Science for 1829-30 ; 



that " there are, fundamentally, male and female organs in the 

 same being, or originally in all embryos, elementary yet distinct 

 parts, out of which both sets of organs may be formed by deve- 

 lopment." It is the sum of the innate susceptibilities of struc- 

 ture, that determines the direction taken in the development of 

 every germ. Development must therefore from the first, have 

 reference to the sex, as well as to the variety, species, genus. 



