CHAPTER III 



INFLUENCE OF HORMONES ON DEVELOPMENT 

 OF SOMATIC SEX-CHARACTERS 



WE have next to consider what are commonly called 

 secondary sexual characters. These are characters 

 or organs more or less completely limited to one 

 sex. When we distinguish in the higher animals 

 the generative organs or gonads on the one hand 

 from the body or soma on the other, we see that 

 all differences between the sexes, except the gonads, 

 are somatic, and we may call them somatic sexual 

 characters. The question at once arises whether 

 the soma itself is sexual, that is to say, whether on the 

 assumption that the sex of the zygote is already 

 determined before it begins to develop, the somatic 

 cells as well as the gametocytes are individually 

 and collectively either male or female. In previous 

 discussions of the subject I have urged that the 

 only meaning of sex was the difference between the 

 megagamete or ovum, and the microgamete or sperm. 

 But if the zygote, although compounded of ovum 

 and sperm, is predestined to give rise in the gametes 

 descended from it, either to sperms only or to ova 

 only, it may be suggested that all the somatic cells 

 descended from the zygote are likewise either male 

 or female, although they do not give rise to gametes. 

 It is evident, however, that the somatic cells, organs, 

 and characters do not differ necessarily or universally 



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