and sperm into relation with our real knowledge of the sex-chromosomes and
their behaviour in reduction and fertilisation.



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 in
the two sexes. On the one hand, we have extraordinary and very conspicuous
peculiarities in the male, entirely absent in the female, such as the