THE GONADS

(Sexual, Puberty or Interstitial Glands)

The gonads is the name applied to the generative or reproductive glands considered collectively.  In the male, they are the testes; in the female, the ovaries.  They are, therefore, sometimes called the sexual glands.  As they possess definite canals for the removal of their gross secretion, the specific reproductive cells, ova or spermatozoa, to a surface of the body, they are first of all glands of external secretion.  But they have been also found to hold secretory cells not concerned with the making of the reproductive corpuscles, but, as all the evidence indicates, with the manufacture of an internal secretion.  These interstitial cells form the interstitial gland.  A classic example of a gland of internal secretion lodged in the interstices of a gland of external secretion is thus furnished by the gonads.

ORIGIN OF SEX TRAITS

The history of sex goes back far in the scheme of life.  The immortality of the ameba was at one time one of the indisputables of biology.  Then some observations were made which threw doubt upon a long accepted fact, now declared a dogma.  Lately, opinion has veered back to immortality.  But in the case of a close relative of the ameba, the one-celled animal known as the paramecium, union with another paramecium, true conjugation, has been proved necessary to prevent death sooner or later.  Sex here appears in its most primitive form, on the basis of exchange of necessary materials, between individuals to prevent death, their own having been, so to speak, worn out, in the course of metabolism.

Specifically different sexes come later, when mortality is a universal fate, as a means of rebirth and escape from death.  Then the sexes develop their latest function, most prominent among the younger vertebrates, of acting as nature’s most potent method of variation and differentiation.  In the pursuit of the different, nature has exalted sex, and the intensity of the sex life.  As far as the preservation of a species is concerned, and the reproduction of the individual, the asexual methods, budding, for example, would have done well enough.  But when it comes to enacting a different individual apart from the effects of environment, sex stands out as the favored method of Life.

The development of the sexes and the sexual life brought a new element of conflict into the living world.  Before the advent of the sexes the conflict was essentially for the means of existence, food alone.  But with the sexual life came a conflict for sex pleasure, a competition among members of the same species for the same individual as their sex partners.  The result was the introduction of a factor in evolution which Darwin examined so closely in the “Descent of Man.”