In the controversy as to the woman question, appeal has been made to the arbitration of anatomy, in the hope that by that aid a line could be drawn between those characters of males or females that are unalterable because inborn, and those that are acquired. (It was a strange adventure to attempt to decide the differences between the natural endowment of men and women on anatomical results; to suppose that if all other investigation failed to establish the difference, the matter could be settled by a few more grains of brain-weight on the one side.) However, the answer of the anatomists is clear enough, whether it refer to the brain or to any other portion of the body; absolute sexual distinctions between all men on the one side and all women on the other do not exist. Although the skeleton of the hand of most men is different from that of most women yet the sex cannot be determined with certainty either from the skeleton or from an isolated part with its muscles, tendons, skin, blood and nerves. The same is true of the chest, sacrum or skull. And what are we to say of the pelvis, that part of the skeleton in which, if anywhere, striking sexual differences exist? It is almost universally believed that in the one case the pelvis is adapted for the act of parturition, in the other case is not so adapted. And yet the character of the pelvis cannot be taken as an absolute criterion of sex. There are to be found, and the wayfarer knows this as well as the anatomist, many women with narrow male-like pelves and many men with the broad pelves of women. Are we then to make nothing of sexual differences? That would imply, almost, that we could not distinguish between men and women.

From what quarter are we to seek help in our problem? The old doctrine is insufficient, and yet we cannot make shift without it. If the received ideas do not suffice, it must be our task to seek out new and better guides.

CHAPTER I
“MALES” AND “FEMALES”

In the widest treatment of most living things, a blunt separation of them into males or females no longer suffices for the known facts. The limitations of these conceptions have been felt more or less by many writers. The first purpose of this work is to make this point clear.

I agree with other authors who, in a recent treatment of the facts connected with this subject, have taken as a starting-point what has been established by embryology regarding the existence in human beings, plants, and animals of an embryonic stage neutral as regards sex.

In the case of a human embryo of less than five weeks, for instance, the sex to which it would afterwards belong cannot be recognised. In the fifth week of fœtal life processes begin which, by the end of the fifth month of pregnancy, have turned the genital rudiments, at first alike in the sexes, into one sex and have determined the sex of the whole organism. The details of these processes need not be described more fully here. It can be shown that however distinctly unisexual an adult plant, animal or human being may be, there is always a certain persistence of the bisexual character, never a complete disappearance of the characters of the undeveloped sex. Sexual differentiation, in fact, is never complete. All the peculiarities of the male sex may be present in the female in some form, however weakly developed; and so also the sexual characteristics of the woman persist in the man, although perhaps they are not so completely rudimentary. The characters of the other sex occur in the one sex in a vestigial form. Thus, in the case of human beings, in which our interest is greatest, to take an example, it will be found that the most womanly woman has a growth of colourless hair, known as “lanugo” in the position of the male beard; and in the most manly man there are developed under the skin of the breast masses of glandular tissue connected with the nipples. This condition of things has been minutely investigated in the true genital organs and ducts, the region called the “urino-genital tract,” and in each sex there has been found a complete but rudimentary set of parallels to the organs of the other sex.

These embryological conclusions can be brought into relation with another set of facts. Haeckel has used the word “gonochorism” for the separation of the sexes, and in different classes and groups of creatures different degrees of gonochorism may be noted. Different kinds of animals and plants may be distinguished by the extent to which the characters of one sex are rudimentary in the other. The most extreme case of sexual differentiation, the sharpest gonochorism, occurs in sexual dimorphism, that is to say, in that condition of affairs in which (as for instance in some water-fleas) the males and females of the same species differ as much or even more from each other as the members of different species, or genera. There is not so sharply marked gonochorism amongst vertebrates as in the case of crustacea or insects. Amongst the former there does not exist a distinction between males and females so complete as to reach sexual dimorphism. A condition much more frequent amongst them is the occurrence of forms intermediate in regard to sex, what is called abnormal hermaphroditism; whilst in certain fishes hermaphroditism is the normal condition.

I must point out here that it must not be assumed that there exist only extreme males with scanty remnants of the female condition, extreme females with traces of the male, hermaphrodite or transitional forms, and wide gaps between these conditions. I am dealing specially with human beings, but what I have to say of them might be applied, with more or less modification, to nearly all creatures in which sexual reproduction takes place.

Amongst human beings the state of the case is as follows: There exist all sorts of intermediate conditions between male and female—sexual transitional forms. In physical inquiries an “ideal gas” is assumed, that is to say, a gas, the behaviour of which follows the law of Boyle-Gay-Lussac exactly, although, in fact, no such gas exists, and laws are deduced from this so that the deviations from the ideal laws may be established in the case of actually existing gases. In the same fashion we may suppose the existence of an ideal man, M, and of an ideal woman, W, as sexual types although these types do not actually exist. Such types not only can be constructed, but must be constructed. As in art so in science, the real purpose is to reach the type, the Platonic Idea. The science of physics investigates the behaviour of bodies that are absolutely rigid or absolutely elastic, in the full knowledge that neither the one nor the other actually exists. The intermediate conditions actually existing between the two absolute states of matter serve merely as a starting-point for investigation of the “types” and in the practical application of the theory are treated as mixtures and exhaustively analysed. So also there exist only the intermediate stages between absolute males and females, the absolute conditions never presenting themselves.