WE HAVE not finished yet. On careful examination, we find that the male organ, the prolongation of the urethra, with its cavernous walls, is not a simple canal like a rubber tube, for at its end it bears a small head, the glans. This head is-conical in shape, but oblique in the sense that only the inferior or posterior surface is not pointed. On this aspect, the urethra may be palpated as it pursues its straight course. The base of this head has a larger circumference than the penis at any other point and bulges considerably at the point of junction, like a circular swelling. This provision is very important for the movements in coitus firstly as an aid to massage, secondly in view of the external occlusory muscles of the vagina which grip it and prevent its slipping out too easily. In dogs and some related species, such an occurrence is utterly impossible, as this edge is cartilaginous, so that forcible attempts at separation would probably tear the vulva.
The glans is covered by a very delicate transparent membrane, with the typical appearance of a mucous membrane, which merges insensibly into the mucous membrane of the urethra. Internally, the glans consists of the same cavernous tissue as the inferior or posterior surface of the penis, where the urethra may be palpated. It is therefore not so stony hard as the rest of the penis, even when swollen. This is very fortunate, for otherwise the first attempt at copulation might often result in damage to the urethra and bladder, or perforation of the vaginal wall.
In the flaccid condition, however, the glans is not very noticeable, of small dimensions and not conspicuously different from the cylindrical portion of the penis. There is one more point to note. It is due to the nature of the cavernous tissue that the penis varies so greatly in size with the blood pressure. Sometimes, it is very large; at others, especially during excessive cold or after loss of blood, it may become extremely small. But how about the skin? Is it tight, almost to bursting, at one time, and at others almost inconveniently wrinkled? One need only think of the voluminous- folds of a bellows or a camera. Nothing of this sort is found in the penis. Nature shames our machines with her simple-devices.
Her solution of the problem is so simple that scarcely anybody has realised its difficulty. The skin lies nearly always smoothly disposed round the penis. The temporary surplus is taken up at either end. The skin of the scrotum can be wrinkled in the finest corrugations, like the most delicate crepe paper, by minute muscular fibres, and during erection these fine wrinkles are to some extent smoothed out. As soon as the penis returns to its usual size, the scrotal wrinkles reappear. Sometimes, when the muscles are quite relaxed, the scrotum may hang lower than the penis. When the penis is fully erect, the scrotum disappears altogether, and the two testicles lie close against the penis. Thus the same portion of skin may be used for both organs.
At the other end of the penis, however, i.e., on the glans; the skin has lost its mobility, hut as recompense we find, at the margin of the. glans, just behind its projecting rim, a single large fold which is large enough to hide the whole g ans. In this case, the fold of skin is a double one. Urine, after leaving the end of the urethra, must pass through this fold of skin (the prepuce) before it actually reaches the exterior.
In the erect position the glans is mot exposed, and the fold of skin disappears almost entirely. In a very flaccid condition, however, due to cold, loss of blood, or age, the prepuce entirely surrounds the glans, as though to protect it.
In the female the clitoris is similarly supplied with a prepuce. The little protrusion known as the clitoris is not, however, quite covered by it. Here the foreskin is a very small fold of mucous membrane which hides about half the clitoris on its anterior (in the supine position the superior) aspect. On either side the fold merges into the two small folds of mucous membrane known as the nymphae. Covering all this are the labia majors which merge posteriorly into the buttocks so that in the adult they appear to be an anterior hirsute prolongation of them.
If we compare the two sexes in this respect we shall see that the female form with its freedom from protuberances is more closely related to the original type common to both sexes.
However, even in the female protuberances are sometimes found, especially prolongations of one or both of the nymphae. In exceptional cases, prolapse may bring about a prolongation of the female urethra. I once found extroversion of the urethra in a female to such an extent that it resembled an enormously elongated clitoris.
A great enlargement of the clitoris is said to be frequent in certain lands. This is a form of rivalry the male does not seem to appreciate, for in many tribes(1) there prevails the custom of shortening or amputating the clitoris by operation.
On the other hand there are tribes who by means of sucking or stings of insects aim at enlarging the clitoris as far as possible. Here and there attempts are made and with some success, artificially to lengthen the labia majora by pulling on them or suspending weights from them (cf. Hottentot aprons obtained by this means).
Generally, however, prolongations are reserved for the male sex. In the male, through natural selection the prolongation and swelling of the genital canal has become a normal phenomenon, because of its great advantages in the struggle for existence.
In the female on the other hand it has become a rare exception.
The enlargement of the male copulatory organ has gradually accommodated itself to the female dilatation, and vice versa.
Not only the mental characteristics, but physical conformations as well have become mutually adapted in man and woman. Matter has far more inertia than spirit and so bodily adaptation in pre-historic times has taken much longer.
1 For a small penis to occur in females it would be necessary for both clitoris and urethra to be greatly enlarged and to coalesce. This would be the female equivalent of hermaphrodite-formation in males.