From the seminal vesicles a very short and narrow(7) canal leads downward on each side to the urethra, the posterior wall of which they pierce close together.
This point where the two seminal canals join the urethra is surrounded by an enlargement, the prostate, about the shape and size of a chestnut. It can be palpated through the anus, in the anterior wall of the rectum.
The function of this organ is unknown. It contains many microscopic unstriped muscle-fibres and many delicate glandular ducts, which open into the urethra, into which they pour a mucous secretion which seems to cause the special odour of semen. Certainly the contents of the seminal vesicles are odourless. It is on account of this secretory function that it is called the prostatic (presiding) gland, although the organ appears more like a rudimentary uterus, just as generally rudiments of the duct-system of the opposite sex are found in each sex. As in the female organism the two oviducts join behind the bladder to form a uterus, so in the male the prostate gland is situated at the posterior wall of the urethra just at the point where the two sperm-ducts join. The prostate is only el importance on account of its proneness to enlargements, tumours, calculi (similar to gall stones and renal calculi) and chronic inflammations, which often cause constriction of the urethra in elderly men, and render extensive operations necessary.
Immediately below the prostate, the male urethra pierces the perineal muscular layer in order to gain the exterior. This muscular layer, however, is not as yielding as the anterior muscle-layer in the groin through which the testicles migrated. Moreover, in the male the opening in the muscular layer is not directed downwards (the shortest way) but slantingly forwards; thus the muscular action is more forcible in the male. As soon as it emerges from the pelvic floor the canal bends upwards along the external surface of the pubic bone (in the erect posture the inferior surface of the pubic bone). It is firmly united to the os pubis by connective tissue, and emerges finally on the anterior surface of the body, from which it hangs down for more than a finger’s length immediately anterior to the scrotum which to a certain extent it hides.
When in the flaccid condition, looked at from the right, the male genital canal from the bladder onwards, describes a double curve like the letter S. The os pubis is situated in the first curve. It is this external continuation which, as we shall see in the next chapter, has to function in copulation, and is therefore called penis or male organ. In the same way in woman the lower portion of the genital canal, i.e., vagina and vulva, are termed female copulatory organs. But since in the male the latter portion of the genital canal has to serve for the excretion of urine as well, we refer to the urethra when the canal itself is meant as if it only served for the urinary purpose; this even after puberty.
It is extraordinary that while the female canal has widened as much as possible, the male canal has lengthened as much as possible. Firstly the two sperm-ducts are enormously elongated within and without the abdominal cavity, owing to the descent of the testicles, and at the other end we have the very vascular prolongation at the outlet. Even the seminal vesicles are only elongated narrow structures.
It is extremely remarkable how the male genital canal is related to the abdominal cavity. As far as we are conscious of it, the physiological function of the sexual life has its starting point in the abdominal cavity, but the formation of sperm-cells, which is the most important function, takes place outside the abdominal cavity. It is only the secretory function which proceeds from the abdominal cavity, and it is of this function only that we are conscious. So it is not to be wondered at that up to the present the sexual function has been considered as entirely glandular.
Finally we must notice the peculiar way in which the male genital canal pursues its path through the abdominal cavity. From the testicles to the prostate it is paired and passes above the os pubis. From thence onward it is unpaired and passes below the os pubis. That makes in all three long canals, whose meeting point is situated at the neck of the bladder and which all three protrude for an equal distance outside the body. So it happens that the two sites of formation of the sperm-cells and the site of their ejection are quite close together. And vet this small journey of the sperm-cells touches all hearts and supplies the magic by which Nature rules the whole world, as Schiller says so succinctly in “Die Weltweisen:” (The Worldly Wise).
Until the world is guided entirely by philosophy It will be driven by hunger and by love.
We shall discover in the further course of this book how this mystery is brought about.
7 It is significant that the orifices of the two seminal ducts are so very narrow. Those sperm-cells which have not been stored in the seminal vesicles are subjected to a sphincter-like elastic resistance when they are ejected together with the complex contents of the seminal vesicles.