This section of the book is from "The Complete Herbalist" by Dr. O. Phelps Brown. Also available from Amazon: The Complete Herbalist: The People Their Own Physicians By The Use Of Nature's Remedies.
This is a secretion formed by the testes, which anatomically we have seen are composed of lobules formed of convoluted seminiferous tubes. The number of lobules is about 450 in each testis, and that of tubules about 840. It is apparent, then, that each testis presents a vast extent of surface for the secretion of the spermatic fluid. The testes originate in the lower part of what is called the Woolfian bodies in the embryo, while the kidneys spring from the upper part. They do not descend into the scrotum until about the ninth month, and sometimes one or both remain in the abdomen, without, however, interfering with their function.
The semen is a thick, tenacious, grayish fluid, having a peculiar odor called spermatic, probably dependent on the secretions mixed with it. The semen as ejected is not the same as secreted by the testes, as it receives, in its passage out, the addition of the liquefying secretions of the prostate and Cowper's glands. It is alkaline in reaction, and contains albumen and a peculiar principle called spermatin. It also contains spermatazoids, very small bodies with a tail-like process to them. They were formerly regarded as animalcules, but now known to possess no independent organic life. As viewed under the microscope they are seen floating lively around the spermatic liquor; this is, most probably, due to ciliary vibrations. The semen also contains other minute, granular bodies, called seminal granules. These, in conjunction with the spermatozoids, constitute the formative agents furnished by the male in generation. They are supposed to correspond with the pollen tubes of plants. The vermicular motion of the spermatozoids evidently aids the passage of the semen, after its injection into the womb, to the ovaries of the female, and if they there meet the female elements of generation an ovule becomes impregnated, and pregnancy is the result. The semen is a very vital element, and is only secreted in proportion to the vigor of the male. It contains chlorides and phosphates, hence its waste preys upon the nervous tissue for its supply of phosphorus. The secretion takes place about the fourteenth or fifteenth year, and continues till about sixty or sixty-five, and during the whole of this time is much under the influence of the nervous system. Its presence in the seminal vesicles is required for the proper accomplishment of the virile act, and it is a well-known physiological fact that full procreative quality is only gained after it has been for some time lodged in the vesicles. The involuntary expenditure of this vital fluid is therefore not only detrimental to the general health, but also seriously destructive of procreative capacity.