Spermatheca

“ The spermatozoön, the principle of life contributed by the male, is so small that it is not visible to the eye except by the aid of a microscope, and, when seen, somewhat resembles a pollywog. These minute centres of life are alive, and move in a fluid which is secreted by the male organs of reproduction, and which is generally called semen. Now, if we study the characteristics of the ovum and of the spermatozoön we may be surprised when we discover some of the same differences which characterize men and women from infancy to old age. ”

“ The human spermatozoon measures about one six-hundredth of an inch in length. It is composed of protoplasm, the substance of which all living creatures are composed. The spermatozoa are believed to be developed from a parent sperm-cell, by the process of segmentation or subdivision, which process is common to all cell-life. The numerous spermatozoa dwell in a gelatinous substance, which, mingling with the other fluidic secretions of the glands of the male, constitutes the male seminal fluid, sperm, or semen, which is ejaculated by the male during the process of copulation. ”

“ Fecundation results and conception ensues, the ovum then remaining attached to the walls of the Uterus, and in time develops into the foetus. If, however, the ovum is not impregnated, because of absence of copulation or from other causes, it gradually loses its vitality, and is finally cast off with the several uterine secretions.
It should be explained here that the "spermatozoon" of the male (the plural of the term is "spermatozoa") is the male generative "seed." The sperum, semen, or seminal fluid of the male is filled with hundreds of thousands {29}of spermatozoa. ”

“ There does not appear to be any true copulation. The male deposits small, white, oval spermatophores, which consist of small bundles of spermatozoa cemented together by some glutinous substance, indiscriminately on any part of the body of the female. Such spermatophores are found on the bodies of both males and females from July to January, but they appear to be most numerous in our autumn. It seems probable that the spermatozoa make their way from the adherent spermatophore through the body wall into the body, and so by traversing the tissues reach the ovary. ”

“ It is incorrect to suppose, as has been held by some{121} theorists, that one testicle give rise to male spermatozoa and the other to female spermatozoa, for both male and female offspring have been produced from the same male parent after one testicle or the other has been removed. The same is true in cases in which either ovary has been removed from the mother; that is, male and female offspring are produced from mothers in whom either ovary has been removed. ”

“ Many of the spermatozoa, weaker than the others, perish on the way, and only a few continue the journey up through the uterus to the tube. When near the little ovum, which remains passive, their movements become more and more rapid, they seem to be attracted to it as if by a magnet, and finally one spermatozoön—just one—the one that happens to be the strongest or the nearest, makes a mad rush at it with its head, perforates it, and is completely swallowed up by it. ”

“ The whole body of the babe is developed from the ovum or female element after it has been fertilized by the spermatozoon or male element. The union usually takes place in the tube. The spermatozoon, after being deposited in the vagina, travels to the mouth of the womb, then up through the womb into one of the tubes. Here it meets the ovum and unites with it, then the impregnated ovum continues on its way to the uterus. It attaches itself to the lining of the womb by little thread-like filaments which it projects. ”

“ On the other hand, there is considerable evidence that the ovum has some share in the effect, and if this is so, before any practical results are reached it will be necessary to discover which of two conceivable causes of sex-determination is the true one. It is possible that there are two kinds of ova, as well as two kinds of spermatozoa, and that there is a selective fertilization of such a kind that one kind of spermatozoon only fertilizes one kind of ovum, the second kind of spermatozoon the second kind of ovum. ”

“ These defects in spermatogenesis are of course evidenced in the semen by the presence of immature, or abnormal types of sperms. With cessation of spermatogenesis or degeneration of the epithelium of the entire gland, no sperms are formed. Not infrequently one finds numerous tubules, or even the entire testis in which the germinal epithelium is intact, but there is little or no evidence of mitosis, as in some tubules of Bull 6. The cells are several layers deep as in the normal condition, but they are not dividing. ”

“ But nature is lavish where the propagation of the species is concerned. A portion of an ovary or of both ovaries might become diseased, and thousands of ova might become unfit for fertilization; nature therefore puts in an extra reserve supply. We see a still more striking example of this extreme extravagant lavishness in man; only one spermatozoön is necessary to impregnate the ovum, and only one spermatozoön can penetrate the ovum; nevertheless each normal ejaculation of semen contains between a quarter and half a million spermatozoa. ”

“ The spermatozoa do not attain maturity until they reach the uterus of the female.
The internal female reproductive organs are, with few exceptions (Trichina, etc.) , double, but the vagina, which is lined with cuticle continuous with that covering the body, is always single. They are usually much coiled, and may be divided into ovary, oviduct, and uterus. The ova arise from a polynucleated mass of protoplasm or syncytium (Fig. 65, o) at the upper end, and acquire distinctness as they approach the oviduct. ”

“ Since only one spermatozoon enters the ovum, whether or not the child will be a boy or a girl depends entirely upon which type gains entrance. If this explanation is correct, and it is in accord with careful biological observations, it removes from the mother all responsibility for the sex of her child. Furthermore, since the facts indicate that male-producing and female-producing spermatozoa are present in equal numbers, it follows that practically there is an even chance that an embryo will develop into a boy or a girl. ”

“ The more marked the stenosis of the cervical canal, the smaller the passage by which the vagina communicates with the uterus, the more difficult will it be for the passage of the spermatozoa to be effected, so that of the millions of spermatozoa deposited in the neighbourhood of the os uteri, thousands will, as in normal cases, find their way to the uterine orifices of the Fallopian tubes. So much the more, then, is the contact between spermatozoon and ovum rendered difficult, and so much the more unlikely is it that conception will occur. ”

“ Seen under a microscope, a single drop of semen reveals a multitude of spermatozoa swimming about in the prostate-carrying medium. It is in this form that the vitalizing male element meets the female infertile ovum. This mass of live and moving germs is poured all around and about the region in which the ovum lies waiting to be fertilized, and every one of them seems to be "rushing about like mad" to find what it is sent to do, namely, to meet and fertilize the ovum. ”

“ Spermatozoa originate in the testis as cells, which are filled with granules. After a time, each granule acquires a long appendage, and then the cell has become converted into a bundle of small zoösperms. Development still continues, until finally the thin pellicle on the outside of the bundle is ruptured, thus liberating the young spermatozoa, which speedily complete their full development. The spermatozoön is pure protoplasm, which is the basis of all life, and its power of spontaneous motion is due to this fact. ”

“ Now fertilisation does not necessarily occur whenever the male organ comes in contact with the female organ. Fertilisation occurs only when a male-cell (spermatazoon) unites with a female-cell (ovum) ; in other words, when the spermatazoa in the seminal fluid of a man meet and unite with the germ or ovum in the body of a woman. That is the beginning of the child. This union of the two cells need not take place during or immediately after sexual intercourse. It may occur many hours, or even two or three weeks, after connection, because the spermatazoa have motion of their own. ”

“ It is much easier to understand why abnormal spermatozoa occur so frequently, or changes take place in the semen with death or weakening of the germinal elements, if we realize or stop to consider the highly differential process of spermatogenesis, and the various structures which contribute to the formation of the semen. We must come to realize that each part of the genital tract is essential to the normal functioning of the whole, and that the genital tract and reproduction are in turn dependent upon the proper functioning of the entire body. ”

“ The semen, made up as it is of mixed products of the testes and accessory sexual glands, is very often abnormal, as would be expected in view of the frequency with which changes occur in the glands contributing to its formation. The normal semen is remarkably adapted to its function of nourishment and stimulation of the spermatozoa, and their conveyance to the internal female genital organs. The spermatozoa are extremely sensitive to changes in their environment, with the result that any alteration of the physical or biochemical content of the seminal fluid may cause death of the sperms. ”

“ In his opinion the determination of the sex of the embryo depends neither upon the quality of the ovum nor upon that of the spermatozoon, nor again upon the reciprocal influences exerted by ovum and spermatozoon on one another. During the earliest time after fertilization the embryo is sexually neutral and only later, as a result of some new influence acting upon it, does it receive an impulse toward the formation either of the male or of the female sex. ”

“ That of the male is called the spermatozoon (pronounced sper ́ma-to-zoön) . It is sometimes called spermatozoid; the plural is spermatozoa. It is exceedingly small, the smallest of any cell in the body, and has the power to move from place to place. These cells are produced in enormous numbers, and so far as they have been observed under the microscope they differ considerably in power of movement and in perfection of development. Considering their small size, they must make a [163] very long journey to find the ovum; and if they were only few in number, they would rarely succeed ”

“ The ovum may remain for a period, and the spermatozoa that seek the ovum may enter, but neither may tarry unless each yields itself to the other in that mysterious union which results in life. Apart or alone, after a brief period, they must alike be cast out; no idler may tarry there; but that semblance to innate intelligence which rejects or casts out any incomplete part as a foreign substance accords a hearty welcome to the ovum that has been quickened into a new life by the entrance of a spermatozoön. ”

“ For, while I can see no theoretical difficulty in supposing that “the carriers of heredity,” when set free by the disintegration of their containing spermatozoa, may reach the unripe ova while still embedded in the depths of the ovary, I do see a difficulty, amounting almost to a physiological impossibility, in supposing that a whole spermatozoon can perform such a feat. ”

“ The moment that the real body of the ovum is penetrated by the successful spermatozoon, a tough covering or thick membrane forms around the ovum and thus prevents the entrance of other spermatozoa. The successful spermatozoon then loses its tail, and the remaining head and body become what is known as "the male pronucleus." ”

“ Spermatocytes and spermatids are seen in the more severe types of defective spermatogenesis, and are relatively uncommon, while the more mature forms that result from the transformations of spermatid to adult cell are very often seen. ”

“ When spermatozoids are kept for half an hour in the chloral solution, a more decided paralysis will be observed, which persists for some time after the removal of the poisonous agent. A few minutes elapse before some of the spermatozoids exhibit feeble movements which finally become active. Even when placed near ova, it is some time before they fertilize them, although several may [57] attach themselves to the egg’s surface. But, finally, fertilization does take place by the penetration of one spermatozoid, and the egg normally develops. ”

“ Hence, when the ovum is male, only a male spermatozoön will be admitted within its interior, and a boy will be the result. If the ovum is female, only a female spermatozoön will be able to penetrate it, and a girl will be born. ”

“ The spermatozoid which reaches the egg cell first would seem to be the one which causes fecundation. That one which is utilized in fecundation swims into the cytoplasm of the egg cell for a short distance, where it comes to rest and undergoes change. The nucleus slips out of its cytoplasmic sheath and passes on alone from this point to the egg nucleus, with which it unites. The spiral ciliferous band, which forms such an interesting part of the spermatozoid, remains at the apex of the egg cell in the place where the nucleus left it. ”