Spermatozoid

“ It is well known that the mental characteristics of the father are transmitted through the spermatozoid, and that, therefore, the molecular movements which produce the mechanism of such mental characters must exist in the spermatozoid. But the material of the spermatozoid is combined with that of the ovum, and the embryo is compounded of the animal contents of both bodies. In a wonderful way the embryo develops into a being which resembles one or both parents in minute details. ”

“ In the Algae, such as Fucus, Volvox, Oedogonium, Bulbochaete, and in the Fungus Monoblepharis, the spermatozoid is a small oval or elongate cell containing nucleus, cytoplasm and sometimes plastids. In the Characeae, the Vascular Cryptogams, in Zamia and Cycas, and in Ginkgo, the spermatozoids are more or less highly modified cells with two or more cilia, and resemble in many respects, both in their structure and mode of formation, the spermatozoids of animals. ”

“ Another feature of importance in the spermatozoid formation of Zamia is the metamorphosis of the entire spermatid cell into a spermatozoid. In the writer's preliminary papers it was pointed out that when the central cell divides to form the spermatids a plasma membrane is formed entirely across the cell, and that in the transformation of the two daughter cells or spermatids into the spermatozoids these cells are transformed directly into the spermatozoids without the formation of a new plasma membrane. ”

“ 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 ”

“ 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. ”

“ The signs furnished by the genital organs of the male are of less importance. Atrophy and diminished weight of the testicles and rarity or absence of the spermatozoids are indications of senility; although spermatozoids have been observed at ninety-four years. The structure of the spermatic cord at different periods of life from the last of intra-uterine to the first of extra-uterine life, in puberty, and in old age, is accompanied by characteristic modifications of development and regression, which are of interest on the question of medico-forensic diagnosis of identity, as shown by Dr. ”

“ In most cases which have been investigated the divisions by which the spermatids arise from the spermatocytes are two in number, so that each spermatocyte gives origin to four spermatids. Each spermatid becomes a functional spermatozoon or male gamete. The gametogeny of the male therefore closely resembles that of the female, differing from it only in the fact that all the four products of the progamete become functional gametes, whereas in the female only one, the ovum, becomes functional, the other three (polar bodies) being abortive. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ In normal fertilization, as a rule, only one spermatozoon fuses with the ovum. It has been observed in some eggs that a membrane, formed round the ovum immediately after the entrance of the spermatozoon, prevents the entrance of others. If Gametogeny. than one spermatozoon enters, a corresponding number of male pronuclei are formed, and the subsequent development, if it takes place at all, is abnormal and soon ceases. An egg by ill-treatment (influence of chloroform, carbonic acid, &c.) can be made to take more than one spermatozoon. ”

“ 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. ”

“ In the sperm-cell there occurs just that failure in the production of chromatin which, according to the hypothesis above sketched out, is to be expected; for, in the process of cell-multiplication, the cells which become spermatozoa are left with half the number of chromosomes possessed by preceding cells: there is actually that impoverishment and declining vigour here suggested as the antecedent of fertilization. It needs only to imagine the ovum and the polar body to be alike in size, to see the parallelism ”

“ 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. ”

“ 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. ”

“ On this theory the determination of sex depends upon the period at which, after its liberation from the follicle, the ovum encounters a spermatozoon; the ovum which is fertilized early in its career becomes a female embryo; the ovum, on the other hand, which is not fertilized until it has become comparatively old, becomes a male embryo. But, as Hensen points out, a spermatozoon, according to its condition, may either fail sufficiently to fortify an ovum which itself is in good condition; or, on the other hand, a powerful spermatozoon may fortify an ovum of deficient vitality. ”

“ 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. ”

“ The spermatozoon is one of the smallest of known cells, frequently being no more than one hundred thousandth of the size of the ovum, although the extraordinary case of a small Cypris has been recorded in which the spermatozoa are longer than the animal. It is produced in enormous quantities and relatively to other minute cells is extremely tenacious of life. It may retain its vitality in the male organism for a long time after it has become a separate cell, and may exist for lengthy periods in the female organism. ”

“ In the male the testis is a specialized portion of the wall of the genital coelom, and has a structure comparable to that of the ovary. The spermatozoa pass through an orifice from the cavity of the testis to the genital capsule, and thence to the spermiduct. The spermiduct is provided with a glandular pouch, and opens into a terminal reservoir known as Needham’s sac or the spermatophore sac. The function of this pouch is to form the spermatophore, which is an elastic tube formed of structureless secretion and invaginated into itself. ”

“ 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 author believes that the ovum draws the spermatozoa toward itself by chemical influence, acting as an attracting stimulus, in a similar manner to the attraction Pfeffer has shown certain chemical substances may have for moving spores; the attractive power of the ovum being annulled or weakened by the formation of the male pronucleus. As a solution of the origin of sexuality the attractive hypothesis is offered that sexuality is coextensive with life; that in protozoa the male and female are united in each of the conjugating cells, and impregnation is double ”

“ In the love episode, at the time when contact is deepest and most intense, one sees, if one reasons biologically, that the time that would be chosen by nature for the injection of spermatozoa (of the millions of which only one is to be chosen by chance to be united to the single ovum ordinarily developed each month) is the time when the container which is destined to be the seat of the future life was either most open or most turned toward the source of the spermatozoa. ”

“ 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. ”

“ The cell nucleus is generally situated near the rounded or pointed extremity, with a centrosome immediately behind it, whilst the scanty protoplasm forms the body and vibratile tail; but there appears to be no general significance in the various configurations that occur amongst different animals. The process of spermatogenesis, or production of spermatozoa from the permanent cells of the testis, varies extremely amongst different animals and has been the subject of many elaborate investigations and much confusing nomenclature. ”