Human reproduction

“ At this very early age of reproduction the embryo has all the elements of the future man or woman, mentally and physically, even before any form becomes apparent; and so small is the human being at the earliest stage of its existence that no material change is observable between the ovule that contains the product of conception and a fully developed ovule unimpregnated. ”

“ In all the different forms of a-sexual reproduction, from fission to parthenogenesis, the female may in this sense be said to exist alone and perform all the functions of life, including reproduction. ”

“ How should we have imagined the possibility of fertilization for successive generations, of hermaphroditism, or of reproduction by fissure, etc., being found among the methods which Nature adopts for replenishing the earth, had we contented ourselves with an examination of the comparatively simple methods of ordinary sexual reproduction? ”

“ II. That sex is determined in the moment of fertilization by the reciprocal interaction of male and female, of zoösperm and ovum. One variant of this theory maintains that each reproductive element strives for the reproduction of its own sex; that a struggle takes place and that the victor in the contest stamps its own sex-likeness upon the fertilized product. ”

“ It must include all the developmental processes which take place as a result of sexual reproduction. A man at birth, when he ceases to be an embryo, has still many changes besides those of simple growth to pass through. ”

“ Problems of Reproduction.—The problems of reproduction are extremely broad, involving not only the immediate questions of individual reproduction, but also those broader and deeper ones which relate to heredity. ”

“ Comparison shows that there is, on the one hand, no essential distinction between ordinary growth and reproduction by budding, and, on the other hand, none except the necessity for impregnation to distinguish asexual from sexual reproduction. ”

“ Without the Ovaries there would be no ova or eggs, and without the ova there would be possible no reproductive purposes, and therefore no office for the sex organs at all, for reproduction is the fundamental office, function, and purpose of the entire sexual organism. ”

“ As we rise in the scale of organization, animals are more completely developed, and greater economy is displayed in their preservation. The germ passes from the ovary into an organ prepared for its reception and growth, to which, after fecundation, it becomes attached, and where it remains until sufficiently developed to maintain respiratory life. This organ is called the womb, or uterus, and is peculiar to most mammalia. This mode of reproduction is termed viviparous generation. ”

“ In the simplest forms of conjugation the functions of both parents appear to be identical, but in organisms which are a little more specialized we find male and female reproductive bodies, and the offspring is the result of the union of the male element of one individual with the female element of another; that is, we have true sexual reproduction in its simplest form. ”

“ It is an interesting physiological fact that, while the growth and development of the individual are rapidly progressing, the reproductive powers remain almost inactive, and that the commencement of reproduction not only indicates an arrest of growth, but, in a great measure, contributes toward it. ”

“ And the chief facts in reproduction are practically the same wherever the phenomena occur. Here, as everywhere else in the world, when a new life-form appears, it is always the result of the union of two forces, elements, germs or whatsoever. ”

“ A limited number of observations and experiments have been made to test out the correlation between sexual reproduction and variation, but they have so far been too few or too inconclusive to enable us to come to a satisfactory conclusion. ”

“ The reproductive faculty of the males and the females of this distinct and peculiar animal is limited to the generative reproduction of individuals of the same type, by a sexual union of two individuals of that type. ”

“ The ideas which are now entertained respecting fecundation, after the successful congress of the two sexes, in the human species—respecting its seat—respecting the first origin, station, and rudimental creation of the embryo—respecting the journey of the latter into the womb, its sojourn in that cavity, and the various metamorphoses it undergoes therein, up to the period fixed for its projection into the WORLD, may be comprised within a small number of propositions. ”

“ This involves a diminished number of offspring, but an increased amount of time and care in the creation and breeding of each; it involves also that the reproductive life of the organism is shortened and more or less confined to special periods; it begins much later, it usually ends earlier, and even in its period of activity it tends to fall into cycles. Nature, we see, who, at the outset, had endowed her children so lavishly with the aptitude for multiplication, grown wiser now, expends her fertile imagination in devising preventive checks on reproduction for her children's use. ”

“ Sexual reproduction does not essentially differ, as we have seen, from budding or self-division, and these processes graduate through the repair of injuries into ordinary development and growth; it might therefore be expected that every character would be as regularly transmitted by all the methods of reproduction as by continued growth. ”

“ As has already been said, this use of the sex organs, merely to produce progeny, and so insure a continuance of the race, is a quality that mankind shares with all the rest of the animal kingdom. In all essentials, so far as the material parts of the act are concerned, the beginnings of the new life in the human family differ not a whit from that of any other mammals. In each case the ovum is produced by the ovaries of the female, passes into the womb, is there met by the semen from the male, fertilized by the spermatozoa, and so the foetus gets its start. ”

“ Now in this fissiparous mode of multiplication, which "is amazingly productive, and indeed surpasses in fertility any other with which we are acquainted," [11] we see most clearly the antagonism between individuation and reproduction. We see that the reproductive process involves destruction of the individual ”

“ To those who find it difficult to assimilate this somewhat startling idea, we now present a brief statement of the infinitely greater facility toward reproduction manifested by living creatures lacking in sex-differentiation as compared with those possessing it. ”

“ When sex-determination had become possible through centrifuging human sperm to separate the male-producing and female-producing types, most parents decided to have sons, especially for their firstborn. ”

“ As has been already stated in the chapter on Biology, reproduction of the species depends upon the union of a sperm-cell with a germ-cell, the male furnishing the former and the female the latter. It is a well-known fact that the marriage of persons having dissimilar temperaments is more likely to be fertile than the union of persons of the same temperaments; consanguineous marriages, or the union of persons nearly related by blood, diminish fertility and the vigor of the offspring. ”

“ But before closing this chapter upon the complemental differences between the two sexes, it will be interesting to observe some remarkable similarities in the reproductive organs themselves, and to note how, in that infinite wisdom which is marvelous in our eyes, God has so modified their form and office that the external organs of reproduction in man become the internal and seemingly different organs of reproduction in woman. ”

“ From the moment of conception, during the months of gestation, at the time of childbirth and after, changes of great interest take place in the germ of human life and in the body of the mother. Her body is marvelously fitted for the reception and development of the ovum, the embryo and the fetus through the various stages of fertilization, germination, development, maturity, to the time of the eventual exit of the child into the outer world to begin its own independent life. ”

“ Sexual and asexual reproduction are thus seen not to differ essentially; and we have already shown that asexual reproduction, the power of re-growth and development are all parts of one and the same great law. ”

“ Nature calls upon the male animal to make a contribution for procreation, which contribution is, always has been, and, in the very nature of the case, always must be a certain tax upon the powers of the male animal. When the intercourse is indulged for procreation only, the male animal can well afford to make the contribution. Even with that, the contribution which the male makes to procreation is incomparably less depleting for him than are the contributions which the female makes for her.
11. Will vital fluid flow with every sexual intercourse? ”

“ Yet the whole process of sexual reproduction undoubtedly has, as its origin and explanation, the fusion in the first cell of the new generation from which all the rest will arise, of the material of two distinct individuals. ”

“ The instances just surveyed, these extremes of the potentiality of procreation, are instructive in more ways than one. They are to be regarded as “excrescences” of reproduction, comparable to those “excrescences” of individual growth which we call “ornament,” for example. Individuals on whom this fertility has settled, so to speak, are the victims of the machinery of sex and reproduction. Their amazing powers of multiplication303 are not of their own seeking, they are inherent manifestations of variations of growth, uncontrollable save by the machinery of Natural Selection. ”

“ These phenomena are (1) parthenogenesis; (2) oviparous and viviparous reproduction; (3) the production of generations of individuals in which the sexes are very unequally represented, males being frequently entirely absent; (4) the production of individuals differing as to the acquirement of wings, some remaining entirely apterous, while others go on to the winged form; (5) the production of individuals of the same sex with different sexual organs, and distinctions in the very early (but not the earliest) stages of the formation of the individual ”

“ The term Reproduction has, no doubt, been applied, by different writers, to both these functions;—to the processes by which an organ when mutilated, is restored by the forces of the living body, and to the process by which a new generation of individuals is produced which may be considered as taking the place of the old generation, as these are gradually removed by death. ”

“ But when I maintain that the meaning of sexual reproduction is to render possible the transformation of the higher organisms by means of natural selection, such a statement is not equivalent to the assertion that sexual reproduction originally came into existence in order to achieve this end. ”

“ The mode of reproduction is by ova, which are sometimes vivified in the body of the parent, and not only do they give birth by ejection from the mouth of a numerous progeny, but actual divisions of the body may be made, and each division will acquire completeness. ”

“ The offspring will thus be the result of the unfolding of a bit of germ plasm which will be different from that from which either of its parents developed, and these differences will result in congenital variations. Sexual reproduction thus results in congenital variations; and if congenital variations are necessary for the evolution of the living machine—and we shall soon see reason for believing that they are—we find that sexual reproduction is a device adopted for bringing out such congenital variations. ”

“ We have observed that, according to naturalists, the earliest forms of life which appeared on the earth were androgynous or hermaphrodite, that the two elements necessary for reproduction were originally confined within one and the same individual within which were carried on all the functions of reproduction. Later, however, a division of labour arose, and these two original functions became detached, after which time the reproductive processes were carried on only through the commingling of elements prepared by, or developed within, two separate and distinct individuals. ”

“ They stand for the most important phenomenon in the living world. Without it there would be no plants and no animals, excepting a few very low forms of no importance, and of course no human beings.
Fecundation or fertilization is the process of union of the female germ cell with the male germ cell; speaking of animals, it is the process of union of the egg or ovum of the female with the spermatozoön of the male. When a successful union of these two cells takes place a new being is started. The process of fertilization or fecundation is also [83] known as impregnation and conception. ”

“ Having once originated, the sexual type of reproduction possessed a definite survival value which assured its continuation. Sex makes possible a crossing of strains, which evidently possesses some great advantage, since the few simple forms which have no such division of reproductive functions have undergone no great development and all the higher, more complicated animals are sexual. ”

“ Among men, Birth Control has now evolved from the unconscious and instinctive phase, and is now unfolding and manifesting on the plane of conscious and voluntary activity. The influence of deliberate intention and conscious design is now one of the important factors in the process. Here at this point we reach a totally new aspect of reproduction. In the past stages of evolution the original impetus toward reproduction has been checked and directed by Nature, working along instinctive and unconscious lines ”