Ovum

“ Ovum pene-solidum; placenta sarcomatosa cum tuberculis hœmatosis; involucra fœtûs solidificata. (Gestation four months and a half?)
What havoc has disease effected in this Ovum! Scarcely can we recognize a single element of its structure. The placental covering is composed of many substances, has lost its spongy vascularity—it has acquired several solid tumours, and is altogether unfit for its intended function. The cortex of the Ovum is fleshy; but within it a supernumerary fine membrane is seen, which might, but must not, be mistaken for the chorion. ”

“ If an ovum starts from the ovary and is not hindered, it will pass on through the uterus and the vagina into the world, and that is the end of it; but if, when the ovum starts from the ovary to make its way through the tube, the spermatozoa are deposited here at the mouth of the uterus, they will find their way up into the cavity, and if one meets an ovum and enters into it, a new life is begun. The ovum will now fasten itself to the walls of the uterus and grow into the little child. ”

“ That all life, even human, starts as a tiny ovum. That these tiny ova are produced in every female by a special tissue called the ovary, which develops at maturity when the eggs begin to ripen; that if the ova are not fertilized they do not develop; if they are fertilized they develop into an individual like the parent, though having personal peculiarities of its own. The fertilizing cells are produced in every male from a special tissue, which greatly develops at maturity when the fertilizing cells are matured and are capable of uniting with the ovum to produce the new being. ”

“ I told you of the germ or ovum that is produced by the ovary of the woman. That ovum of itself could never become a new being. It must be united with a life-giving principle furnished by the man. This principle consists of a fluid in which float tiny little creatures called spermatozoa—one is a spermatozoon. Here is a picture of some. They are too small to be seen without the aid of a microscope. ”

“ When mature, the ovum is contained in a membrane or chorion with a micropyle, and escapes by dehiscence of the follicle into the genital coelom and duct. In its passage to the exterior the ovum passes a glandular structure on the wall of the genital capsule, which probably secretes the gelatinous substance enclosing the eggs. In addition to this internal gland there are other accessory glands, which are not related to the genital duct or sac but are differentiations of the wall of the pallial cavity, and occur on the inner wall of the pallium in Nautilus, on the somatic wall in Dibranchiata. ”

“ The Ovaries, as already remarked, are two oval-shaped bodies, placed one on each side of the womb, and connected with it, whose use is to form the germ or rudiment, called the ovum, or egg, from which the new being is developed. The structure of the Ovaries is very simple, and the manner in which they produce the ovum is not very well understood. ”

“ That was the hen’s ovary. Ovum means an egg, and ovary means the place of the eggs.”
“O, mother, women don’t have eggs, do they? I don’t like that.”
“Well, if you do not like to use the word egg we can say ovum, which, you know, is the Latin word for egg. The plural is ova. Or we may call the ovum the germ, which means the primary source. The ovum or germ is a very tiny thing, so small that it cannot be seen without a microscope; 240 laid side by side would make only one inch in length.”
“O, mother, that is wonderful.”
“Yes, dear. The whole process of life is very wonderful and very beautiful. ”

“ The secreting or inner involucrum (amnion) of that Ovum, when laid open, was found tinged with blood and the cord distended by the same fluid which pervaded also the liquor amnii, as well as the fœtus itself. The morbid adhesions, contracted by the middle membrane with the chorion in consequence of plethora, are well marked in one part of the drawing by the artist to whom I carefully dissected the preparation. The chorion itself is in a morbid state.
Fig. 12. Ovum opacum plethoricum. (Eleven weeks after menstruation.) ”

“ Then they begin to develop and grow and push their way from the inside of the ovary to the surface where they look more or less like blisters. When an ovum reaches the surface of the ovary, a thin membrane which contains it, bursts, and it is suddenly expelled into the abdominal cavity. ”

“ After the ovum has reached the womb it remains there for a period of about ten days, after which, if it is not fertilized during that time, it passes out of the womb into the vaginal passage, and so out of the body. But if, at any time after it is ripe for fertilization, that is, from the time it begins its journey from the ovaries to the womb, and while it is in the womb, the ovum is met by the male sperm, it is liable to become fertilized—conception is possible. ”

“ Fig. 164. The human ova during early stages of development. (From Quain’s Anatomy.)
A. and B. Front and side view of an ovum figured by Reichert, supposed to be about thirteen days. e. embryonic area.
C. An ovum of about four or five weeks shewing the general structure of the ovum before the formation of the placenta. Part of the wall of the ovum is removed to shew the embryo in situ. (After Allen Thomson.)
The villi, which at first leave the flattened poles free, seem soon to extend first over one of the flat sides, and finally over the whole ovum (fig. 164 C) . ”

“ When the Ovum, after having lived and grown on its own life-principle, through its journey from the Ovarian nest into the cavity of the womb, has accomplished that connexion with the mother which before did not exist, the filiform vessels on the inner surface of the membrane in question, ought forthwith to begin to wither and be absorbed. ”

“ The exceptional forms are those in which the sperm of the male, making its way through the womb and Fallopian tubes, impregnates the ovum prior to its escape, and in which the now vitalized and growing ovum, by reason of its gradually increasing size, becomes imprisoned and fails to escape into the womb. ”

“ The formation of the polar bodies is independent of impregnation, and is the final act of the normal growth of the ovum. In a few types the polar cells are formed while the ovum is still in the ovary, as, for instance, in some species of Echini, Hydra, &c., but, according to our present knowledge, far more usually after the ovum has been laid. ”

“ Returning to the ovum which meets a spermatozoon in the course of its journey down the tube, we find that as soon as a spermatozoon enters an ovum it disappears and is completely absorbed, and, as the ovum in turn is instantly possessed of new powers, through the presence of the male cell, the result of this union is an entirely new cell. ”

“ The [87] ovum has no motion of its own, it is moved along by the wave-like motions of the lining cells of the Fallopian tube, and throughout the entire act it remains passive. The spermatozoön, on the other hand, is in a state of continuous activity from the moment it has been ejaculated by the male until it has reached its goal—the ovum. And as the spermatozoa carry in them the entire impress of the man, and the ova of the woman, they foretell us the fates of the future boy and girl. The woman's rôle throughout life is a passive and the man's an active one. ”

“ Ovulation, which probably occurs about midway between the menstrual periods, is simply the name which has been given to the principal function of the ovary and may be defined as the development of the ovum, or egg, and its expulsion, when mature, from the ovary. As the entire human 29body has its origin in this tiny ovum, its career and course of development are of momentous importance to us, and at the same time furnish a tale of absorbing interest. The ovaries are packed full of these tiny egg-like cells, which probably lie dormant, as stated before, until the girl reaches puberty. ”

“ In his view such an ovum is less completely endowed in respect of the indwelling qualities and forces of its protoplasm, and it appears for this reason to be adapted only for the development of a female individual. But when, on the contrary, in the maternal individual, all the substances formed in and assimilated by the organism have undergone combustion so completely that there is no sugar in the urine, not even in the minutest discernible traces, the maternal body is in a condition suitable for the development of an ovum adapted to become a male individual. ”

“ During embryological development the fertilized ovum—consisting of two fused fragments of this germinal substance—gives rise to a host of ordered and marshalled cells, which are divisible into two groups: the one forms the body with its muscles, bones, glands, digestive system, skin, sense-organs, nerve-centres, and so forth; the other forms a reserve store of germinal substance, from which are derived the ova and sperms. The former take no direct share in reproduction; they are off the line of continuous descent; they die without issue. ”

“ The yolk cells of the Amphibian ovum form a comparatively small mass, and are therefore rapidly enveloped; while in the case of the Elasmobranch ovum, owing to the greater mass of the yolk, the same process occupies a long period. In both ova the portion of the blastoderm, where epiblast and hypoblast become continuous, forms the dorsal lip of an opening—the anus of Rusconi—which leads into the alimentary cavity. This cavity has the same relation in both ova. It is lined dorsally by lower layer cells, and ventrally by yolk or what corresponds with yolk ”

“ When it reaches the womb, if there is no ovum present, it may remain there for a period of days awaiting its arrival, or may find its way into one of the Fallopian tubes which lead out to the ovary, and even go in quest of the object of its search as far as the ovary itself. ”

“ Between these is a gelatinous substance, and within the amnion is a fluid, called the liquor amnii. The two membranes, the liquor amnii, and the inclosed ovum, are called the ovulum! Immediately after conception the uterus begins to secrete, from its inner walls, another membrane, very delicate, called the decidua. This lines the whole cavity, so that when the ovulum passes out of the tube it is met by this lining which seems to prevent its entrance into the womb. The ovulum, however, presses upon it and so makes a depression, like a nest, in which it lies. ”

“ Among the conditions which, although the maturation of the ovum proceeds normally to a conclusion, may prevent conjugation between the male and female elements, we must in the first place consider an abnormal condition of the tunica albuginea of the ovary, a thickening of this membrane in consequence of inflammatory processes or of new formation of connective tissue, whereby the dehiscence of the follicle is rendered difficult or entirely prevented. ”

“ The fully developed zoösperms are suspended in a transparent, gelatinous fluid, which, mingled with the secretion of the prostate gland and other fluids which it meets during its expulsion from the body, constitutes the semen.
The Ovum.—The female element of generation, the ovum, is produced by an organ called the ovary, of which there are two in each individual. In size and form, the ovary closely resembles the testicle. Like the latter organ, also, it is formed within the body early in the process of development ”

“ The ovum from which this embryo takes its origin is visible long before the separate Salps of the chain have become completely developed. It is enveloped in a capsule continuous with a duct, which opens into the atrial cavity, and is usually spoken of as the oviduct. The capsule with the ovum is enveloped in a maternal blood sinus. Embryonic development commences after the chain has become broken up, and the spermatozoa derived from another individual would seem to be introduced to the ovum through the oviduct. ”

“ This yolk contains a germinal vesicle in which can be discovered a nucleus, called the germinal spot. The process of the growth of the ovaries is very gradual, and their function of ripening and discharging an ovum every month into the Fallopian tubes and uterus is not developed until between the twelfth and fifteenth years.
This period, which indicates, by the feelings and ideas, the desires and will, that the subjects are capable of procreation, is called puberty. ”

“ We are told that the cells of the segmented ovum may be disarranged to any extent by various means, such as raising the temperature, diluting the sea-water, removing the calcium from the sea-water, or by shaking, without prejudice to the ultimate normality of development. Each part of the ovum can therefore, according to the needs of the case, give rise to any part of the resulting organism. ”

“ True the ovum may measure as much as the one-hundred and fiftieth part of an inch, but the bulk of this is yolk-food necessary to furnish the tender germ with life and energy till it shall have attached itself to the walls of the womb, whence all its future nourishment is derived. ”

“ No mother ever embraced her newborn child more lovingly, or regarded it [Pg 227] with greater tenderness, than the womb receives the quickened ovum. When the ovum is quickened, every fibre of being thrills with a new purpose. A royal place is speedily prepared for the safety, nurture and development of the ovum. ”

“ At a certain stage in the segmentation the cells of the ovum become divided into two layers, an epiblast investing the whole of the ovum with the exception of a small area adjoining the placenta, where the inner layer or hypoblast, which forms the main mass of the ovum, projects at the surface. ”