From what has been said it may therefore be concluded that the two states, heat and menstruation, are analogous, and that the essential accompaniment of both is the maturation and extrusion of ova.
The two perfected germ-cells before fecundation are in a state of nuclear rest after the numerous mitotic changes that have taken place in the maturation of these cells.
In oogenesis and spermatogenesis the phases of "Reduction," wherein the ovum and spermatozoon get rid of half the chromosomes during the stages of maturation of these germ-cells, are somewhat similar for both sexes.
No guide, no teacher can divine the intimate need of each pupil, and the time of maturation necessary to each; but only leave the child free, and all this will be revealed to us under the guidance of nature.
But if this maturation takes place, we ought to ask ourselves: "What have we done to help it?
This fact might be arguable in relation to the internal maturation of the masses; but it is beyond question in its relation to the individual.
Now the method chosen by our children in following their natural development is "meditation," for in no other way would they be led to linger so long over each individual task, and so to derive a gradual internal maturation therefrom.
Each child occupies himself with each object chosen for as long as he wishes; and this desire corresponds to the needs of the intimate maturation of the spirit, a process which demands persevering and prolonged exercise.
He goes where his internal force of development and maturation lead him.
Slow growth and maturation rates of the avian constituents of these ecosystems and resultant long recovery periods (Ashmole 1971) further aggravate this situation.
Slow growth andmaturation rates of arctic species and resultant prolonged population recovery periods further aggravate this situation.
This is not attributable to his weight and clumsiness alone, but largely to the fatty degeneration of his testicles and their excretory ducts, which prevents the due formation and maturation of the semen.
The result is that the gametes (sperm and eggs) they respectively produce in maturation are not exactly alike as to chromosome composition.
This is called maturation, or the maturation division, and the new cells have only half the original number of chromosomes.
The following is a general statement of the usual time required for the maturation of fruits:-- Grasses and Grains 13 to 15 days.
In this respect the phenomena occurring in the pollen-grains of Phanerogams bear an astonishing resemblance to the maturation of the animal egg.
The first event of importance for embryonic development is the maturation of the egg, i.
I must assume that the phenomena of maturation in the parthenogenetic egg and in the sexual egg are precisely identical, and that in both, the ovogenetic nucleoplasm must in some way be removed before embryonic development can begin.
In such cases, of course, its maturation would not be accompanied by the expulsion of somatic nucleoplasm.
The phenomena exhibited in the maturation of the egg are 225 identical in parthenogenetic and sexual development 2.
During maturation the accumulation of carbon dioxide is due to the seed-coat becoming impermeable to it.
Maturation involves a cessation, or at least a retardation, of the growth of the embryo, and this is shown to be the result of the accumulation of carbon dioxide in the tissues, which acts as a mild anaesthetic.
This degree of maturation diminishes their mucilage, and developes alcohol and carbonic acid; in consequence of which the cyder suffers no injury.
After the maturation of the fruit, when their green colour has changed to a dark yellow, they are plucked, opened, their beans cleared of the marrowy substance, and spread out to dry in the air.
Its maturation does not take more than a year, and is accomplished sometimes in nine months.
The cherry usually employed in Switzerland and Germany is a kind of morello, which on maturation becomes black, and has a kernel very large in proportion to its pulp.
The organ which affords the indigo is confined entirely to the pellicle of the leaves, and exists in largest quantity at the commencement of maturation while the plant is in flower.
The cheeks and forehead during the process of maturationpresent a continuous puffy elevation of a pearly white colour.
The action of the heart and capillaries is hurried during the papular and vesicular stages; but becomes more equable while maturation is going on.
Parallel Between the Maturation of Sperm- and Egg-Cell.
This element remains undivided in one of the maturation divisions of the spermatocytes, in some forms in the first in others in the second, and passes entire to one pole of the spindle (Fig.
In the discussion of the maturation of germ-cells (Chap.
Diagram showing the parallel between maturation of the sperm-cell and maturation of the ovum.
In Maturationthe Number of Chromosomes Is Reduced by One-Half.
Before we can understand fully the significance of the changes which go on during maturation we shall have to know more about the conditions which prevail among the chromosomes of cells.
As in maturation of the sperm-cell there is a growth period in which ooegonia enlarge to become primary ooecytes (Fig.
As regards the behavior of the chromosomes the maturation of the ovum parallels that of the sperm-cell.
And since in maturation there is an actual segregation of the chromosomes into two sets, half going to one cell and half to its mate, a physical basis adequate to the necessities of the case is really at hand.
The maturation process proper, which consists typically of two rapidly succeeding divisions, is preceded by a marked growth in size of the individual cells.
In the maturation of the male gamete the germ-cell, now known as a spermatogonium, increases greatly in size to become a primary spermatocyte.
When imported again to the south of Europe it first preserved its faculty of accelerated maturation in spite of the shortness of the days (Schübeler).
The maturation and expulsion of the ovule are generally accompanied in women by a nervous phenomenon closely related to erection in man.
When a sperm cell after maturation comes into the neighbourhood of a germ cell, it penetrates into its substance, using the long flagellum, or tail-like process, with which it is equipped as an organ of locomotion.
One of the points which may be briefly touched on is the question how it comes that two germ cells, once having passed through their maturation divisions, cannot fuse and form a new being; nor can two sperm cells.
These divisions are called ‘maturation divisions,’ and until they are accomplished, fecundation is impossible.
But in the course of the two maturation divisions of the germ cell, that cell loses its centrosome, which seems to be absorbed into the protoplasmic substance of the cell when once its task is accomplished.
They are the processes which lead to that innermaturation which gives a deeper realization of cognitions and which results in bursts of spontaneous synthesis and abstraction.
The brilliant discoveries of Strasburger and Auerbach have caused the attention of a large number of biologists to be turned to the phenomena accompanying the division of nuclei and the maturation and impregnation of the ovum.
List of important recent Publications on theMaturation and Impregnation of the Ovum.
There is abundant evidence that at the time ofmaturation of the egg the germinal vesicle undergoes peculiar changes, which are, in part at least, of a retrogressive character.
In what may probably be regarded as a normal case the following series of events accompanies the maturation and impregnation of an egg:-- (1) Transportation of the germinal vesicle to the surface of the egg.
In another student, on the contrary, who ate a living Cysticercus of the Tænia mediocanellata, the tapeworm reached its maturation in fifty-four days and eliminated the two first proglottides.
At or near the time of the maturation of the ova, the parent worm, hitherto lodged within the body of some insect, buries itself in the soil.
According to Bavay, five days suffice under favorable circumstances for the complete maturation of the worm.
Maturation thus becomes a part of ontogeny itself; it is not with fertilisation that morphogenesis begins, there is a sort of ontogeny anterior to fertilisation.
Amphibia) the state ofmaturation or “super”-maturation determines the sex of the future organism (R.
But the egg must be in the first stages of maturation to the extent that the “nuclear membrane” must be already dissolved.
In accordance with the idea of the plant, each one perishes with the maturation of the fruit.
The old liber dies with every maturation of the fruit, because there the difference attains solution.
In the maturation of ordinary ova two polar bodies are formed, but in parthogenetic ova only one.
Some observations and considerations upon the maturation phenomena of the germ-cells.
As in all the beetles so far studied there is no rest stage between the two maturation divisions, but the late anaphase of the first mitosis passes over quickly into the second spindle.
The ordinary chromosomes assume the form of rings and crosses in the prophase of the first maturation mitosis (fig.
The spireme appears to go directly over by condensation and segmentation into the dumb-bell-shaped figures seen in the first maturation spindle (figs.
The heterotypic maturation mitosis in Amphibia and its general significance.
Conditions external to the chromosomes may determine in certain cases, such as Dinophilus, which sex character shall dominate in the growing oocyte, and maturation occur accordingly.
It may be possible that the sex character of the egg after maturation is always dominant in the fertilized egg, as appears to be the case in these insects (see scheme).
In this species the unequal pair is more often found at a different level from the other chromosomes in the early metaphase of the first maturation mitosis (fig.
An early prophase of the first maturation mitosis (fig.
There is however abundant evidence that at the time of maturation of the egg the germinal vesicle undergoes peculiar changes, which are, in part at least, of a retrogressive character.
Maturation of the ovum and formation of the polar bodies.
In what may probably be regarded as a normal case the following series of events accompanies the maturation and impregnation of an ovum:-- (1) Transportation of the germinal vesicle to the surface of the egg.
The nature of the changes which take place in the maturation of the ovum may perhaps be most conveniently displayed by following the history of a single ovum.
Maturation of the Ovum, and formation of the polar bodies, pp.
On the Phenomena accompanying the Maturationand Impregnation of the Ovum.
On the whole, it may be said that the Seri hair is luxuriant and vigorous beyond the aboriginal average, and that it, like various other somatic features, indicates a relatively late maturation in the life-history of the individual.
In the male at one of the two maturation divisions the X chromosome passes to one pole undivided (fig.
This evolution of nerve-force which accompanies the maturation of the ovule, is the immediate cause of the afflux of blood to the utero-ovarian vessels.
The ganglionic nervous excitement coincident with the maturation of the ovule and the congestion of the uterus, is easily communicated to the vaso-motor nerves of the latter organ.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "maturation" in a variety of sentences. We hope that you will now be able to make sentences using this word.
