The Drama of Love and Death: A Study of Human Evolution and Transfiguration. Edward Carpenter

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СКАЧАТЬ which it is said that there are always a definite and invariable number for every species of plant or animal,^[6] and which are now generally supposed to contain the hereditary elements or determinants of the future individual—these chromosomes have already arranged themselves longitudinally and end-on to each other across the middle of the cell. They now, apparently under the influence of the radiating points at each pole, split longitudinally (as one splits a log of wood)—so that each chromosome, dividing throughout its length, contributes one half of itself to one pole and one half to the other. The halves so formed separate, and approach their respective poles; and at the same time the cell-wall constricting itself along the equatorial line, or line of separation, soon divides the original cell into two. Meanwhile the chromosomes in each new division group themselves (not round but) near their respective poles or centrosomes, and a new nucleus membrane forming, encloses each group, so that finally we have two cells of exactly the same constitution as the original one, and with exactly the same number and quality of chromosomes as the original.^[7]

      The whole process seems very strange and wonderful. No military evolutions and formations, no complex and mystic dance of initiates in a temple, with advances and retreats, and combinations and separations, and exchanges of partners, could seem more fraught with intelligence.^[8] Yet this is what takes place among some of the very lowest forms of life, on the division of a single cell into two. And it is exactly the same, apparently, which takes place in the higher forms of life when the single cell which is the result of the fusion together of the sperm-cell and the germ-cell, divides and subdivides to form the ‘body’ of the creature. As is well known, the joint cell divides first into two; then each of the cells so formed divides into two, making four in all; then each of these divides into two, making eight; then each into two again, making 16, 32, 64, and so on—till they number the thousands, hundreds of thousands, millions, which in effect build up and constitute the body. And at each division the process is carried out with this amazing care and exactness of partition described—so that every cell is verily continuous and of the same nature with the original cell, and contains the same nuclear elements, derived half from the father and half from the mother. Yet in the process a differentiation has set in, so that in the end each cell becomes so far modified as to be adapted for its special position and function in the body—for the skin, mucous membrane, blood corpuscles, brain, muscular tissue, and so forth.^[9] It is worth while looking carefully at the body of an animal, or one’s own body, in order to realize what this means—to realize that the entire creature, in all its form and feature, its coloring, marking, swiftness of limb, complexity of brain, and so on, has provably been exhaled from a single cell, is indeed that original cell with its latent powers and virtue made manifest; and to remember that that original cell was itself the fusion of two parent cells, the male and the female.

      A word, then, upon this matter of the fusion of the two parent cells in one. Here, again, two very remarkable things appear. One refers to the equality of the sexes; the other refers to the onesidedness (or deficiency or imperfection) which seems to be the characteristic and the motive power of the phenomenon of sex.

      With regard to the first point, we saw that among the Protozoa conjugation occurs for the most part between two individual cells which are alike in size and (to all appearance) alike in constitution; and this conjugation leads to reproduction. But when among the higher forms sex begins to show, the conjugating cells—sperm-cell and germ-cell—are generally unlike in size, and often in the higher animals extremely unlike—as in the human spermatozoon and ovum, of which the latter is a thousand times the volume of the former;^[10] and this has sometimes led, as remarked before, to an exaggerated view of the preponderant importance of one sex. But the curious fact seems to be that when the spermatozoon of the human or higher animal penetrates the ovum, there is a preliminary period before its nucleus actually combines with the nucleus of the ovum, during which the nucleus rapidly absorbs nourishment from the surrounding protoplasm, and grows—grows till it becomes of exactly the same size as the nucleus of the ovum. The situation then is that there are two nuclei of the same size and both charged with chromatin of the same general character, in close proximity, and waiting to fuse with each other.

      The product of that fusion is a new being; and as far as can at present apparently be observed, the parts played by the two sexes in the process are quite equal. There may be difference of function but there is no inequality. “Both male and female cells,” says Professor Rolleston,^[11] “prepare themselves for conjugation long before it takes place, and neither of them can be said to be a more active agent in fertilization than the other. Not ‘fertilization’ but ‘fusion’ is the keyword of the process. The mystical conception, as old as Plato, of the male and female as representing respectively the two halves of a complete being, turns out to be no poetic metaphor. As regards the essential features of reproduction, it is a literal fact.”

      The second remarkable point has to do with the onesidedness of sexual conjugation, and the complementary nature of the exchange involved. This is truly noteworthy and interesting. It is evident that if the sperm-cell and germ-cell simply coalesced, containing each the amount of chromatin characteristic of the species—say sixteen chromosomes in the case of the human being—the result would be a cell with double the proper amount, say thirty-two chromosomes, i.e. an amount belonging to another species. “What happens is that each of the reproductive cells, male and female, prepares itself for conjugation by getting rid of half its chromosomes. Two divisions of the nucleus take place, not as in the ordinary fashion of cell-division, when the chromosomes split longitudinally, but in such a way that, in each division, four of the sixteen chromosomes (making eight in all) are bodily expelled from the nucleus and from the cell, when they either perish, or, in some cases, appear to help in forming an envelope of nutritive matter round the germ-cell. These divisions are called ‘maturation divisions,’ and until they are accomplished fecundation is impossible.”^[12] Thus the two nuclei, having each their number of chromosomes reduced to half the normal number (in this case to eight), are now ready to coalesce and so form a new cell with the proper number belonging to the species (i.e. sixteen). This cell is the commencement of the new being, and, as already described, it divides and re-divides, and the innumerable cells so formed differentiate themselves into different tissues, until the whole animal is built up.

      Says Professor E. B. Wilson:—“The one fact of maturation that stands out with perfect clearness and certainty amid all the controversies surrounding it, is a reduction of the number of chromosomes in the ultimate germ [and sperm] cells^[13] to one half the number characteristic of the somatic cells. It is equally clear that this reduction is a preparation of the germ [and sperm] cells for their subsequent union, and a means by which the number of chromosomes is held constant in the species.”^[14]

      This extrusion or expulsion by each of the conjugating cells of half its constituent elements is certainly very strange.^[15] And it seems strangely deliberate.^[16] Various theories have been formed on the subject, but at present there is apparently no satisfactory conclusion as to what exactly takes place. Some think that in the one case certain male elements are expelled, and in the other case certain female elements; and anyhow it seems probable that a complementary action sets in, by which each prepares itself to supply a different class of elements from the other, thus rendering the conjunction more effectual. Plato has been already quoted with regard to male and female being only the two halves of a complete original being. He also says (in the speech of Socrates in the Banquet) that the mother of Love was Poverty, and that Love “possesses thus far his mother’s nature that he is ever the companion of Want.” And it would appear that in the most primitive grades of life the same is true, and that two cells combine or coalesce in order to mutually supply some want or deficiency.

      Anyhow, in the process just described two points stand out pretty clear: first, the exact quality of the number of chromosomes contributed by sperm-cell and germ-cell to the fertilized ovum—which seems to indicate that the descendant being has an equal heredity from each parent^[17]—though of course it does not follow that both heredities СКАЧАТЬ