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Hindu Achievements in Exact Science: A Study in the History of Scientific Development c21: XV. Embryology

Hindu Achievements in Exact Science: A Study in the History of Scientific Development c21

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English

XV. Embryology

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IT is desirable at the outset to remember two facts in connection with modern embryology:

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1. It is only in recent years, thanks to the most magnifying microscopes, that the science has made real progress through the study of cells (" cytology ").

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2. Even Darwin believed that the children resemble their parents because the parents contribute multitudes of minute particles from their own tissues to form the cells of their offspring. But this theory of " pan-genesis " has been subsequently proved to be wrong.⁶⁷

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In the history of science Hindu embryologists deserve recognition (1) as having made precise observations, some of which are great approximations to the latest demonstrated truths, and (2) as having guessed at theories, some of which are eminently suggestive. As for pseudo-biological hypotheses, India has not been more prolific than Europe from Hippocrates to Buffon.²⁹

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Some of the facts observed and explained by Charaka and Sushruta are given below:

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(1) All the members of the human organism are formed at the same time, but are extremely small, as the first sprig of the bamboo contains the leaves, etc., of the future plant.⁷⁹ This idea of the development of the fertilized ovum by "palingenesis" survived in India after a long struggle with rival theories. It is an established truth to-day that though we find cells of one type in glands, of another type in the brain, of another type in the blood, and so forth, nevertheless all of them sprang from one original single cell.⁶⁷

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(2) "The hard substances of the fœtus, as hairs, bones, nails, teeth, vessels, ligaments, etc., are produced from the semen, and resemble the same part as in the father; and the soft parts as flesh, blood, fat, marrow, heart, navel, liver, spleen, intestines, etc., are formed principally from the blood of the mother, and resemble her."⁷⁹ This is virtually the Darwinian pangenesis now exploded.

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(3) Weisman's theory of "germinal continuity" is the greatest discovery of modern embryology. It is now held that "somatic" cells contribute absolutely nothing to the original germ-plasm, that no parent ever produces a germ cell, that the individual inherits nothing from his parents, but both he and they obtain their characteristics from a common source, and that the line of descent or inheritance is from germ-cell to germ-cell, not from parents.⁶⁷ This recent idea about the physical basis of inheritance brings out the distinction between germ-cells and body-cells (somatic). It was guessed to a certain extent by the Hindu biologists also in their controversy regarding the transmission of congenital deformities and constitutional diseases of parents to offspring.

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Atreya held that “ the parental seed (germ-plasm) contains the whole parental organism in miniature (or *in potentia*), but it is independent of the parents’ developed organs, and is not necessarily affected by their idosyncrasies or deformities.” The germ-plasm was described as an organic whole independent of the developed parental body and its organs. The physiological characters and predispositions of the offspring were explained as being determined by the constituent elements of this parental seed. The continued identity of the germ-plasm from generation to generation may be taken as a corollary to this, though nowhere expressly stated.⁵⁹

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(4) Elementary facts about impregnation, the cycle of sex, menopause, etc., could not but be observed:

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(*i*) The menses continue for seventeen days during which the woman may be impregnated, and not at any other season. This Hindu idea of absolute sterility after a certain number of days is still held by some modern physiologists, though not a demonstrated truth.

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(*ii*) The menses remain till the fiftieth year, when the woman is of a weak constitution; but it continues longer when the individual is strong.

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(5) Modern physiology would not reject the little kernel of truth that there is in the following statement: “The menses, after conception, goes in part to form the placenta, and as the blood flows every month, it coagulates to form the embryo; an upper layer being added every month to the embryo; and another portion to the breasts, of the mother, by which the mammæ are increased in size.”⁷⁹

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(6) The stages of fœtal development described on the basis of post-mortem operations and major operations in obstetric surgery had also much of the truth that has been established in recent years.

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“In the first month the mixture of the semen and menses forms a small mass like a pea; seven days after conception, it has the form of a bubble or inflated bag. On the tenth it is red, and on the fifteenth it resembles a small round piece of flesh. At one month it has small fibres proceeding from it and is animated with life.”⁷⁹

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One need not try to compare with this account the advanced and definite ideas of modern embryology about the development of the successive generations of cells, from the original fertilized ovum, e.g., “morula,” “blastocyst,” “yolk sac,” “entoderm,” “ectoderm,” “mesoderm,” etc. But the following may be accepted for “popular” purposes:

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In the third month five eminences appear, which when developed become the hands, feet and head. In the sixth month all the members of the body are formed, etc.⁷⁹

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(7) The following observation about the development of the rudimentary organs of reproduction contains a suggestive hint:

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The fœtus for a time remains indeterminate, and then takes on a definite male or female character. In the second month the sexual character is indicated by the shape of the fœtus, the shape of a round joint (?) indicating the male sex, and the elongated shape, as of a muscle (?), the female sex.⁵⁹

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(8) What determines sex? Can sex be produced at will? These questions have engaged the attention of scientists as well as quacks all through the ages both in the East and the West. The following Hindu ideas have had their European duplicates:

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(*i*) When conception occurs on the unequal days of menses, a female child will be born.

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(*ii*) Should the germ have more of the qualities of the semen, a male child will be formed, and of the menses, a female child.⁷⁹

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(*iii*) Before the fœtus takes on a definite male or female character, the development of the sex may be modified to some extent by food and drugs.⁵⁹

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Modern scientists have advanced several theories about sex-determinants.¹⁷ The truth remains yet to be discovered.

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