The periodical maturation and extrusion of ova, independently of coitus, in mammalia and man, proved to be the primary condition to their propagation / Translated from the German by Henry Smith.

  • Bischoff, Th. Ludw. Wilh. (Theodor Ludwig Wilhelm), 1807-1882
Date:
1845
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Licence: Public Domain Mark

Credit: The periodical maturation and extrusion of ova, independently of coitus, in mammalia and man, proved to be the primary condition to their propagation / Translated from the German by Henry Smith. Source: Wellcome Collection.

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    development. Should these circumstances not come into operation, or should an interruption develop itself in their course, the generative materials mature notwithstanding, and are separated, although no germs capable of development result from them. Examples of this in the vegetable kingdom, and in the lower classes of animals, as well as in fishes, amphibia, and birds, are too well known to require mention here. On the other hand, in reference to mammalia and man, the case stood quite different. With respect to them, the formation of a germ was quite universally regarded as the result of coition ; that act, in their case, being considered not only to have the design of rendering the female generative matter capable of development, but also of altogether producing it for the first time (creating it, erst hervorhringeri). This opinion was of course chiefly based upon ignorance of the existence of the female generative material, the ovum, previously to coition. So stood the matter, when, at length, after centuries of controversy. Von Baer, in 1827, discovered the ovarian ovum of mammalia and man, and at the same time, in its unexpected minuteness, the cause of its long concealment. I have always felt astonished that this discovery, in a department of science which has interested mankind in all ages in so extraordinary a degree, did not excite greater and more universal attention. By some it has been received, by some denied, taken no cognizance of by others; and only embryologists, in the strictest sense of the word, have occupied themselves with it, and they indeed only in its relation to the development of the embryo, and not with reference to the theory of generation in particular. This theory, which had so often been erected upon an hypothetical ovum, was so firmly based as even to suppress for a time the necessity for investigation as to how it might harmonize with what was founded on fact, after that very matter of fact became known. Although the existence of the ovum previous to, and independently of, all coition, was proved, yet coition was still held to be the sole and necessary condition to the maturation and extrusion of an ovum from the ovary; and all other circumstances, however distinctly they might indicate the contrary, were considered only from that point of view. I was myself so much influenced by this theory, as to be led blindly by it in the course of my previous researches on the development of mammalia. They were, it .is true, directed more particularly to the development of the fecundated ovum; but the process of fecundation was an essential object of them, and as I availed myself of the knowledge of the ovum I certainly succeeded in rectifying and throwing light upon several points which my predecessors had remained unacquainted with. Yet still I w'as always biassed by the opinion, that the passing out of the ovum from the ovary, the first condition therefore of its development, must have in some way or other a necessary relation to copulation. Like all who had preceded me,