A publication appeared in the year 1786 dealing with the above-mentioned theory, and at the time attracted much attention. It has now become difficult to procure, and is often mentioned on account of its containing much that is valuable for influencing sex, both amongst men and animals, that has been gathered from all the authors of the previous century, and more especially from all the ancient authors who had written on this subject.
The author was J. Ch. Hencke, organist at Hildesheim, and the title of his book, ‘The Secret of Nature Completely Discovered, both in the Procreation of Man, and for the absolute choice of the Sex of Children.’ Brunswick, 1786. (Völlig entdecktes Geheimniss der Natur, sowohl in der Erzeugung des Menschen als auch in der willkürlichen Wahl des Geschlechts der Kinder. Braunschweig, 1786.) The author relies upon exploded theories, according to which the offspring is evolved, as it were, out of a mixture of the generative secretions of the two sexes, and can be induced to develop into either a male or female individual. Thus the sex is not previously determined, only in the course of its development out of the developing mass, which consists of a mixture of male and female generative secretions, distinctive sexual characteristics make their appearance, according to the predominance of the male or female portion of the mixture. But here, also, the old theory is set forth very precisely. The generative matter of the right testicle serves to fructify ova from which males are developed, that of the left testicle is used to fructify and develop female ova. Similarly, the tenet is propounded that the right ovary contains male ova and the left such only as will, when developed, produce female offspring.
These doctrines, as a basis for the breeding of animals, Hencke had discovered by castrating swine, dogs, and rabbits. Thus it happened that a boar, who, after castration, had only the left testicle, twice running bred with a sow female young only. Similar phenomena occurred with other animals, so that this method was recommended by the author to the breeders of his time. But it happened, also, that a surgeon upon opening the body of a woman who had had sons only and never a single daughter, found the left ovary very thin and withered, so that it was hardly possible that it could serve for the development of a new individual. On the contrary, the right ovary was in a normal condition. It now remained only to discover some device for man, by which he might be able, during the act of generation, to avail himself of the discoveries thus made, so as to obtain the result of an absolute choice of the sex of the offspring. The ligation of one of the testicles was Hencke’s infallible remedy. When this severe proceeding proved impracticable, in its place was substituted an elevation of the testicle by means of its suspending muscle (the cremaster). Under certain conditions this takes place of itself in particular positions, and was accordingly recommended as an established proceeding for men.
One other conclusion of Hencke’s deserves particular mention. He was bold enough not only to assert that the right and left sexual glands served exclusively for the generation of male and female individuals, respectively, but also asserted that the generative matter from the right or left gland of one parent was productive only when united with that of the same gland of the other parent. His counsels were not for such persons as are too heated, too ardent. “For young, hot, hasty men,” he says, “who are altogether without consideration, I am not writing; but for chaste married people, and especially for those to whom the production of a child of one or the other sex is a matter of importance.”
Couteau established the fact that each seminal duct had its own orifice, through which the semen was poured into the urethra. This fact was in his days of the greatest importance, as it prevented any mixture of the semen of a man’s two testicles. Hencke firmly insisted that the semen was discharged by one testicle or seminal vesicle alone, in the case when the testicle was raised up. But we need not here follow further Hencke’s theories which he deduced from his own experiments. In the present day these theories will satisfy no one. Results which have been obtained either after ovariotomy, or after the extirpation of testicles, have made us perfectly certain about the value of one or the other generative gland for the production of the male or female sex. The case of Schatz, which has been also pointed to us as important in other specialist works, may not be uninteresting here. The left ovary of a young girl was removed, together with a portion of the left tube, and the right ovary, also, with the exception of a margin of about two millimetres’ breadth. When she was married she gave birth to a girl, whereas a boy should have been expected, seeing that only male offspring were to be produced by the right ovary.
Scarcely any work that lies before us on this subject is so much regarded as that of Hencke. At the same time, and although it had in its day the widest circulation, it frequently met with the most unqualified condemnation. Dr. von Seligson, in his discourse before the Society of Medical Practitioners at Moscow (1895), on the subject of influencing the development of sex, in connection with Hencke’s theory, attached value to a great number of experiments tending to support the old view. It was, however, admitted that by a departure of nature from the ordinary law (somewhat resembling a transposition of the viscera) male or female ova might occur in the respectively opposite ovaries.