The sexual life of woman in its physiological, pathological and hygienic aspects

by E. Heinrich Kisch

Passing now to consider investigations made by physiologists, Born, at the anatomical institute at Breslau, has endeavoured to solve the problem of the determination of sex by means of experiment. He employed for this purpose rana fusca, an animal with which positive results can be obtained in a comparatively short period of time. He examined the sex both of the frogs in the free state (165), and also of larvæ which he had bred in specially arranged aquaria. Whereas among the frogs developing in the open, the numbers of the sexes appeared to be approximately equal (there was an excess of females amounting to 2 or 3 per cent.); among those bred in the aquaria there was an enormous preponderance of females (96 per cent.). This remarkable result is referred by Born to the inadequate supply of nutriment in the case of the larvæ bred by him (he fed them on hydræ and on putrefying frog and tadpole meat); from an examination of the alimentary canal of tadpoles caught in the open Born ascertained that their normal food was the mud of the pools in which they were hatched, containing infusoria, radiolariæ, diatoms, algæ, etc. The accuracy of this explanation appeared to Born to be more convincingly shown by the results in the case of one of his twenty-one aquaria. In this one alone the percentage of males was as high as 28 per cent., and the tadpoles in this attained the same size as those developed under natural conditions in the open, whilst in all the other aquaria the tadpoles remained abnormally small. This particular aquarium, owing to an oversight, had pond-mud on its floor, whilst all the other aquaria were floored with clean sand.

A. von Griesheim disputes Born’s results and believes that the latter, determining the sex of the tadpoles by means of a hand lens, must have mistaken a great many female tadpoles for males. He himself, by repeated enumerations of a large number of tadpoles (685), part caught in the open and part taken from a large aquarium, found that the ratio between the sexes in the case of rana fusca was regularly 36.7 males to 63.3 per cent. females.

E. Pflüger refers the divergence between Born’s results and his own and those of von Griesheim not to any error made by Born in the diagnosis of the sex of the tadpoles, but to the fact that in the latter’s aquaria the mortality of the male tadpoles was probably greater than that of the females. Pflüger endeavoured to ascertain whether the concentration of the semen might have an influence in the determination of sex. A quantity of frog-spawn was fertilized with concentrated semen, taken direct from the seminal vesicles, and another quantity of spawn was fertilized with diluted semen, obtained by making an aqueous extract of the incised testicles. The ratio between the sexes in the case of the two lots of tadpoles, which were kept in separate aquaria, proved, however, to be mathematically identical. But another experiment showed that the number of males was very different, according to the kind or race from which the animals were derived. He therefore believes that for the character of the development of the reproductive organs, the race of the parent animals is determinative. There is very little likelihood of being able to modify this inherited sexual ratio by means of outward influences affecting the ova and the ripe semen prior to fertilization, and just as little by means of a number of abnormal influences (change of climate, of water, of nutriment, etc.) acting on the fertilized ova.

Düsing,—who in his work on “The Regulation of the Sexual Ratio” (Jena, 1884) most ingeniously advocates the thesis that all animals have the power, when there is a lack of individuals of one sex, of procreating an excess of individuals of this deficient sex, or, to put it in another way, that an excess of one sex determines the procreation of an excess of the other sex,—instituted experimental investigations regarding the determination of sex in the following manner (in accordance with a suggestion made by Pflüger): About ninety guinea-pigs were distributed in two pens in such a way that in one pen there was a great deficiency of males and a great excess of females, whilst in the other there was a deficiency of females and an excess of males. Thus the sexual ratios in the two stalls were opposed. In accordance with Düsing’s theory, therefore, more males should have been born in the first pen and more females in the second pen. Every week each pen was examined once or twice, the sex of the new-born young was ascertained, and they were distinguished by small incisions in the margin of the ear. A week later, when the young animals had developed a little further, they were re-examined to make sure that no mistake had been made.

At first, in the pen containing the original excess of females, there occurred a quite remarkable excess of male births. This, however, was merely the result of chance, for soon the relationships of the sexes among the new born was reversed, and thenceforward many more females were born than males. But if all the births occurring in this experiment are taken into consideration the number is still far too small to allow trustworthy conclusions to be drawn.

Düsing emphasizes the fact that such an experiment as this, in order to furnish results worth consideration, must be continued until the sexual ratio has become constant, so that it is no longer subject to alteration by chance variations. If we assume that Düsing’s theory is false, the results obtained would be the following: In both the pens, in that in which there was originally an excess of females and in that in which there was originally an excess of males, the births, if observed through a sufficient period, would present a definite sexual ratio which would be the same in both the pens. But if the theory is well founded the sexual ratio of the new born would vary in the two pens: in the stall in which there had originally been a deficiency of males there would be an excess of births of males over females; whereas in the pen in which there had originally been a deficiency of females there would on the contrary be an excess of births of females over males. Düsing recommends that for such experiments even more fruitful animals, such as rats and mice, should be utilized.

Institutes for pisciculture would also be extremely suitable for such experiments in breeding for the determination of the matter under discussion because, owing to the fact that in these animals fertilization is effected outside of the body of the parents, a direct examination of the ova and the semen used in the experiments can be undertaken, and the fertilization can be made to occur under conditions subjected to various alterations; also we can employ the roe and the sperm of fishes whose age, life history, weight and size are accurately known.

Much attention has recently been paid to the theory of Schenk, based, as he states, upon numerous experiments regarding the influences by which sex is determined. This observer also starts from the principle that ovulation is not independent of the influences of nutrition and metabolism. He believes that in the cases in which combustion in the body is effected in such a manner that remnants of unconsumed substances, still capable of heat-production, make their appearance in the urine, the ovum of the human female in process of formation is not so far advanced in its development as it is in cases in which the urine is entirely free from sugar, or at any rate is free from any demonstrable traces of the presence of this body. In the former case we shall find that the ovum is not only less mature, but also that it is presumably less well nourished. In his view such an ovum is less completely endowed in respect of the indwelling qualities and forces of its protoplasm, and it appears for this reason to be adapted only for the development of a female individual. But when, on the contrary, in the maternal individual, all the substances formed in and assimilated by the organism have undergone combustion so completely that there is no sugar in the urine, not even in the minutest discernible traces, the maternal body is in a condition suitable for the development of an ovum adapted to become a male individual. From these inferences, weak though the chain of argument is, Schenk draws the conclusion, that by the regulation of the nutritive material supplied to the organism, and by the suitable choice of that material, we are to a considerable extent enabled to support an ovum in its process of maturation in such a manner as to cause it to develop into a male individual.

The nutritive material selected for this purpose must be of such a nature that the elimination in the urine of even the minutest quantities of sugar may be prevented; the urine must appear free from sugar even when the phenyl-hydrazine test is employed. Thus in every case in which we wish to influence a woman’s nutrition in such a way as to lead to the procreation of a male individual we must above all ascertain whether, in the woman in question, the normal quantity of sugar is present in the urine. If after the most careful examination no trace of sugar can be found in the urine, and if reducing substances are present in this excretion in abundance, no change need be made in the diet, and all we have to do is to recommend that the requisite fertilization should be effected as soon as possible, since there is every probability that in this condition the embryo will prove to be of the male sex. But when, on the other hand the “normal” quantity of sugar is present in the urine, or when even traces only of that substance can be detected, it is necessary by changes in the diet to cause the disappearance from the urine of every trace of sugar, and at the same time to bring about the appearance in that fluid of an abundance of reducing substances. Schenk claims by the experiments he has made along these lines to have obtained results which show that it is possible in this way to influence the determination of sex.

His method is to nourish the mother mainly on nitrogenous materials and fat, and to give in addition only so much carbohydrate as is necessary to prevent the absence of this from being seriously felt. This diet should be continued for a considerable period, at best for two or three months before the fertilization is effected. After conception also, the same diet should be continued. In such a manner we are able in certain cases to bring about the procreation of male offspring. On the other hand, the desire for the procreation of female offspring remains one which as yet we have no direct means of fulfilling.