In experiments of this kind metabolic activity will show itself in the organism, as it may be perceived from the nitrogenous constituents of the urine that a greater exchange of nutritive matter is taking place, a thing that happens also with normal individuals.
Under these circumstances the specific gravity of the urine is also increased, and it may sometimes become relatively considerable (1030 to 1035).
In consequence of the influence which the altered diet, if commenced a sufficiently long time before conception, exerts both over the mother and over the ovum which is being prepared for fertilization, it is possible that this ovum may develop itself into a male individual.
It also sometimes happens that, even with careful dieting, the conditions which are necessary for our purpose are not realized—viz.: that the sugar does not disappear from the urine, that the mother cannot accommodate herself to a diet of the kind required. She finds the situation intolerable, because she cannot do without an abundance of starchy substances and sugar, and in consequence all hope of a satisfactory result falls to the ground.
There are persons who from their youth upwards have lived principally on vegetable food, and are therefore not accustomed to take the nitrogenous substances of their diet in the concentrated form in which they are presented in the albuminous constituent of meat. They obtain the necessary nitrogen for the body from large amounts of food containing a great quantity of water, and it may happen that they cannot easily submit themselves to such a change of diet without pernicious consequences. To this class belong the women who live in the rural districts of many of the mountainous regions of central Europe, where little flesh is eaten. With them it might often be a difficult matter to make an abrupt change of diet of the desired kind. Such individuals can be reconciled to the kind of diet we recommend only by a gradual advance in the quantity of concentrated nitrogenous food. But in such cases it might very likely prove possible to attain our end by a corresponding vegetable diet.
The following case, which was conducted under my control with the greatest care, and was also a case of an intelligent woman, who showed the greatest willingness to do anything, in order that she might have male offspring, is of the highest interest for our theory.
This woman was of a family in which principally female children had been born. Although all its members were fruitful, no great number of descendants seemed to have been reached. It is not unlikely that the multiplication of descendants was restrained. The existence of a tendency to provide female ova for fertilization was also proved by testing the urine for sugar.
In the case of this woman, who wished to have male offspring, the examination of the urine each time showed, as with the other women of the family, traces of sugar. With her ordinary diet sugar was found in the urine (that of twenty-four hours being collected) in minute quantities. The unoxidized minute traces of sugar signified imperfect combustion.