tionists have expressed surprise that allied species will not cross, yet this should naturally be expected. As the body is developed by the soul, the soul can only produce its own form, and to do this a corresponding body must be provided. The inability to cross species is due to the initial body in the ovum being so different in its structure as to prevent Correspondence with the initial soul. The instances of varieties crossing is explicable upon the basis of the similarity of degrees in the germinal soul and in the germinal body, and a sufficiently close likeness in general form and nature.
In the case of the production of hybrids, the body from the mother is sufficiently akin to the soul from the father for the purpose of conception, but sterility in hybrids ensues because the body from the mother is not sufficiently in Correspondence with the soul from the father for the full operation of the functions of the soul in the body essential to procreation. The function of reproduction, which has its commencement in the finest substances of the soul, is dependent upon the highest organism of the body, and though the bodily organism of hybrids is able to perform in general the functions of the soul, the dissimilarity is fatal to the effective operation of the more highly organized and delicate function of procreation.
