Hans Castorp lent an ear to the learned strife between ovists and animalculists: the first of whom asserted that the egg was in itself the complete little frog, dog, or human being, the male element being only the incitement to its growth; while the second saw in a spermatozoon, possessing head, arms, and legs, the perfected form of life shadowed forth, to which the egg performed only the office of “nourisher in life’s feast.” In the end they agreed to concede equal meritoriousness to ovum and semen, both of which, after all, sprang from originally indistinguishable procreative cells. He saw the single-celled organism of the fructified egg on the point of being transformed into a multiple-celled organism, by striation and division; saw the cell-bodies attach themselves to the lamellae of the mucous membrane; saw the germinal vesicle, the blastula, close itself in to form a cup or basin-shaped cavity, and begin the functions of receiving and digesting food. That was the gastrula, the protozoon, primeval form of all animal life, primeval form of flesh-borne beauty. Its two epithelia, the outer and the inner, the ectoderm and the entoderm, proved to be primitive organs out of whose foldings-in and -out, were developed the glands, the tissues, the sensory organs, the body processes.