2972. As the separation of the substances composing the ovum is an advancing-step towards their improvement, so also is the removal of the albumen-glands from the vitelline sac a nobler condition. They cannot, however, remove further off than to the thorax, because this is the highest post or station of the vegetative parts.
2973. Milk is a vegetable product of the animal.
2974. Numerous mammæ are a lower development.
2975. The milk is albumen, which has been secreted by tegumentary glands; it is animal albumen. The lacteal or milk-organs therefore belong to the sexual system.
2976. As the male parts are only the female otherwise developed, it is to be comprehended why the male animals also have mammæ. They are probably the embryo's principal organ of absorption.
Functions of the Uterus.
2977. Now, the uterus obtains the sexual food in a living state, and from its being such is affected by it.
2978. The uterus must be thus a world for the living germ. Two processes are, however, indispensable for the germ, namely nutrition and respiration; both of which are furnished by the uterus.
2979. The uterus is to be regarded as the water, the sea in which the germ or embryo is developed. The water decomposes into basic nutritive matter and oxygenous matter of respiration. The water of the uterus is the blood; this is separated through the antagonism of the fœtus into mucus and oxygen. The mucus penetrates into the amnion, the oxygen into the chorion, or the placenta.
2980. The fundus of the uterus is more arteriose than the os uteri, and stands therefore in opposition with it.