(_a_) The individual _animal_ is, for example, fettered wholly within the bounds of its natural environment of air, water and land. Its entire way of living, the mode of its self-nourishment, everything that concerns it, is thereby determined. It is this which differentiates with such variety the species of animal life. We find, moreover, intermediate strains, such as swimming birds and suckling animals, which live in the water, amphibious species and others which still further mediate between the more obviously generic. These are, however, mere confusions of race, and indicate no higher mediation of considerable range. Throughout we find the animal subject in its self-preservation to the absolute necessities of external nature, cold, drought, or insufficient supply of the means of nourishment. Under this despotic dominion it is liable through the parsimony of circumstance to lose the fulness of external form, the blossom of its beauty, in short to become as it were the reflex of starving Nature herself. External conditions fix imperatively the measure of beauty it either preserves or forfeits.
(_b_) The human organism, in its particular bodily existence is subject, if not in the same measure, to external forces of Nature, and is compelled to face the same contingencies, deficient livelihoods, and every kind of harassing disease and misery.