Granted that man is only a more highly developed animal; that the ring-tailed monkey is a distant relative who has gradually developed acrobatic tendencies, and the hump-backed whale a far-off connection who in early life took to the sea—granted that back of these he is kin to the vegetable, and is still subject to the same laws as plants, fishes, birds, and beasts. Yet there is still this difference between man and all other animals—he is the only animal whose desires increase as they are fed; the only animal that is never satisfied. The wants of every other living thing are uniform and fixed. The ox of to-day aspires to no more than did the ox when man first yoked him. The sea gull of the English Channel, who poises himself above the swift steamer, wants no better food or lodging than the gulls who circled round as the keels of Cæsar’s galleys first grated on a British beach. Of all that nature offers them, be it ever so abundant, all living things save man can take, and care for, only enough to supply wants which are definite and fixed. The only use they can make of additional supplies or additional opportunities is to multiply. But not so with man. No sooner are his animal wants satisfied than new wants arise. Food he wants first, as does the beast; shelter next, as does the beast; and these given, his reproductive instincts assert their sway, as do those of the beast. But here man and beast part company. The beast never goes further; the man has but set his feet on the first step of an infinite progression—a progression upon which the beast never enters; a progression away from and above the beast. The demand for quantity once satisfied, he seeks quality. The very desires that he has in common with the beast become extended, refined, exalted. It is not merely hunger, but taste, that seeks gratification in food; in clothes, he seeks not merely comfort, but adornment; the rude shelter becomes a house; the undiscriminating sexual attraction begins to transmute itself into subtile influences, and the hard and common stock of animal life to blossom and to bloom into shapes of delicate beauty. As power to gratify his wants increases, so does aspiration grow. Held down to lower levels of desire, Lucullus will sup with Lucullus; twelve boars turn on spits that Antony’s mouthful of meat maybe done to a turn; every kingdom of Nature be ransacked to add to Cleopatra’s charms, and marble colonnades and hanging gardens and pyramids that rival the hills arise. Passing into higher forms of desire, that which slumbered in the plant and fitfully stirred in the beast, awakes in the man. The eyes of the mind are opened, and he longs to know. He braves the scorching heat of the desert and the icy blasts of the polar sea, but not for food; he watches all night, but it is to trace the circling of the eternal stars. He adds toil to toil, to gratify a hunger no animal has felt; to assuage a thirst no beast can know.