When we pass from vegetal organisms to unconscious animal organisms, we see a like connection between proclivity and advantage. On observing how the tentacles of a polype attach themselves to, and begin to close round, a living creature, or some animal substance, while they are indifferent to the touch of other substance, we are similarly shown that diffusion of some of the nutritive juices into the tentacles, which is an incipient assimilation, causes the motions effecting prehension. And it is obvious that life would cease were these relations reversed. Nor is it otherwise with this fundamental connection between contact with food and taking in of food, among conscious creatures, up to the very highest. Tasting a substance implies the passage of its molecules through the mucous membrane of the tongue and palate; and this absorption, when it occurs with a substance serving for food, is but a commencement of the absorption carried on throughout the alimentary canal. Moreover, the sensation accompanying this absorption, when it is of the kind produced by food, initiates at the place where it is strongest, in front of the pharynx, an automatic act of swallowing, in a manner rudely analogous to that in which the stimulus of absorption in a polype's tentacles initiates prehension. If from these processes and relations that imply contact between a creature's surface and the substance it takes in, we turn to those set up by diffused particles of the substance, constituting to conscious creatures its odor, we meet a kindred general truth. Just as, after contact, some molecules of a mass of food are absorbed by the part touched, and excite the act of prehension, so are absorbed such of its molecules as, spreading through the water, reach the organism; and, being absorbed by it, excite those actions by which contact with the mass is effected. If the physical stimulation caused by the dispersed particles is not accompanied by consciousness, still the motor changes set up must conduce to survival of the organism, if they are such as end in contact; and there must be relative innutrition and mortality of organisms in which the produced contractions do not bring about this result. Nor can it be questioned that whenever and wherever the physical stimulation has a concomitant sentiency, this must be such as consists with, and conduces to, movement toward the nutritive matter: it must be not a repulsive but an attractive sentiency. And this which holds with the lowest consciousness, must hold throughout; as we see it do in all such superior creatures as are drawn to their food by odor.