have gone on developing side by side; each plant surviving in proportion as its seeds grew more and more distinctive, and each animal, in turn, standing a better chance of food in proportion as its discrimination of such seeds grew more and more acute. But as there are excellent reasons for crediting fishes and reptiles also with a high faculty for the perception of color, it may be safer to conclude that the sense was inherited by birds and mammals from our common vertebrate progenitors, being only quickened and intensified by the reactive influence of fruits.
Yet it must be remembered that the earliest fruit-eaters, though they might find the scarlet, crimson, or purple coats of their food an aid to discrimination in the primeval forests, would not necessarily derive any pleasure from the stimulation thus afforded That pleasure has been slowly begotten in all frugivorous races by the constant use of these particular nerves in the search for food, which has at last produced in them a calibre and a sensitiveness answering pleasurably to the appropriate stimulation. Just as the peach, which a dog would reject, has become delicious to our sense of taste; just as the pineapple, at which he would sniff unconcernedly, has become exquisite to our sense of smell—so the pure tints of the plum, the orange, the mango, and the pomegranate, which he would disregard, have become lovely to our sense of color. And, further still, just as we transfer the tastes formed in the first two cases to the sweetmeats of the East, or to the violets, hyacinths, and heliotropes of our gardens, so do we transfer the taste formed in the third case to our gorgeous peonies, roses, dahlias, crocuses, tiger-lilies, and chrysanthemums; to our silks, satins, damasks, and textile fabrics generally; to our vases, our mosaics, our painted windows, our frescoed walls, our Academies, our Louvres, and our Vaticans. Even as we put sugar and spices into insipid dishes to gratify the gustatory nerves, whose sensibility was originally developed by the savor of tropical fruits, so do we put red, blue, and purple, into our pottery, our decoration, and our painting, to gratify the visual nerves, whose sensibility was originally developed by the rich tint of grapes and strawberries, star-apples and oranges.
And here again, as in the case of flowers, the feeling once aroused has found for itself new objects in the voluntary selection of beautiful mates—that is to say, of mates whose coloring gratified the rising delight in pure tints. The taste formed upon blossoms produced, by its reaction, crimson butterflies and burnished beetles, the sun-birds of the East, and the humming-birds of the West. So, too, the taste formed upon fruits produced, by a like reaction, parrots, cockatoos, toucans, birds-of-paradise, nutmeg-pigeons, and a thousand other tropical creatures of exquisite plumage and delicate form. As we mount up through the mammalian series, we scarcely come upon any hues brighter than dull-brown or tawny-yellow among the marsupials, the carnivores, the ruminants, or the thick-skinned beasts; but when we arrive at the
