=Origin of Beauty=.--For example, it has been urged that natural selection can only account for _useful_ structures; but _beauty_ is as universal and as conspicuous in nature as _use_. In many cases Darwin has shown that beauty is useful, and in such cases it is, of course, seized upon by selection and intensified. Thus, the gorgeous coloring of birds and insects is largely due to sexual selection. Beauty is attractive, and therefore the most beautiful prevail in securing reproductive opportunities. This character is, therefore, perpetuated in the offspring, and intensified from generation to generation. But, of course, this can apply only to higher animals, in which the sexes are separate and sexual union voluntary. It can not apply to self-fertilizing hermaphrodites; and yet in these, also, we often find the most gorgeous coloring. Again, Darwin has very ingeniously and successfully explained the case of the beauty and fragrance of flowers of hermaphroditic plants by another principle, viz., that of _insect-selection_. Insects are attracted by the most showy and fragrant flowers, and thus become the means of carrying pollen from flower to flower, insuring fertilization, and especially cross-fertilization. The most beautiful and fragrant flowers are most certain to be fertilized, and thus beauty and fragrance become useful to the plant, and therefore are selected and intensified. These and many other cases of beauty may doubtless be explained by showing that it is useful; but beauty which is without any use can not be explained by natural selection. Now, as already said, the most gorgeous beauty is lavishly distributed even among the lowest animals, such as marine shells and polyps, where no such explanation is possible. The process by which such beauty is originated and intensified is wholly unknown to us.