4. The beauty of form, proportion, and coloring that abounds in nature affords evidence of mind. Herculean efforts have been made by modern evolutionists to eliminate altogether the idea of beauty from nature, by theories of sexual selection and the like, and to persuade us that beauty is merely utility in disguise, and even then only an accidental coincidence between our perceptions and certain external things. But in no part of their argument have they more signally failed in accounting for the observed facts, and in no part have they more seriously outraged the common sense and natural taste of men. In point of fact, we have here one of those great correlations belonging to the unity of nature--that indissoluble connection which has been established between the senses and the æsthetic sentiments of man and certain things in the external world. But there is more in beauty than this merely anthropological relation. Certain forms, for example, adopted in the skeletons of the lower animals are necessarily beautiful because of their geometrical proportions. Certain styles of coloring are necessarily beautiful because of harmonies and contrasts which depend on the essential properties of the waves of light. Beauty is thus in a great measure independent of the taste of the spectator. It is also independent of mere utility, since, even if we admit that all these combinations of forms, motions, and colors which we call beautiful are also useful, it is easy to perceive that the end could often be attained without the beauty.
It is a curious fact that some of the simplest animals--as, for example, sponges and Foraminifera,--are furnished with the most beautiful skeletons. Nothing can exceed the beauty of form and proportions in the shells of some Foraminifera and Polycistina, or in the skeletons of some silicious sponges (see Fig. 19), while it is obvious that these humble creatures, without brains and external senses, can neither contrive nor appreciate the beauty with which they are clothed. Further, some of these structures are very old geologically. The sponge whose skeleton his known as "Venus's flower-basket" produces a structure of interwoven silicious threads exquisite in its beauty and perfect in its mechanical arrangements for strength (Figure 20). Even in the old Cambrian rocks there are remains of sponges which seem already to have practically solved the geometrical problems involved in the production of these wonderful skeletons; and with a Chinese-like persistency, having attained to perfection, they have adhered to it throughout geological time. Nor is there anything of mere inorganic crystallization in this. The silica of which the skeletons are made is colloidal, not crystalline, and the forms themselves have no relations to the crystalline axes of silica. Such illustrations might be multiplied to any extent, and apply to all the beauties of form, structure, and coloring which abound around us and far excel our artificial imitations of them.