There are minute animalcules belonging to the group of flagellate Infusoria, some of which, under ordinary microscopic powers, appear merely as moving specks, and show their actual structures only under powers of two thousand diameters, or more; yet these animals can be seen to have an outer skin and an inner mass, to have pulsating sacs and reproductive organs, and threadlike flagella wherewith to swim. Their eggs are, of course, much smaller than themselves—so much so that some of them are probably invisible under the highest powers yet employed. Each of them, however, is potentially an animal, with all its parts represented structurally in some way. Nor need we wonder at this. It has been calculated that a speck scarcely visible under the most powerful microscope may contain two million four hundred thousand molecules of protoplasm.[13] If each of these molecules were a brick, there would be enough of them to build a terrace of twenty-five good dwelling-houses. But this is supposing them to be all alike; whereas we know that the molecules of albumen are capable of being of very various kinds. Each of these molecules really contains eight hundred and eighty-two ultimate atoms—namely, four hundred of carbon, three hundred and ten of hydrogen, one hundred and twenty of oxygen, fifty of nitrogen, and two of sulphur and phosphorus. Now, we know that these atoms may be differently arranged in different molecules, producing considerable difference of properties. Let us try, then, to calculate of how many differences of arrangement the atoms of one molecule of protoplasm are susceptible, and then to calculate of how many changes these different assemblages are capable in a microscopic dot composed of two million four hundred thousand of them. It is scarcely necessary to say that such a calculation, in the multitudes of possibilities involved, transcends human powers of imagination; yet it answers questions of mechanical and chemical grouping merely, without any reference to the additional mystery of life. Let it be observed that this vastly complex material is assumed as if there were nothing remarkable in it, by many of those theorists who plausibly explain to us the spontaneous origin of living things. But nature, in arranging all the parts of a complicated animal beforehand in an apparently structureless microscopic ovum, has all these vast numbers to deal with in working out the exact result; and this not in one case merely, but in multitudes of cases involving the most varied combinations. We can scarcely suppose the atoms themselves to have the power of thus unerringly marshalling themselves to work out the structures of organisms infinitely varied, yet all alike after their kinds. If not, then "Nature" must be a goddess gifted with superhuman powers of calculation and marvellous deftness in arranging invisible atoms.
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.
Fig. 19.
Magnified portion of a silicious sponge, showing the principle of construction of the hexactinellid sponges, with six-rayed spicules joined together and strengthened with diagonal braces. (After Zittel.)
Fig. 20.
Euplectella, or "Venus's flower-basket," a silicious sponge, showing its general form. (Reduced, from Am. Naturalist, vol. iv.)
5. The instincts of the lower animals imply a Higher Intelligence. Instinct, in the theistic view of nature, can be nothing less than a divine inspiration placing the animal in relation with other things and processes, often of the most complex character, and which it could by no means have devised for itself. Further, instinct is in its very essence a thing unimprovable. Like the laws of nature, it operates invariably; and if diminished or changed, it would prove useless for its purpose. It is not, like human inventions, slowly perfected under the influence of thought and imagination, and laboriously taught by each generation to its successors: it is inherited by each generation in all its perfection, and from the first goes directly to its end as if it were a merely physical cause.