How Haeckel proceeds to argue that such appearance of purposive design is merely fallacious, we need not here stay to enquire; our present concern is to attempt to realize the evidence of law and order which the world everywhere exhibits. As we have just heard, the parts of an organism, like those of a motor-car, or a chronometer, combine their operations for the production of definite ends; the attainment of which depends in all instances upon the nicest correspondence of various details of their work. Thus, that there should be eyes capable of seeing, the laws of optics must be satisfied, reflection, refraction and the rest, just as exactly in the making of an eye as in that of a telescope. _De facto_ they _are_ satisfied. The eye, Mr. Darwin styles[128] "a living optical instrument as superior to one of glass as the works of the Creator[129] are to those of man." He speaks, moreover, of "all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration."[130] Therefore, however we are to account for them, the laws which govern the production of eyes successfully solve a practical problem and satisfy laws which were in force before an animal with eyes appeared on earth. In just the same way, the requirements of sound are met by the structure of the ear, which Sir Henry Holland, for example,[131] judged more wonderful than that of the eye itself. So again as to wings. They are in the first place such marvellous pieces of workmanship that as Mr. Pettigrew writes concerning one of their forms.[132] "There are few things in nature more admirably constructed than the wing of a bird, and perhaps none where design can be more readily traced." But, moreover, wings entirely different in plan, as of birds, bats, and all the varieties of insects, alike satisfy the laws of aerostatics, and successfully solve in practice the problem of flight, a problem which we are unable to solve even theoretically. "It is evident," writes Lord Grimthorpe,[133] "that nobody yet thoroughly understands the whole theory of flying, though we are seeing it continually, and have unlimited opportunities of examining all sorts of wings. The explanation that appears plausible for one kind, not only will not do for another but seems refuted by it." Yet in a multitude of different ways, the forces of Nature succeed in effecting what with all our Science we cannot shew to be possible. And concerning not merely one portion of a creature's structure, but the whole, Professor Huxley declares:[134]