It is an epoch of tremendous importance when the baby first, with real attention, brings sight and touch and muscle feeling to bear together on an object. “In a very deep sense,” says John Fiske, “all human science is but the increment of the power of the eye, and all human art is the increment of the power of the hand. Vision and manipulation--these in their countless indirect and transfigured forms are the two coöperating factors in all intellectual progress.” And the first great result of this coöperation is the completion of vision itself. It cannot be doubted that it is mainly by studying objects with eye and hand together that we get our ability to see solid form. A colt grasping his ear of corn with his teeth, even a puppy licking and turning his bone all over, or a kitten tapping a spool to and fro and hugging it in her paws, without losing sight of it--none of these can bring the united powers of three senses to bear on an object so perfectly as a monkey or human baby can, holding it in the most convenient positions, turning it this way and that, seeing every part, feeling it with finger tips and mouth; and it is doubtful if the quadrupeds ever attain to as clear a sense of form as we do. In these first days of the passion for grasping at things, the baby reached for flat figures as readily as for solid objects; but (to look ahead a little) she learned to discriminate with surprising ease, and after the first week I have only three or four notes of her trying to pick up such things as pictures on a page, roses on a quilt, shadows in the sun. Yet I do not think this was because she gained quickly any such sense of the difference between plane and solid form as we have, but rather that she learned quickly to associate a certain look about an object with the experience of being able to get hold of it. The reason that I think so is that even weeks later, when she was six months old, she showed signs of having no real ability to judge form by the eye. At that age she turned a round cracker round and round at her lips, trying to find the corner to bite, as she was used to doing with square ones. And the only time she was ever taken in by a flat figure afterward was when (at nine months old) she tried a long time to capture the swaying shadow of a rope end on the deck of a yacht; things that moved could always be taken hold of in her experience, and she went solely by experience, not by any general ideas of form. But such general ideas really require a good deal of development of reason--so much that it is likely the lower animals never rise to them. We must think of the baby’s seeing, therefore, as rounding out but slowly to full equality with ours in such matters as estimates of form, distance, and size, where much experience and some reason are required.