The balancing of the body which occurs even in standing, much more that of walking, running or flying, is the result of a very complicated series of movements, numerous muscles antagonizing one another by regulated contraction, so that just the right position may be secured. To preserve the equilibrium innumerable unfelt impulses are continually passing from the eyes, from the semicircular canals, from the various muscles employed, up to the nerve-centres in the lower brain, where they are, as it were, assorted and reflected back as co-ordinated or arranged impulses to all parts of the muscular system, and produce just such contractions as are required for the purposes of equilibration and locomotion. When a child is learning to walk it is simply educating this intricate machinery and developing its latent powers. Very much as the will of man aids a setter in developing the natural instinct to hunt, so does the child's will direct, check and in every way assist the complicated and delicate machinery which presides over locomotion. Perhaps a better comparison is to be found in the drill-sergeant training and educating his squad of men, who at first are utterly unable to obey his will, but who by his reiterated efforts are finally so trained that they move as one piece in strict obedience to his word or go through complicated man[oe]uvres without command. No wonder the child requires so many days of effort to get all its delicate machinery of walking, running, etc. so trained that it works smoothly and without conscious effort of the will. But as the training becomes more complete, the lower brain becomes more and more independent of the conscious will which resides in the upper brain or cerebrum, until at last the automatic action is so perfect that walking without consciousness is possible. Very many of my readers have no doubt in their younger days, when hard pressed with a lesson, walked to school studying as they went, their attention riveted on the book, their feet carrying them along the well-known pathway. Under such circumstances consciousness does not direct progression. Walking in the sleep is only one step beyond this. In the days of Antietam a friend of the writer's, worn out with the forced marching, whilst on guard as a sentinel, erect and soldier-like in posture, slept until the dark lantern of the relief officer appalled him with its sudden flash. Once after a long tramp I myself, laden with a heavy pack, nearing home, trudged in the unconsciousness of sleep along the oft-trodden road. In the cavalry raids around Richmond during our late war it was not very unusual for men and beasts to become so exhausted that both would go to sleep on the homeward night-march when they were straining all their powers to escape. The whole regiment asleep, horses staggering along in loose order, men swaying to and fro in their saddles, when there was a sharp turn in the road it was necessary to post sentinels to waken the