One of my friends, who served as a volunteer in 1866, described to me the physical disturbances which he suffered the first time he was under fire. 'Believe me,’ he said, 'nothing can give you an idea of the furious shower of bullets which whizzed about our ears. We were near a cemetery; perhaps it was the sight of the crosses and of some corpses lying by the road-side which increased my terror, but the bullets burying themselves in the walls and trees, the cries of wounded comrades, the grim rattle of musketry, the roar of the cannon, seemed to tear me inwardly. The dysentery was so terrible that my body seemed to fall to pieces. I was always cowering in the ditches, could only stumble forwards, scarcely even rise from the ground. I was ashamed; I could have killed myself only to be able to look death bravely in the face, but, indeed, my organism could not bear that terrible sight!’ V A still more characteristic phenomenon in the picture of fear is _goose-skin_. Let us see how and why the skin corrugates in this way. We know that besides the sudoriparous glands there are other glands at the surface of the body which secrete a peculiar fat called _sebum_, which oils the surface of the skin and gives it that gloss which we notice on the face of some people. If we take a vertical section of the skin, we can see with the microscope a close network of muscular fibres which traverse the skin in an oblique direction, and surround every hair in the manner of the ribs of an umbrella. It is wonderful to see this mechanism under the microscope, how every hair has its own gland, its own muscle and its own nerve, its own arteries and veins. When these muscles contract, the meshes of the skin contract likewise and express the contents of the glands. We do not notice these movements of the skin, because the muscles contract very slowly. Sometimes special muscles appear in the skin called cutaneous muscles, which play an important part in the life of animals. We all know how the hedgehog rolls himself into a ball on the approach of danger. This movement, as we have already stated, is executed by means of a muscle covering the whole of the body, like a hood or purse which may be drawn together on one side. In the mole, too, these muscles are very strong, and we have already mentioned that dogs and horses twitch the skin to rid themselves of flies, and that this movement is due to a rapid contraction of one of these muscles. When animals curl themselves up, with the muzzle close to the tail, as the sleeping dog does, head and limbs are more easily held in this position by means of these muscles. I have found them more or less in all superior animals, and shall now consider the possible uses of these muscles which exist also in man.