Touch is useful only within arm’s reach but there gives one a sense of space that sight does not give. It is practically determined by the _touch corpuscles_, which are found in the skin over almost the entire body, though they are more numerous in some places than in others, the distribution of the corpuscles determining the sensitiveness of the skin. These touch corpuscles are protoplasmic bodies containing nuclei, about which are entwined filaments from the cutaneous nerves. Where the corpuscles are absent the filaments of the cutaneous nerves themselves play an important part. The finger tips have a very delicate sense of touch and the tip of the tongue is the most sensitive part of the body. Hence spaces in the mouth seem larger than elsewhere. By the transmission of sensations of touch to the brain the sensation is localized and the tactile sensation becomes a tactile perception. There are three main divisions of the sense of touch: 1. sensations of touch proper or tactile sensation; 2. sensations of temperature, and 3. sensations of pain. The temperature sense is the transmission by the skin of sensations not so much of a certain degree of heat or cold as of the difference between the temperature of an object and that of the skin. The longer an object is in contact with the skin, the less conscious the person is of it, not only because it becomes of the same temperature, but also because he becomes accustomed to it. There also seem to be in the skin, besides the touch corpuscles, two other terminal organs with separate nerve fibers, the one for detecting heat, the other cold; for there are places on the body where heat can be detected and cold cannot, and _vice versa_. Sensations of pain may be merely an exaggeration of tactile sensation, as in too hard pressure or too great heat, but there seems to be also a sensation of pain in the skin. All organs are said to have common sensibility to pain and any exaggeration of this sensibility causes a sensation of pain. All the special senses require a certain amount of judgment in the interpretation of the sensations they convey. CHAPTER III. THE CRANIUM AND FACE. The intelligence and all the special senses, except the sense of touch already spoken of, are gathered together compactly in the head, where they are carefully protected with bony tissue. Covering the brain is the skull or cranium, which is made up of eight bones, the frontal, the occipital, two parietal, two temporal, the sphenoid, and the ethmoid, while the bones of the face are fourteen in number, two nasal, two superior maxillary, two lachrymal, two malar, two palate, two inferior turbinated, the vomer, and the inferior maxillary. For the most part the bones are arranged in pairs, one on either side.