The classical senses, vision, hearing, touch, taste, and smell, were first conceived as the windows of the soul. Later, and even up to the present, they were conceived as distinct channels by which messages were sent to the brain. Each has an obvious and seemingly isolated organ. The simplicity of this scheme began to break up in the nineteenth century. The list of senses had to be extended. Kinaesthesis was added, but it had to include the sense of position of the body as well as of movement. The equilibrium sense was discovered, its organs being part of the inner “ear” or labyrinth. Temperature and pain were added, or else made subdivisions of the skin sense. Touch itself proved to be complex. The senses were classified by Sherrington as exteroceptive, proprioceptive, and interoceptive, but these classes do not now appear to be mutually exclusive.