Nor is it difficult in their case to make up the full analogy {39} of a sense, as having an Object, an Organ, and a characteristic Sensation. In digestion, the object is the food, the organ is the alimentary canal; in respiration, the object is the air, and the organ the lungs. If it be said that the air is an impalpable agent and not discovered to the mind by its mode of operating, so is heat, the object of an admitted sense. The accurate classification of these feelings may not have much speculative interest, in Psychology, but it has a great practical interest in the diagnosis of disease. For want of subjective knowledge on the part of the patient, and of a well understood nomenclature of subjective symptoms, the discrimination of disease by the feelings is usually very rough. The best mode of arranging these sensibilities seems to be to connect them with their organs, or seats--Muscular Tissue, Bones and Ligaments, Nerves, Heart and Circulation, Lungs, Alimentary Canal. The sensations of itching and tickling are modes of skin sensibility. Tickling is an effect not well understood, although some interesting observations have been made upon it.--_B._] {40} SECTION VII. MUSCULAR SENSATIONS, OR THOSE FEELINGS WHICH ACCOMPANY THE ACTION OF THE MUSCLES. There is no part of our Consciousness, which deserves greater attention than this; though, till lately, it has been miserably overlooked. Hartley, Darwin, and Brown, are the only philosophical inquirers into Mind, at least in our own country, who seem to have been aware that it fell within the province of their speculations. The muscles are bundles of fibres, which, by their contraction and relaxation, produce all the motions of the body. The nerves, with which they are supplied, seem to be the immediate instruments of the muscular action. That these muscles have the power of acute sensation, we know, by what happens, when they are diseased, when they suffer any external injury, or even when, the integuments being removed, they can be touched, though ever so gently.