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ed V and are found only near the root of the tongue; the largest of this class of papillae have other very small papillae upon their surfaces. It is now pretty satisfactorily established that the circumvallate, or fungiform papillae are the only ones concerned in the special sense of taste. The conditions necessary to taste are, that the substance be in solution either by artificial means, or by the action of the saliva; and that it be brought in contact with the sensitive filaments imbedded in the mucous membrane. The nerves of taste are both _general_ and _special_ in their functions. If the general sensibility of the nerves of taste is unduly excited, the function of sensibility is lost for some time. If a peppermint lozenge is taken into the mouth, it strongly excites the general sensibilities of taste, and the power of distinguishing between special flavors is lost for a few moments. A nauseous drug may then be swallowed without experiencing any disagreeable taste. Paralysis of the facial nerve often produces a marked effect in the sensibility of the tongue. Where this influence lies has not been fully explained; probably it is indirect, being produced by some alteration in the vascularity of the parts or a diminution of the salivary secretions. TOUCH. By the sense of touch, we mean the _general sensibility of the skin_. Sensations of heat and cold are familiar illustrations of this faculty. By the sense of touch, we obtain a knowledge of certain qualities of a body, such as form consistency, roughness, or smoothness of surface, etc. The tip of the tongue possesses the most acute sensibility of any portion of the body, and next in order are the tips of the fingers. The hands are the principal organs of tactile sensation. The nerves of general sensibility are distributed to every part of the cutaneous tissue. The contact of a foreign body with the back, will produce a similar _tactile_ sensation, as with the tips of the fingers. The sensation, however, will differ in _degree_ because the back is supplied with a much smaller number of sensitive filaments; in _quality_ it is the same. * * * * * CHAPTER XIV. CEREBRAL PHYSIOLOGY. By means of the nervous system, an intimate relation is maintained between mind and body, for nervous energy superintends the functions of both. The fibres of nervous matter are universally present in the organization, uniting the phy
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