TOUCH, in fine arts, the peculiar handling usual to an artist, and by which his work may be known. In music, the resistance made to the fingers by the keys of a pianoforte or organ. Also, the pe culiar manner in which a player presses the keyboard, whether light, pearly, heavy, clumsy, firm, etc. In obstetrics, the examination of the mouth of the womb by actual contact of the hand or fingers.
In physiology, the sense through which man takes cognizance of the palpable properties of bodies. In a wide appli cation, it is sometimes called the gen eral sense, because by it we become con scious of all sensory impressions which are not the objects of smell, sight, taste, or hearing, which are called the special senses; even these, however, are held by modern biologists to be highly spe cialized forms of touch, which is often called the "mother of all the senses." In a more limited application, touch is applied to that modification of general sensibility which is restricted to the tegu mentary surface or to some special por tion of it, and which serves to convey definite ideas as to the form, size, num ber, weight, temperature, hardness, soft ness, etc., of objects brought within its cognizance. These sensations are re ceived by the terminations of the cuta neous nerves and thence conveyed to the brain. The sense of touch is distributed
ever the surface of the body, but is much more acute in some parts than in others, e. g., in the hand. It is also capable of great improvement and development; and the blind, who have to depend large ly on the sense of touch for guidance, acquire extraordinarily delicate and ac curate powers of perception with the fin gers; difference of form, size, consistence, and other characters, being readily rec ognized that are quite inappreciable to those who possess good vision, without special education.
In comparative physiology, the lower anthropida have both the hands and feet thickly set with tactile papilla, and the surface of the prehensile tail which some possess is furnished with them in abun dance. Other organs of touch exist in the vibrissa, or whiskers, of the cat, and of certain rodents. In the Ungulata, the lips and nostrils are probably the chief seat of tactile sensibility, and this is especially so with the Proboscidea. In birds, tactile papilla have been discov ered in the feet, and they are also pres ent in some lizards. Organs of touch are found in the tentacles of the Cepha lopoda and Gasteropoda, the palpi and antenna of insects, and the palpi of the Arachnida.