TASTE (OF. taster, F. toter, to taste, front Lat. *taxitare, frequentative of ta.rare, to touch, intensive of tangere, to touch; connected with tekan, Icel. take, AS. taean, Eng. take). The tongue is supplied with nerve endings which not only (like those of the skin) mediate sensa tions of pressure, temperature, and pain, but also furnish sensations of taste. The nerve endings eoncerned in gustatory sensation are the taste bulbs or beakers, many of which are clustered together in the sides of each circumvallate and fungiform papilla (the filiform are in sensitive to taste). Taste sensations enter con sciousness highly fused with pressure, tempera ture, and notably with smell sensations; e.g. the flavor of wine is largely smell. Hence it is not strange that the number of elementary taste qualities has hut recently been determined. Linn ens gave a list of 20 qualities; another early writer 10; modern methods have lowered the number to 4: sweet, bitter, sour, and salt, to which Wundt adds, doubtfully, alkaline and metallic. See TONGUE and accompanying illus trations.
If the tongue be experimentally explored by stimulating individual papillae with four solu tions (usually sugar, quinine, tartaric acid, and salt), it will be discovered that most papilla: are selective; e.g. one may react only to sweet, another only to salt and sour, a third to sweet, salt, and sour, etc. That such differences should appear is but natural, for each papilla is. in reality, a cluster of taste evils. Now it is possi ble so to treat a papilla which has yielded more than one taste as to destroy temporarily its re action to one of these tastes without destroying its sensitivity to the others; thus a 20 per cent. solution of cocaine hydrochlorate will eliminate bitter alone. From these facts, it is warrantable to assume that the doctrine of specific sense en ergies applies to the tongue. The recent work
of Kiesow and Nadoleczny (stimulating the chorda tympani at a point near the internal ear) seems to establish the possibility of inducing specific taste sensations by inadequate electrical stimulation; pressure yields more doubtful re sults.
Kiesow has shown that the tongue is not equally sensitive over all its surface; the tip is best for sweet, the base for bitter (pressure here seems at times to arouse bitter), the sides for sour. Sensitivity to salt is about equal over all the surface. Recent experimentation has estab lished beyond much doubt the existence of taste contrasts, both simultaneous and successive. The contrasting pairs are sweet-salt, sweet-sour, salt sour : bitter does not contrast with any taste. The stimulation of the tongue by one member of these pairs increases its sensitivity to the other mem ber. or causes distilled water to give the con trasting taste. As in the cases of vision and smell (qq.v.), taste contrasts imply taste com pensations. A mixture of sugar and salt in proper proportioni, is insipid. From these facts, Kiesow has constructed a two-dimensional taste continuum—a square whose opposite corners are sweet and salt, bitter and sour. Mixtures of adjacent terms will, then, give an intermediate, mixtures of opposite terms, an insipid taste.
BIBLIOGRAPHY. Kuelpe, Outlines of Psychology Bibliography. Kuelpe, Outlines of Psychology (London, 1895) ; Hofman and Bunzel, Pthiger's lxvi. Kiesow and Nadoleczny, Zcitsehrift fiir Psychologie and Physiologic, xxiii. (1900) ; Kiesow, Philosophische Studien, x. (1894), xii. (1890): Titchener, Experimental Psychology (New York, 1901) ; Vintschgau, in Hermann's Handbuch der Physiologic, iii. ( ISSO) Zeyneck, Centralblett fiir Physiologie, xii. (1898).