These divergent accounts of the elementary taste qualities are in large measure to be explained by the exceeding complexity of those experiences which we in everyday life refer to as “tastes.” It was long ago shown that a classification of the various senses on the basis of the gross “sense organs” or parts of the body involved is as inadequate as one based on the nature of the stimulating agent. The eye as a gross sense organ yields experiences of pressure, pain, temperature, and strain, as well as experiences of color and brightness. But these varied sensations we recognize as belonging, as experiences, to quite distinct modes. Even more complex are the varied sense experiences which we may receive through stimulation of the tongue and the surrounding tissues. For the tongue as an organ yields not only sensations of pure taste quality, whatever these may be, but it also gives rise to experiences of pressure with the varying characteristics of smooth, rough, moist, dry, contact, tickle, etc.; to experiences of pain, with the ranging characteristics and intensities, such as sting, smart, prick, burn; to experiences of temperature, such as cold, warmth, heat; and to a vast complex of kinæsthetic or muscular experiences of contraction, torsion, strain, expansion. In common experience these qualities of pressure, pain, temperature, and kinæsthesis are scarcely discriminated from the purely gustatory or taste qualities themselves. Thus we speak of “oily,” “fatty,” and “greasy” tastes, in which the “smoothness” is certainly identical with that felt by the fingers and other parts of the skin. Similarly the pungent, astringent, puckering, biting “tastes” may come from substances which have no taste at all in a strict sense, but which produce definite smarting or stinging sensations when applied to the surface of the skin or to exposed nerve endings (pepper, camphor). The puckering quality can be shown by the characteristic muscular reaction to be largely kinæsthetic and tactual in its origin. The difference in “taste” between cold ice cream and the same substance when melted indicates how much of the flavor is due to touch sensations and sensations of temperature. One observer, indeed, reports the experience of four different qualities of sensation from the stimulation of a single papilla,—a touch, a temperature, a taste, and a pain sensation.