The senses of taste and smell are intended to convey impressions resulting from the chemical qualities of bodies, the one in the fluid, the other in the gaseous state. There is a considerable analogy between the sensations derived from these two senses. The organ of taste is the surface of the tongue, the skin of which is furnished with a large proportion of blood-vessels and nerves. The vascular plexus immediately covering the corium is here very visible, and forms a distinct layer, through which a great number of papillæ pass, and project from the surface, covered with a thin cuticle, like the pile of velvet. In the fore part of the human tongue these papillæ are visible even to the naked eye, and especially in certain morbid conditions of the organ. They are of different kinds; but it is only those which are of a conical shape that are the seat of taste. If these papillæ be touched with a fluid, which has a strong taste, such as vinegar, applied by means of a camel-hair pencil, they will be seen to become elongated by the action of the stimulus, an effect which probably always accompanies the perception of taste.

The primary use of this sense, the organ of which is placed at the entrance of the alimentary canal, is evidently to guide animals in the choice of their food, and to warn them of the introduction of a noxious substance into the stomach.