By the application of specific drugs to the organ of taste further indications are secured that these four qualities, unanalyzable to introspection, also function in relative independence. Thus, the juice of gymnema leaves temporarily destroys the qualities of sweet and bitter, while sensitiveness to sour and salt remains unimpaired. “The true acid or sour taste may be separated from the astringent effect which accompanies it by painting the tongue several times with a five to ten per cent solution of cocaine. Cocaine first abolishes the sour taste, and after several minutes begins to abolish the astringent action of the acid solution. Later, the sour sensation begins to return, while the astringent effect is still in abeyance, so that the application of an acid solution at a certain stage during recovery enables the true taste character of sour to be differentiated.” It is also reported that when gymnemic acid and cocaine are applied to the tongue, the one abolishes the sweet and the other the bitter, thus leaving the two other tastes relatively unimpaired. Certain mixtures seem to paralyze both sweet and bitter, but the former sooner than the latter. _Distribution of the Taste Qualities_ To these four elementary tastes we are not equally sensitive on all parts of the sense organ. Roughly speaking, sweet is best tasted at the tip of the tongue, and many forms of candy are prepared so as to allow as much as possible the employment of this part of the taste organ. Bitter, on the other hand, is best tasted at the back or root of the tongue, which explains why many substances do not taste bitter until we have swallowed them. The edges of the tongue are most sensitive to sour, while in adults the central area does not commonly yield taste qualities at all. In children, however, the taste buds extend not only over the whole surface of the tongue, but are also found in the walls of the cheek, the palate, and even on the larynx and epiglottis. Titchener has suggested that these facts may explain “the childish tendency to take big mouthfuls.”