Resembling jelly or glue, uncrystalline in character. Indeed, it is true that there are substances which have more than one taste, the taste varying with the region of the tongue at which the substance is applied. Thus saccharine, sulphate of magnesia, and acetate of potassium are said to have sweet or acid taste if applied to the side or tip of the tongue; whereas they are bitter if applied to the posterior part. There are various other substances which show similar changes in taste according to the point of their application. However such facts may be explained, it is clear that the classification of taste along chemical lines is not only beset with difficulties, but that even in attempting such classification we resort to the use of a more immediate classification, indicated by such words as sweet, sour, etc. This resort to an immediately descriptive classification suggests that the various taste experiences, regardless of the stimulus provoking them, have certain similarities as direct experiences. This further suggests that a strict psychological classification, based on the attributes of tastes themselves, should be found through analysis. In the case of sensations in general, such a type of classification is the one that seems most satisfactory. Certain sense experiences, such as red, yellow, orange, seem, as a matter of immediate experience, to belong together and to be essentially different from such experiences as warmth, tickle, noise, dizziness, etc. Furthermore, it is found possible to pass by gradual steps of transition from red to yellow, through an intervening orange, while there exists no such intermediate region between red and tickle. As a matter of immediate experience, then, and regardless of the nature of the stimulus, or, so far as we may be aware, of the part of the body stimulated, certain sense experiences seem to belong together, to constitute a certain _mode_ of sensation, such as pressure, sound, etc.