has something to do with their inferior æsthetic value? However this may be, it is clear that the mere variety of impressions afforded is not the criterion of which we are in search. One might be tempted to suppose that the sharpness of discrimination of the various senses, the keenness with which differences in the strength and intensity of impressions can be detected, might be an important factor in determining their availability for æsthetic manipulation. The figures given in the table under this heading indicate the proportion that must be added to a stimulus in order to make it just perceptibly more intense. The temptation is removed at once by a mere inspection of the values. Sight is, to be sure, the most delicate of the senses in this respect, as it is also in number of isolable qualities. But kinæsthetic sensation follows close upon it, while smell stands third in the list, and hearing is no more sensitive than pressure. In the case of taste and the other senses the values are unknown or difficult to determine, but it is clear that the æsthetic values of the different senses do not depend merely on their various psychophysical constants. The quickness with which one can react to or perceive impressions from the various senses discloses much the same state of affairs. Basing our comparison on the average reaction times to the most commonly available impressions and intensities in each case, hearing, touch, and temperature are seen to be about equally prompt, while sight stands fourth on the list. With respect to the period of time through which a sensation continues to persist, the so-called “life span” of an impression, only three of the values, those for sight, hearing, and touch, have been determined, and these bear no significant relations to each other. But these times are all very short, and the corresponding modes of sensation stand high in the æsthetic scale. The other values, although not determined, are known to be much longer than these. Is it possible that the sluggishness of these senses and the persistence of impressions once set up through them is so great that the impressions do not submit to the forms, patterns, and structures which constitute artistic treatment? Or may it not be equally true that the fugitive character of impressions from the higher senses is what has made necessary the development of treatment by means of pattern and structure? _The Tendency to Adaptation_