After the numerous researches made, during the last twenty years, into the nature and the revivability of visual, auditory, tactile-motor, and verbal images, it seems paradoxical to maintain that there is still an unexplored region in the domain of memory. As a matter of fact, however, we find at most a few scattered remarks on the images derived from smell, taste, internal sensations, pleasure, pain, and emotion in general. The question of the emotional memory remains nearly, if not quite, untouched.[96] The object of this chapter is to begin its study. ----- Footnote 96: I see no reason for mentioning any authorities except H. Spencer, _Principles of Psychology_, i., §§ 69 and 96; Bain, _Emotions_, ch. v.; W. James, _Psychology_, ii. pp. 474, 475; Fouillée, _Psychologie des Idées-forces_; Höffding, _Psychologie_ (3rd German edition), vi., B. 3; Lehmann, _Hauptgesetze_, pp. 261-263. ----- The impressions of smell and taste, our visceral sensations, our pleasant or painful states, our emotions and passions, like the perceptions of sight and hearing, can leave memories behind them. This is a matter of common experience on which it is needless to insist. These residua, fixed in an organisation, may return into the consciousness; and it is known that images may be revived in two ways—by provocation, or spontaneously. Revivability on provocation is the simplest of all. It consists in an actual occurrence awakening the images of similar occurrences at some former time, and takes place, beyond possibility of doubt, in the class of images which occupies us just now. The actual sensation of fatigue, of the smell of a lily, of the taste of pepper, of pain in a certain tooth, appear to me as the repetition of sensations formerly experienced, similar to the present one, or at least apparently identical, so that, consequently, it revives them. But can the images of olfactory and gustatory sensations, of internal sensations, of past pains and pleasures, of emotions formerly experienced, be revived in the consciousness spontaneously, or at will, independently of any actual occurrence which might provoke them? We know that, in some painters, the inner vision is so clear that they can draw a portrait from memory; that, in some musicians, the inner hearing is so perfect that they can, like Habeneck, ideally hear a symphony just played, recalling all the details of the execution, and the slightest variations in the time. Are there in the order of emotional representations any cases analogous to these? Such is, in its precise form, the question which we shall examine in detail. We shall subsequently see that it has a practical bearing, and is not a mere psychological curiosity. Before entering on the subject, I will summarise the principal facts relating to this question to be found scattered through the works of various authors. I divide them into four groups:—