196 II. Psychical Compounds. physical concomitants stand in no constant relation to the psy- chical quality of the emotions. This holds especially for the effects on pulse and respiration, but is true also for the pan- tomimetic expressive movements. It may sometimes happen that emotions with very different, even opposite kinds of affective contents, may belong to the same class so far as the accompanying physical phenomena are concerned. Thus, for example, joy and anger may be in like manner sthenic emotions. Joy accompanied by surprise may, on the contrary, present the appearance on its physical side of an asthenic emotion. 7b. The general phenomena of innervation which give rise to the distinction between sthenic and asthenic, and rapid and sluggish emotions, do not show the character of the affective contents of these emotions, but only the formal attributes of the intensity and rapidity of the feelings. This is clearly proved by the fact that differences in involuntary innervation analogous to those which accompany the different emotions, may be pro- duced by a mere succession of different impressions, as for example by the strokes of a metronome. It is observed in such a case that especially the respiration tends to adapt itself to the faster or slower rate of the strokes, becoming more rapid when the rapidity of the metronome increases. Commonly, too, certain phases of respiration coincide with particular strokes. Furthermore, the hearing of such an indifferent rhythm is not unattended by emotion. When the rate changes, we observe at first a quiet, then a sthenic, and finally, when the rapidity is greatest, an asthenic emotion. Still, the emotions in this case have to a certain extent a mere formal character; they exhibit a great indefiniteness in their contents. This indefinite- ness disappears only when we think into them concrete emotions of like formal attributes. This is very easy, and is the con- dition of the great utility of rhythmical impressions for describ- ing and producing emotions. All that is necessary to arouse an emotion in all its fulness, is a mere hint of qualitative affective content, such as it is possible to give in music through the clangs of a musical composition. 7 c. The external expressive effects of emotions are, accord- ingly, ambiguous symptoms and can, therefore, have, when taken by themselves, no psychological value. They may, however, acquire such value when connected with introspection which has been properly provided for in an experimental way. Indeed,
