I am excluding conditions like split personalities, automatic writing, etc., and refer rather to normal mental processes. LECTURE XIV THE PHYSIOLOGICAL MANIFESTATIONS OF EMOTION Emotion,[196] more particularly fear, plays so large a part in the psychogenesis and symptomatology of the psychoses that it is desirable to have a clear realization of its physiological and psychological manifestations and of the disturbances of the organism which it can induce. It is not necessary for our purpose to discuss the various theories of the nature of emotion that have been propounded; we need deal only with the _manifestations_ of emotion and its effect upon the organism.[197] We will consider the physiological manifestations first. When a strong emotion is awakened in consciousness there are a large number of physiological reactions, for the most part visceral, which can be noted. Some of these may be graphically recorded and measured by means of instruments of precision. These physiological reactions are numerous and have been extensively described by Féré[198] among others. The earlier work of Mosso upon the disturbances of the respiration and vasomotor apparatus induced by sensory stimulation is well known. More recently considerable experimental work has been done, particularly by German investigators, to determine the influence of affective states upon the circulation and respiration. Modifications of the _peripheral circulation_, manifested through pallor or turgescence of the skin and measured by changes recorded by the plethismograph in the volume of the limbs; modifications of the volume of the _heart_ and of the rhythm and force of the beats recorded by the sphygmograph, and of arterial tension measured by the sphygmomonometer are common phenomena. (Fear is more particularly accompanied by pallor, and shame by turgescence—blushing. Anger in some is manifested by pallor and in others by turgescence, and so on.) Changes in rate of the heart-beats belong to popular knowledge. It is not so well known, even to physiologists that the volume of the heart may be affected by emotion. In several series of observations made under conditions of emotional excitement upon a large number of healthy men, candidates for civil service appointments, I recorded in a high percentage not only alterations in the rate and rhythm and force of the heart-beat, but temporary dilatation of the heart lasting during the period of excitement.[199] This dilatation in some cases was sufficient to lead to insufficiency of the mitral valve and to give rise to murmurs. The examination was purposely conducted so as to induce a high degree of emotional excitement, at least in many men. In another series of observations (not published) the arterial tension was measured, and it was found, as would be expected, that an increase of tension accompanied the cardiac excitation under emotion.[200] [Illustration: