WEEKLY EVENING MEETING, 

 Friday, February 4, 1921. 



Sir James Reid, Bart., G.C.V.O. K.C.B. M.D. LL.D., 



Vice-President, in the Chair. 



A. D. Waller, M.D. LL.D. D.Sc. F.R.S. 

 The Electrical Expression of Human Emotion. 



We are all of us familiar, subjectively within ourselves, objectively 

 by the behaviour of our neighbours, with the signs and symptoms of 

 emotion, and with the fact that such signs and symptoms are more 

 or less under voluntary control and can be suppressed or simulated 

 at will. We are moved to or from an object we may desire or fear. 

 We are moved to laughter or to tears by events witnessed and 

 imagined ; and whereas all men are moved in the mass by the same 

 general motives of light and dark, food and hunger, love and hate, 

 we know by everyday experience that no two men react in identical 

 fashion to the same motives. 



1. Physiologically, all emotions are expressed as neural outbursts 

 from the central nervous system through efferent nerves to muscles 

 and glands ; emotion, in general, results in intensified physiological 

 activity at the periphery of the body — muscles and glands, heart and 

 blood-vessels, the face and eyes and skin. A movement of surprise, 

 a palpitation of the heart, a blush, a pallor, a shiver, a rush of tears, 

 a dilated pupil — all these and other signs of emotion consist in 

 sudden local intensifications of the chemical exchanges that are in 

 constant operation between the living cells of the body and the fluid 

 medium by which they are surrounded. We know indeed that all 

 such chemical exchanges are controlled through efferent nerves, and 

 we speak of this control as their trophic action, but we are scarcely 

 prepared at the present day to recognise the close association between 

 signs of emotion and the phenomena of nutrition. 



2. The physical sign of emotion is known to psychologists as the 

 psycho-galvanic reflex. It was first definitely revealed to us twelve 

 years ago by Yeraguth,* of Zurich, and has since then formed a 

 favourite subject of study by many later observers whom I shall not 

 attempt to enumerate. I joined in the hunt four years ago,f and 



* "Das Psychogalvanische Reflexphenomen." (Berlin, 1900.) 

 f " The Galvanometric Measurement of ' Emotive ' Physiological Changes. " 

 Proceedings of the Royal Society, B, vol. xc, p. 214, 1917. 



Vol. XXIII. (No. 115) x 



