April 7, 192 1 J 



NATURE 



185 



a pin-prick or the lighting of a match. High in the 

 scale of imaginatives we not infrequently meet with 

 people who can at will either keep quiet, or think 

 thoughts and see visions and hear words of purely 

 imaginary existence without objective physical sub- 

 stratum. It is very interesting to watch the galvano- 

 metric signs of subjective phenomena — interesting to 

 the onlooker, but far more interesting to the subject 





/AM. 



,..y. 



$ 



Fig. 2.— Emotivity of A. M. W. during the air-raid on Whitsunday, 1918. 

 (From the Lancet.) M indicates the time of the first warning by 

 maroons at 11 p.m. G indicates the commencement of gun-fire. 

 The duration of the disturbance was from 11.20 p.m. to i.^jo a.m. 

 H marks the moment of maximum alarm, when the swelling hum of 

 approaching aeroplanes was most audible. S indicates the second 

 warning by siren at the termination of the disturbance. The electrodes 

 were transferred from the left to the right hand at 12.5. The hori- 

 zontal lines D.N.-N.N. indicate the average normal day and niebt 

 conductance of A. M. W., ascertained from other observations. 



-50y 



Fig. 3. — Galvanometric record of G de D. during the air-raid of January 

 29, 1918. (From the Lancet.) At the tenth minute of observation 

 the noise of maroons, mimediately followed by that of aeroplanes and 

 guns, broke out, and the resistance, which was approximately 60,000 

 ohms during the first ten minutes before the disturbance, fell to ap- 

 proximately 2o,coo ohms during the next 15 minutes. (On the left 

 hand is given the resistance in thousands of ohms, and on the right 

 the conductance in gtmmhos.) The measurements are as follows :— i,*' 



I 



... 8.30 p.m. 



- 8.3s „ 

 ... 8.40 „ 



- 8.45 „ 



20 8.50 ,, 



25 8.S5 „ 



At 11.30 (all quiet) ... 



56 X tooo ohms or i8y 



15 



I9V 

 377 

 457 

 5°y 

 507 

 23Y 



who knows what he (or she) is thinking about. And 

 when it is realised that the galvanometer answers 

 to one's thoughts and temper, it becomes quite an 

 absorbing pastime to sit quietly in an armchair and 

 watch oneself think as one watches the galvanometer 

 move. 



NO. 2684, VOL. 107] 



8. The emotive response is liable to all manner of 

 variations. It varies in different individuals, and in 

 the same individual it varies with different states of 

 mind and body. It varies in magnitude and in its 

 distribution over the limbs with variations in the 

 magnitude of its exciting cause. While it is, in the 

 mam, an uncontrollable phenomenon, 1 call to mind 

 more than one case where to all appearance it has 

 been influenced at will. 



9. The distribution of the response over the body is 

 especially interesting. In normal persons it is ex- 

 clusively palmar (and plantar); the rest of the body- 

 surface is silent. But in "sensitives" it extends up 

 the limbs and the trunk. And a border-land person, 

 according to his state of temper, can react normally 

 to-day, but as a "sensitive" to-morrow. The few 

 spiritualistic mediums whom I have examined have 

 (with one doubtful exception) given the reaction proper 

 to " sensitives," i.e. in the hand and in the forearm. 



10. The diurnal variations of the reaction attracted 

 my attention at the very outset of the inquiry. I soon 

 noticed that the same people, when submitted to a 

 standard stimulus at diflerent times of the day, gave 

 responses of very different magnitudes ; the responses 

 were at their best about the middle hours of the day, 

 when physiological activity is high, as compared with 

 what was elicited early in the morning and late at 

 night. And the conductivity of the palm of the hand 

 rose and fell during the day (as does the temperature). 



I thought it necessary to investigate this diurnal 

 periodicity rather closely to learn how much it might 

 be necessary to take into account the time of day 

 when comparing results obtained on difTerent indi- 

 viduals. So I watched this periodicity on my own 

 hands by means of apparatus set up for the purpose 

 in my dressing-room, so that observations of con- 

 ductivity could be taken at any convenient time. The 

 observations were recorded to form a graph on 

 squared paper; and it may be remarked, by the way, 

 that throughout the observations the conductivity of 

 my right hand has been found to be higher than that 

 of my left hand. 



11. The three weeks over which these observations 

 extended afforded me an admirable opportunity of 

 observing the galvanometric effects of my own normal 

 variations of "temper." Most people are more or 

 less conscious of what may perhaps be called varia- 

 tions of euphoria before breakfast, and of very dis- 

 tinct, if not outwardly evident, variations of euphoria 

 when the morning's letters are read. In order to test 

 this point a photographic recorder was set up in con- 

 nection with the galvanometer on my dressing-table 

 and I had my letters brought up there and read to 

 me and signalled on the recording plate. Most of the 

 letters made no impression upon me, but I well 

 reijiember one fortunate morning on which the post 

 included two distinctly effective letters which produced 

 marked effects duly recorded on the photographic plate. 



12. One is naturally tempted to ask what relation 

 there may be between the magnitude of the reaction 

 and the mental quality. A first step towards an 

 answer to this question has been taken by" Miss 

 Waller, who has made systematic measurements of 

 seventy-three students of medicine, divided according 

 to examination results into an upper and a lower divi- 

 sion. The average response was higher in the former 

 than in the latter — e.g. to disturbing questions the 

 average value of the response came out about 50 per 

 cent, higher in the upper division.* 



13. I have often been asked whether pleasant and 

 painful sensations produce similar or opposed galvano- 



* Mary D. Waller, "The Emotive Response of a Cla.ss of Seventy- 

 three Students of Medicine measured in Correlation with the Result of a 

 Written Examination," Lancet, April 6, 1918. 



