124 THE HORSE OF MR. VON OSTEN 



the degree of concentration of attention, — ^and when this 

 was very great, it was even possible to get a clue as to 

 the number thought of. Since the high degree of ten- 

 sion, under which a subject labored during a test, would 

 be accompanied by strong affective coloring, we cannot 

 regard as normal any of the curves here reproduced 

 (with the exception of the two high points in figure 9). 

 Although breathing was always deep and regular before 

 and after a test, during the test it was less deep and ir- 

 regular. Very often it was suspended altogether (figures 

 7, 8 and 9). In ordinary life we often notice that highly 

 concentrated attention is usually accompanied by non- 

 voluntary inhibition of movements in the musculature 

 which, for the moment, is not directly involved ; the man 

 lost in thought slackens his pace and finally stands still, 

 the intent listener or looker-on holds his breath. 

 — N,Of the three curves registering the movements of the 

 head, we find that nothing peculiarly characteristic is 

 revealed by the two upper ones, giving the movements 

 up and down, and to the right and left, respectively. 

 They are the ordinary tremor-like movements and in- 

 dicate nothing beyond the fact that the subject is unable 

 to hold his head absolutely quiet for even one second. 

 It is the third line that is of interest to us, for it is here 

 that the oft-mentioned head-jerk (which indicates arrival 

 — in the counting — at the number expected) registers 

 itself. The moment of the head-jerk corresponds, almost 

 without exception, with the moment of the first deep 

 inhalation, — just as one would be led to expect from 

 common experience. But we are not to regard the head- 

 jerk as a result of the inhalation, for it also occurs when 

 the subject complies with the request that he hold his 

 breath during the test. The actual height of the jerks 



