PSYCHOLOGICAL PROGRAM AND TECHNIQUE. 155 



slit in front of the camera could be opened and the photographic record 

 started by the action of a very simple lever which was not apparent to 

 the subject. The receptacle for exposed photographic paper (D in figure 

 22, page 152), below the camera, was large enough to hold more than 

 100 feet of such records. The subject's chair could be easily moved to 

 a position directly under the bar. The subject was instructed by word 

 and illustration to take hold of the bar quickly and to bring his body 

 up so that his chin was even with the bar, but not to support any 

 weight by his chin. He was to lift his feet clear of the floor and to 

 hold the position until the signal ''down." When in the chair he was 

 told to be as relaxed as possible and to act as if going to sleep. No 

 instructions regarding breathing were given. 



The experimenter commonly occupied a position which would be at 

 the left of the picture (see fig. 22). From the large clock located on the 

 wall back and above the subject the time interval could be accurately 

 judged, and the signals given; the interval of exertion was usually about 

 6 seconds. One preliminary trial was made to insure everything being 

 in proper relation and to reheve the subject of any excitement or em- 

 barrassment. He did not know that this was only a preliminary trial. 

 An interval of at least 1 minute was allowed between trials. After the 

 records had been made the subject was disconnected and the electrodes 

 were removed. It is noteworthy that the subjects did not understand 

 what this test involved. Several of them asked at different times, par- 

 ticularly at first, what it was for. The uniform answer given was : '' It 

 is a test of the involuntary nervous system." Not until January, when 

 the same electrodes were used on the men in the treadmill experiments, 

 did they realize that it was a test of the pulse-rate and heart action. 



(8) Patellar-Reflex Latency, Amplitude, and Refractory Period. 



The patellar-reflex records were made from muscle thickening. The 

 technique was the same as that used and described by Dodge and Bene- 

 dict^ in their investigations of the effect of alcohol. The apparatus was 

 essentially the same as that illustrated and described by these authors, 

 but has been sUghtly modified since the previous description. The 

 present form is shown in figure 31 , page 160, of this monograph. It had 

 been found that considerable latitude was needed for adjusting the 

 height of the light wooden bar B, which rests against the tendon of the 

 subject. A rough adjustment (1) and a fine adjustment (2) were 

 arranged to raise or lower as needed the sliding base, S, which carried 

 the stimulus apparatus and to which was fastened one end of the bar B. 

 The position of this bar in relation to the hammers, H, was constant, 

 regardless of whether the bar was raised or lowered. A screw clamp 

 (3) made possible the suitable adjustment of the height of the other 

 end of the bar. 



1 Dodge and Benedict, Carnegie Inst. Wash. Pub. No. 232, 1915, pp. 36 ff. They illustrate 

 their apparatus in their fig. 4. 



