166 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



The exposure apparatus E (see figure 31, page 160) when used is slipped 

 into position at the end of the kymograph and clamped to the post P. 

 The stimulus words were visible to the subject through the window W. 

 The voice-key V is connected with flexible cables and may be used in 

 any convenient position. The voice-key is the one used by Dodge and 

 Benedict, and described and figured by them in their publication.^ 

 The exposure apparatus was also the same as that described by Dodge 

 and Benedict in their figure 30, which shows the construction of the 

 back of the apparatus not visible to the subject. 



One modification which greatly facilitated the taking of reactions 

 with this exposure apparatus was in the chp which holds the card in 

 position for exposure at the end of the movable arm. A holder was 

 substituted which would contain a pack of 25 cards, each card having a 

 stimulus word printed on it. Thus, following a reaction, it was only 

 necessary to lift the arm of the exposure apparatus and withdraw the 

 card bearing the word which had just been reacted to; the apparatus 

 was then ready for the next reaction when the movement of the kymo- 

 graph shaft broke the circuit and caused the second stimulus word to 

 come into view in the window. Previously, when it was necessary to 

 put in a card before each reaction, as well as withdraw the one which 

 had just been reacted to, it was not possible to take reactions faster 

 than one in every 10 seconds. This made the measurement somewhat 

 tedious, or at least it appeared so with certain subjects.^ With the 

 pack arrangement of the stimulus cards it was easily possible to take 

 reactions every 5 seconds, and had there been a convenient kymograph 

 speed the time could have been still shorter without inconveniencing 

 the subject or the experimenter.^ 



The position of the exposure device, with reference to the subject and 

 to the other items of apparatus, is shown in figure 31. The subject sat 

 in a position which would be at the extreme left in this figure. The 

 voice-key V was held in the right hand and the arm was supported on a 

 convenient rest not shown in the picture. Thus the moving kymo- 

 graph drum and other distracting features of the apparatus were 

 hidden from the view of the subject, as the exposure apparatus occu- 

 pied the greater part of his field of view. The area about the window, 

 where the stimulus words appeared, was a light gray."* 



1 Dodge and Benedict, Carnegie Inst. Wash. Pub. No. 2.32, 1915, p. 99, fig. 16. Photographic 

 records for the latency of the voice-key as connected with different signal markers, and for the 

 pronunciation of different words are given by them in their figs. 17 to 20. 



2 Miles, Carnegie Inst. Wash. Pub. No. 266, 1918, p. 66. 



3 Reference should be made to fig. 28, p. 157, for the wiring diagram for the word-reaction 

 apparatus. 



* In the previous use of this apparatus (Dodge and Benedict, Carnegie Inst. Wash. Pub. No. 

 232, 1915; Miles, Carnegie Inst. Wash. Pub. No. 266, 1918) the exposure device was placed at the 

 other end of the kymograph. (See Dodge and Benedict, p. 95, the lower right-hand corner of fig. 

 14.) The subject occupied the same position as in the pre.sent research, and thus had the moving 

 kymograph in his field of view when he was reacting to the words presented by the exposure 

 apparatus. 



