PSYCHOLOGICAL PROGRAM AND TECHNIQUE. 



157 



for the apparatus as used is shown in schematic form in figure 28. The 

 meaning for the different letters is given in the legend of this figure. 



The subject reclined in a steamer chair, the height of which was the 

 same for all subjects and all sessions. At first the patellar tendon was 

 explored to find the point of greatest sensitivity. Then, beginning 

 with the stimulus 

 blows separated 

 by an interval 

 of 0.8 second or 

 thereabouts, the 

 interval was grad- 

 ually shortened 

 until the second 

 stimulus failed to 

 produce a reflex. 

 Then the interval 

 was varied in 

 length a number 

 of times in an ef- 

 fort to secure sev- 

 eral records in 

 which the second 

 stimulus pro- 

 duced only a slight 

 reflex or no reflex 

 at all. The 100- 

 gram weights did 

 not seem to be 

 uncomfortably in- 

 tense for any sub- 

 ject. Some of the subjects had no reflex which was measurable 

 routine was carried out, however, in every instance, so that if a reflex 

 should suddenly appear or become sensitive it would not be omitted. 

 This did happen to some extent in the case of Tom, Squad A, who, 

 after an operation for hemorrhoids,^ had a reflex which was considerably 

 larger than that he had previously shown in the experiment. A sample 

 record, reduced in size, is given in figure 29. The records for patellar 

 reflex, finger movements, and word reactions taken on the subject in 

 room B were all made on the same kymograph paper. The reader will 

 therefore disregard for the present the part of the record below the 

 cross which may be seen on the left side of figure 29. The reflex record 



(see upper part of fig. 29) was started near the middle of the paper, 

 where the interval between reflexes is longest. Reading a record from 



Fig. 28.— Schematic wiring diagram for the apparatus used in 

 room B in the evening measurements: patellar reflex and 

 word reactions. 



A triple pole switch T and a double pole switch D, when closed, caused 

 current to flow in the electro-magnets M, which held up the pen- 

 dulum hammers used to stimulate the patellar tendon for elicit- 

 ing the reflex. The hammers were released from the magnets 

 when the circuits were broken at B and B'. The temporal re- 

 lation of these could be changed (see fig. 27). A large clock C 

 interrupted a circuit (110 volts, lamp L, in series, 0.5 amp. cur- 

 rent flowing) and so actuated an electro-magnet, 1, and reg- 

 istered the control time on the kymograph K. By opening D 

 and connecting the exposure apparatus E in circuit by means of 

 the plug P, the word reactions could be recorded. The open- 

 ing of the circuit at B' exposed the word and caused at that in- 

 stant the operation of the marker, 2. The circuit was reestab- 

 lished at B' before the subject could react by speaking into the 

 voice key V. The reaction opened V and the marker, 2, was op- 

 erated a second time and recorded the moment of response. 



The 



1 See his personal history, p. 52. 



