MOTOR COORDINATIONS. 171 



the finger and the recording levers. The vertical member of the re- 

 cording levers was then adjusted to cast its shadow on the center of 

 the slit of the recording-camera. The standard instructions were 

 repeated by the operator. While the subject was entirely in position 

 and relaxed as far as practicable, a normal pulse-record was taken 

 without finger-movement. Immediately after this record a combined 

 pulse- and finger-movement record was taken as follows: When the 

 record started the operator said "go," in time with the stroke of a 

 Jaquet clock, beating seconds. After 8" the operator gave the signal 

 "stop." After a 60" rest, but without disturbing the position of the 

 subject's arm or finger, a second finger-movement record was taken 

 like the first. 



The standard instructions, repeated before each experiment, were 

 as follows: At the signal "go," move the middle finger back and forth 

 as fast as you can until you receive the signal "stop." 



Figure 28 reproduces two typical records of the reciprocal innerva- 

 tion of the finger by different individuals. They should be read from 

 left to right. The lower line in each case marks the seconds (Jaquet 

 clock) . The next line is an electro-cardiogram (body leads) ; the upper 

 line is the respiration curve. Inspiration is represented by a rising 

 curve. The oscillating line shows the finger-movements. 



Instructions to the assistants who were detailed to read finger-move- 

 ment records were to commence reading 6 movements from the begin- 

 ning in order to avoid the initial irregularities, which seem to be a 

 characteristic of the beginning of almost every finger-oscillation curve. 

 The reader then counted the number of complete oscillations in 2", 

 4", 6", and 8", respectively. Full 8" of oscillation were so rarely com- 

 pleted in legible form that they seldom appear in the results. For the 

 sake of uniformity the calculations are all based on 6" of oscillation. 



RESULTS. 



The data for the reciprocal innervation of the finger are given in 

 table 29, under the several subjects arranged in numerical order. The 

 number of complete finger oscillations in 2", 4", and 6" is entered in the 

 appropriate columns. In the earliest experiments, as for example 

 those with Subject II on October 8 and September 23, only one record 

 was taken at each experiment. In the later experiments, where two 

 records were taken, the data from both are given, together with their 

 average. Wherever available these averages are used in the elabora- 

 tion of the results. 



