Reflex Nervous Discharge. 279 



proximal to anode on the afferent nerve), the sole stimulation-change accom- 

 panying the contraction-increment is the increased number of stimuli per 

 second. This increase of contraction-height on increasing (doubling) the 



D 



Fig. 5. — Reflex contractions of tibialis anticus (spinal cat), showing efi'ect of intercurrent 

 doubling of frequency rate of interrupter in primary. A and B, initial (and 

 terminal) rate of stimulation, 65 per sec. ; intermediate period, shown by higher 

 plateau of contraction, at 130 per sec. In B the order of succession of the twin 

 branches of the circuit is reverse of that in A. C and D similar, but with rate of 

 75 per sec. (doubling to 150 per sec.) ; the increase of height of the plateau obtained 

 by doubling is still obvious, though less than in A and B. The signal, as set for the 

 slower rate of interruption, has failed to pick up the quicker rate. 



stimulation frequence was observed in experiments carrying the initial, i.e., 

 undoubled, frequence of stimulation up to 75 per second. When that rate 

 was reached the increment of contraction- height obtained by further increase 

 (doubling) became quite small, though still quite indubitable. The rate of 



