282 



Reflex Nervous Discharge. 



same frequency-rate of faradisation, by direct faradisation of the motor 

 nerve itself, bears on the question whether any one afferent nerve can set 

 into action the whole of the reflex centre to which it is afferent.* 



Summary of. Conclusions. 



1. A single momentary stimulus of moderate intensity, e.g., a break-shock, 

 even though not far above threshold value of stimulation, applied to the 

 afferent nerve of a spinal reflex centre, evokes from that centre not 

 uncommonly a brief repetitive series of volleys of motor impulses. This it 

 tends to do the more the stimulus, within limits, is increased in intensity, 

 but the state of the reflex centre at the time is also a decisive factor. 



2. The rhythm of repetition of volley- discharges from the spinal reflex 

 centre is traced by the mechanical method to be of synchronous rate with 

 that of stimulation of the afferent nerve up to a frequency of 55 per second, 

 and, by a mechanical resonance method, up to a frequency of 65 per second. 

 By a " doubling frequency " method, it is shown further that the frequency- 

 rate of the reflex discharge has not reached its limit under a stimulation of 

 75 per second, but surpasses that degree, though to what extent the method 

 cannot say. 



3. The maximal mechanical power of a muscle contracting under spinal 

 reflex action is sometimes as great as the maximal which can be evoked from 

 it by direct faradisation of the motor nerve itself. 



* M. Camis, ' Journ. Physiol.,' vol. 39, p. 228 (1909). 



