The Electrical Response of Muscl( 



289 



same niouient after the stimulation of the median nerve, i.e. after 72 to locr. 

 1 f I am right in m}' interpretation of it, and if we allow from 20 to SOa- 

 for the time taken by the impulse to travel the distance of about a metre 

 along the nerve from the place of stimulation to the neck and back again, 

 and if we deduct this and the Scr taken b}" the impulse to reach the first 

 recording spot of the muscle along the motor fibres, from the 75cr, we should 

 arrive at the conclusion that 40 to 80o- had been spent in crossing the 

 synapse, or the synapses, in the part, or parts, of the central nervous 

 system concerned in such a simple reflex. 



If we examine the records taken bj^ Piper of the same thing [(2), pi. i., 

 figs. 1, 2, 3], we see also, some 860- after the first effect is over, and thus 

 some llo(T after the excitation, a very small second effect followed a little 



Fig. 9. 



•DiiTi't. and lefiex electrical resj)Oiise of the f I e x oi'e s d i git i> rii 

 break induction shock applied to the median nerve. 



later by others of the same kind. He has just drawn attention to its 

 presence on p. 399. I would suggest that it also is a reflex effect. 



The contrast between the direct and the reflex effect in fig. 9 seems to 

 me to be only an exaggeration of the contrast between the direct response 

 to artificial stimulation recorded in fig. 6 B and the voluntary response 

 recorded in fig. 6 A. The one effect is strong and single, stronger than any 

 of the effects (produced without the core in the primarj' coil) in fig. 6 B ; the 

 other effect is very weak, weaker than the voluntary response, but pro- 

 longed. This difference between the electrical effects pi-oduced when, on the 

 one hand, the motor nerve is excited by an instantaneous stimulus, and, on 

 the other, by a stinmlus coming (proximateh-) from the centre, together with 

 the fact brought out so plainly- in my experiments (pp. 228 and 241) that 

 the mechanical effect produced by the central stimulus may be so very 

 much greater than that of a series of artificial direct stimuli, sugofests that 



