256 Prof. C. S. Sherrington. Nervous Rhythm [Feb. 3, 



fig. 4 and fig. 5, both from the same experiment ; also for that between the 

 observations of fig. 1 and fig. 10, both from the same experiment. As drawn, 

 the diagram applies to extensors (of knee), but by reversing inhibition to 

 excitation and conversely it is applicable to flexors (of hip and knee). 



4. Influence of the Sequence. 



It is noticeable that the effect of concurrence of the stimuli opens with 

 a result in the direction of that of the added stimulus practically at once on 

 addition of that stimulus. Under the concurrence the newer stimulus tends 

 to dominate at once. This is in harmony with experience on visual rivalry, 

 struggle between rival contours, etc. The very newness of the new stimulus 

 lends it force as against the pre-existent, especially where the pre-existent is 

 not very much the more potent and has been in operation for some time. 



Probably a similar relation explains why although well-acting combinations 

 of the antagonist stimuli produce the rhythmic reflex whichever of the two 

 stimuli precedes, with less effective pairs of stimuli that is not the case. It 

 appears with the latter a point material for the result which of the two 

 precedes and which follows (fig. 2). The rhythmic reflex may be much better 

 if x precede y than vice versd, or it may not appear at all in one sequence 



LVCr. 



R.jper. 

 L._per. 



Fig. 14. — Isolated extensor muscle of right E.V. and left L.V. knees. ynchronous 

 stimulation of both right and left peroneal afferents (R. per.), (L. per.) The reflex 

 opens with identical contraction of both the muscles, but almost immediately the 

 reaction of the left muscle is changed to inhibitory relaxation, with the result that 

 the symmetrical muscles fall into step with reciprocal harmony. Decerebrate cat. 

 Time above in fifths of seconds. 



