258 



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



L.pop. 



Fig. 15. — Isolated de-afferented extensor muscle of right knee. Decapitate cat. 

 Faradisation of central end of right popliteal nerve for 6"5 sees., joined 2-2 sees, after 

 its commencement by faradisation of left popliteal nerve ; the latter stimulation is 

 continued until 2 sees, after cessation of right popliteal stimulation. The signal 

 marks are directed upward instead of downward as in the other records. During 

 the concurrence of the stimuli, but not when either of the two stimuli is in 

 operation alone, the muscle gives rhythmic reflex stepping ; it completes four steps 

 in about 4 sees. The muscle had been de-afferented (118 days). The proprioceptive 

 reflex — "shortening reaction" — is therefore absent on withdrawal of the contra- 

 lateral stimulus, and the muscle relaxes at once, being toneless. Time above in 

 seconds. 



