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Prof. C. S. Sherrington. Reciprocal [Mar. 25, 



immediately becomes effective (or more effective) on withdrawal of the con- 

 current inhibitory stimulation (fig. 2). 



Similarly with flexor muscles. The flexors of the knee can be suitably 

 studied with semitendinosus or bicejjs femoris. With the latter, the posterior 

 part only of the muscle need be used, the anterior part not being a true knee 



Fig. 1. — Reflex contraction of Vastocrureus in spinal mammal (decapitated cat), excited 

 by faradic stimulation of contralateral popliteal nerve (C). During this contraction 

 the ipselateral peroneal nerve was faradised for the time shown by the lower signal (I), 

 and produced a lessening of the reflex contraction ; this inhibitory effect is greater 

 according as the intensity of the stimulation of the ipselateral nerve is increased. In 

 the second observation it reduces the reflex contraction to less than half ; in the third 

 observation it suppresses it altogether for so long as the inhibitory stimulus endures. 

 In the third observation, with the strong inhibition, so abrupt and quick is the 

 suppression of the contraction that the writing lever gives a vibratory shake at the 

 end of its fall. The tremor seen to occur in the second observation during the period 

 of concurrent excitation and inhibition is usual, and is more marked in the decapitated 

 preparation than in the decerebrate. Time in seconds above. 



flexor (cat, dog). The muscle, e.g., semitendinosus, is isolated by detachment 

 from tibia and by severance in both hind limbs of all nerves other than its 

 own. The reflex contraction or relaxation of the muscle can then be studied 

 by the myograph. Keflex contraction is easily obtained by stimulation 



