252 



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



can be shown by the same device as that employed above to reveal it under 

 similar circumstances in the extensor muscle. 



Another way in which the hidden inhibition can be revealed is by 

 administering a small dose of strychnine. It was pointed out previously 

 that strychnine converts reflex inhibition of the extensor and certain other 

 muscles into reflex excitation. I find this hold good also in regard to reflex 

 inhibition of flexors. Intravenous injection of 015 milligramme strych.. 

 hydrochl. per kilogramme (cat) almost at once converts the inhibitory effect 

 of a contralateral afferent on semitendinosus into an excitatory effect (fig. 4)_ 









■ 









I II H 







1 II II 





H 



II II 

 11 







II 





mm 



1 



HI H^fl 







■ H 

 1 1 







Fig. 4. — Effect of stimulation of contralateral peroneal on Semitendinosus ; A, before- 

 strychnine ; B, after. In B the contraction of vastocrureus is not included, but 

 semitendinosus (ST), which had shown no contraction in A, because the stimulus was- 

 inhibitory to it, in B under the same stimulus exhibits the marked contraction 

 shown, the small dose of strychnine having converted reflex inhibition into reflex 

 excitation. The contraction long outlasts the period of stimulation in B. 



Stimulation of the afferent then, in the resting preparation, instead of 

 leaving the muscle apparently untouched, produces reflex contraction of it.. 

 The influence on the flexor motoneurones, which was previously unable to 

 show itself in the relaxed muscle, because inhibitory, at once reveals its 

 existence, because under strychnine it has become an excitatory influence; 



