554 Prof. C. 8. Sherrington. On Reciprocal [Aug. 10, 
there is excited by the stretch a contraction in the extensor of the crossed 
knee, (3) There exist in the nerve of vasto-crureus afferent fibres which, 
under mechanical and electrical stimulation, cause relaxation of the vasto- 
crureus muscle itself.* (4) The increase of tonic length of the vasto-crureus 
muscle induced by the stretch is sometimes, under conditions favourable to 
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HIG. QA; Fie. 28. 
reflex reboundf (successive spinal induction), followed by increased contraction 
of the muscle, just as is reflex inhibitory relaxation caused by afferent nerves 
known to act inhibitorily upon it. (5) Strychnine annuls the lengthening 
* Sherrington, ‘ Roy. Soc. Proc.,’ B, vol. 77, 1906. 
+ Sherrington, ‘ Roy. Soc. Proc.,’ B, vols. 76 and 77; ‘Journ. of Physiology,’ vol. 36, 
p. 185. 
