. On Innervation of Antagonistic Muscles. Ninth Spinal Induction . ickly becomes again elicitable, and soonis more brisk and ample than prior to the intercurrent inhibition§ (fig. 3).The tonus also returns and in some cases becomes clearly greater than priorto the inhibition. This after-increase of the knee-jerk takes place when,during the whole period of inhibition, the leg is by mechanical supportprevented from drooping, and thus the passive stretch of the vasto-crureusis avoided during the inhibition. The after-increase also occurs when theelicitation of the knee-jerk is c
. On Innervation of Antagonistic Muscles. Ninth Spinal Induction . ickly becomes again elicitable, and soonis more brisk and ample than prior to the intercurrent inhibition§ (fig. 3).The tonus also returns and in some cases becomes clearly greater than priorto the inhibition. This after-increase of the knee-jerk takes place when,during the whole period of inhibition, the leg is by mechanical supportprevented from drooping, and thus the passive stretch of the vasto-crureusis avoided during the inhibition. The after-increase also occurs when theelicitation of the knee-jerk is completely remitted during the whole periodof the inhibition. The after-increase is not therefore due to any continuance * Sherrington, * Brit. Assoc. Eeports, 1904, Address to Section L t Ihid. I Exner, * Pfliigers Archiv,^ Yol. 28. § * Eoy. Sec. Proc., B, vol. 76, p. 161. 484 Prof. C S. Sherrington. [Jan. 31, of the action of exciting stimuli during the period of inhibition. It is a*successive spinal induction following upon inhibition, just as in theinstance previously Fig. 3.—Knee-jerks. The knee-jerks were elicited by taps of equal intensity delivered at intervalssignalled by a metronome. During the time marked by the signal the afferent nerve of aflexor muscle of the knee was weakly faradised. This inhibitory stimulus depressed theknee-jerk. After the inhibitory stimulus was discontinued the jerks increased to beyond theiramplitude prior to the inhibition ; this increase is accompanied by a tonic after-action followingeach jerk. Time registered above in seconds. In the scratch-reflex/ after its inhibition by the crossed extension-reflex,or the homonymous flexion-reflex, a similar after-exaltation is sometimesseen. Fig. 4 exemplifies such an occurrence. But the time of interruptionof the reflex has usually in my records been too short to allow much scopefor the development of successive spinal induction, and the quick tiring ofthe scratch-reflex under electric e
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