1913.] arising from Rivalry of Antagonistic Reflexes. 261 



IV. Summary of Conclusions. 



It is shown that taking an afferent nerve which produces steady reflex 

 excitation of the muscle, and another which produces steady reflex inhibition 

 of the muscle, it is possible by stimulating both nerves concurrently to obtain 

 regularly rhythmic contractions and relaxations of each member of a pair 

 of symmetrical muscles, the phases being reciprocal in the two. To do this 

 requires certain somewhat narrowly adjusted proportions of strength of the 

 two paired stimuli. The stimuli are both of them continuous, in the sense 

 that they are faradic and of a frequency (about 40 per second) much above 

 and bearing no causal relation to the rhythmic reflex produced. In the 

 rhythmic reflex the right and left muscles each contract and relax alternately 

 and move reciprocally, the contracting phase of right muscle being syn- 

 chronous with the relaxing phase of left, and conversely. This rhythmic 

 reflex is shown clearly to be reflex stepping. In short, under the rivalry 

 of the two opposed and so to say equipoised continuous stimulations th 

 limbs exhibit reflex walking. With certain other paired intensities of 

 stimulation of the two antagonistic afferent nerves, it can be arranged that 

 only one muscle of the pair shall step — the left muscle if the right nerve 

 stimulus be the stronger, and conversely. During this unilateral walking or 

 running the other leg is kept steadily flexed by the reflex, i.e. the extensor 

 muscles are kept steadily inhibited. 



