1913.] arising from Rivalry of Antagonistic Reflexes. 255 



but experience points to the necessity of their being not widely unequal, 

 also to the need for closer balance of r. and 1. stimuli for evoking bilateral 

 rhythmic reflex than for evoking a unilateral one. 



Results referred to at the outset of this communication throw some light 

 on this. It was there said that as the intensity of stimulus used for evoking 

 the reciprocal reflex on the muscle pair is progressively increased, the 

 intensity of both ipsilateral inhibition and contralateral contraction increase, 

 but that of the former more rapidly than that of the latter. Synchronous 

 application of r. and 1. stimuli of equal strength produces when the 

 stimuli are strong suppression of contraction both r. and 1. ; but with 

 weak stimuli bilateral contraction, contraction of both muscles, results. The 

 same result is shown by determining the strength of contralateral stimulus 

 required to force its reflex contraction through an already established 

 ipsilateral inhibition. The kind of result then met with is as follows : A 

 preparation where threshold for r. peroneal was 16 - 4 cm., and that for 

 1. peroneal 15 - 2 cm., yielded the figures — 



cm. cm. 

 Inhibition of E. muscle by r. stim. 13 was broken by reflex contract, due to 1. stim. 14 

 » » 12 „ „ 12'5 



„ „ 11 required 1. 10 cm. to break it through. 



» it 10*5 „ 1. 9 „ 



Such results indicate a relation between intensity of stimulus and 

 intensities of ipsilateral and contralateral reflexes such as is sketched in the 

 diagram. The diagram accounts for the 7'elation between the observations of 



J i i \ i i i i I o £ 



Distances of secondary coil. 



