1908. | - Innervation of Antagonistic Muscles. 569 
to show no obvious contraction (see figures in previous papers).* (8) The 
muscle, while lying relaxed under the inhibitory influence of the ipselateral 
reflex already in operation, on fairly strong stimulation being then applied 
to the contralateral afferent nerve still remains, in spite of that stimulus, 
relaxed and to all appearance devoid of any contraction (see figures in 
previous papers).f 
The ipselateral afferent arc is therefore the prepotent one: its action 
overpowers that of the contralateral arc. But, as has been shown elsewhere,t 
this prepotence is not inevitable. The influence of the contralateral 
afferent nerve finds clear expression if its stimulation be strong at a time 
when that of the ipselateral is quite weak (fig. 1). Whether the one 
Fia. 1. 
influence or the other is preponderant depends, therefore, in the case of this 
preparation, on the relative intensity of the stimuli applied to the two 
antagonistic nerves respectively. This reversibility of the sense of the 
reaction seemed to me to indicate the preparation as a favourable one on 
which to test the nature of the antagonism. The more so as in it both the 
excitatory reflex and the inhibitory reflex are capable of being graded 
* ‘Roy. Soc. Proc.,’ B, vol. 76, p. 277. 
+ Eg., ‘Brit. Assoc. Rep.,’ Camb., 1904, p. 736. 
t Sherrington, ‘Integrative Action of the Nervous System,’ p. 225. 
