1912.] Induced by Concurrent Excitation and Inhibition. 291 



(a) Oscillations Resulting from tv;o Opposed Stimuli. 

 In the case of the simultaneous stimulation of the two afferent nerves, 

 excitatory and inhibitory, various relative strengths of the opposed stimuli 

 were employed. In an early experiment, the inhibitory stimulus being 

 strong enough almost to prevent contraction, slight oscillations were 

 produced by combined stimulation, as is shown in fig. 1.* The figure 

 shows first the contraction from the excitatory stimulus acting alone, then 

 the response resulting from an excitatory stimulus of the same strength 



Fig. 1. — Vastocrureus preparation. Time-marker below records intervals of ^ second. 

 (Harvard.) 



opposed by inhibition two minutes later. The oscillations in this response 

 occur at a rate of about seven a second. 



In another animal with marked decerebrate rigidity, the opposed stimuli 

 were carefully adjusted until, when applied simultaneously, no immediate 

 change in the length of the muscle occurred. Almost immediately, 



* In this and all subsequent figures, ascent of the myograph line means contraction of 

 the muscle. The excitatory stimulus is marked by a rite in the upper signal line (E). 

 The inhibitory stimulus is marked by zfall in the lower signal line (I). The strength 

 of stimulus in Martin units is indicated by figures on the records. All read from left to 

 right. 



