Reflex Rhythm Induced by Excitation and Inhibition. 289 



bility that could not be overlooked if the phenomenon occurred alone in 

 the decerebrate preparation. 



14. A possible explanation of the conditioning of rhythmic activity is 

 given in the present paper in a contracted form. It has already been 

 presented, along with a more detailed account of these experiments, to the 

 University of Edinburgh. 



Reflex Rhythm Induced by Concurrent Excitation and Inhibition. 

 By Alexander Forbes, M.A, M.D., Harvard. 



(Communicated by Prof. C. S. Sherrington, F.R.S. Received April 11, — Read 

 May 16, 1912.) 



(From the Laboratories of Physiology in the Harvard Medical School and in the 

 University of Liverpool.) 



CONTENTS. 



PAGE. 



I. Introduction 289 



II. Method 290 



III. Observations 290 



(a) Oscillations resulting from Two Opposed Stimuli 291 



(6) Oscillations resulting from a Single Stimulus 294 



IV. Conclusion 297 



I. Introduction. 



In a paper on " Antagonism between Reflex Inhibition and Reflex 

 Excitation,"* Sherrington has shown that the combined effects of excitatory 

 and inhibitory stimuli produce a response intermediate between those of the 

 two stimuli acting singly. Prof. Cannon, of Harvard, called my attention to 

 certain minute oscillations which occur in Sherrington's myograph line where 

 it represents the response of muscle to the combined effects of the opposed 

 stimuli,f and suggested that these might have an important significance. 

 They might mean that the nerve impulses in breaking through the opposition 

 imposed by inhibition were subjected to a condition analogous to a stream of 

 air passing out from a tube under water.J It seemed possible that just as 

 the air bubbles will be larger and more infrequent if the opening of the tube 



* ' Roy. Soc. Proc.,' B, vol. 80, p. 565.- 



t Cf. also 4 Eoy. Soc. Proc.,' B, vol. 81, p. 258. 



| Cf. Rosenthal, ' Die Atembewegungen und ihre Beziehungen zum Nervus Vagus,' 

 Berlin, 1862. 



