SCIENTIFIC PROCEEDINGS 



Abstracts of Communications. 



Seventy-fifth meeting. 



College of Physicians and Surgeons, April ig, igi6. 

 President Jacques Loeb in the chair. 



67 (1131). 



An active expiratory muscle in the chicken which is inhibited by 

 stimulation of the central end of the vagus. A demonstration. 



By A. L. Meyer and S. J. Meltzer. 



[From the Department of Physiology and Pharmacology of the 

 Rockefeller Institute for Medical Research.] 



In mammals expiration is passive under ordinary conditions. 

 It is only under abnormal conditions that certain muscles become 

 active during the expiratory phase of respiration. At the last 

 meeting of the Federation of American Societies for Experimental 

 Biology 1 we made the statement that in the fowl normal expiration 

 is active. We wish to demonstrate the truth of this statement by 

 a graphic method. We have found that the innermost of the ab- 

 dominal muscles in the chicken when carefully isolated contracts 

 regularly with each expiration. When the contractions of this 

 muscle are recorded simultaneously with the movements of the 

 thorax it will be observed that the muscle contracts during ex- 

 piration and suddenly relaxes during the onset of inspiration. 



The literature concerning the effect upon the respiration of 

 stimulation of the central end of the vagus in mammals is very 

 extensive and full of conflicting opinion as to the nature of this 

 effect. In fowls stimulation of the central end of the vagus causes 

 an unmistakable inhibition of the contractions of this muscle. 

 When the movements of the thorax and the contractions of the 



1 American Jour, of Physiology (Proceedings), 1916, 40 (No. 1), 127. 



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