406 Dr. F. Semon. On the Position of the 



The nature of the question evidently renders it impossible to give 

 absolute proof of the quiescence of the glottis in quiet respiration, in 

 man, but there cannot be the slightest doubt that repetition (under 

 the necessary precautions) of the observations to be detailed hereafter 

 will fully corroborate the statements concerning this point so far 

 made, and for the purposes of the present investigation they may 

 fairly be taken as proven. 



If this then be granted, the question arises whether the quiescent 

 state of the glottis as seen during tranquil respiration is identical 

 with the condition seen after death (the cadaveric position) or 

 whether during both phases of respiration the glottis during life is 

 wider than it is in the dead body. This question is one of funda- 

 mental importance for the present investigation. If it were true, as 

 assumed for instance by Griitzner and Michael Foster, that the width 

 of the glottis during tranquil breathing is identical with the cadaveric 

 position, the larynx would be reduced, so far as its participation in 

 normal respiration is concerned, to the passive role of an air-conduct- 

 ing tube, and would thus be put on a par with the trachea and the 

 bronchi. This position of the vocal cords could be expressive of one 

 of two conditions only, namely, either of a state of complete inaction 

 of the vocal cords (Griitzner), or what practically amounts to the 

 same, of a state of complete equilibrium between the abducting and 

 addncting forces (Foster). In either case there would be no active 

 participation of the larynx in the function of respiration. 



If, on the other hand, Rosenthal's, Vierordt's, and MacKendrick's 

 contention were true, that the glottis is widely open during both phases 

 of quiet respiration, or at any rate wider than after death, it would 

 follow with logical necessity that the state of things seen during life 

 represents neither an equilibrium between the antagonistic adducting 

 and abducting forces, nor a state of inaction of both of them, 

 but that it must necessarily be due to some actual muscular force 

 which would be at work constantly during life. The result of the 

 action of this force being that the glottis is more dilated even during 

 quiet respiration than it is after death, this would obviously seem to 

 signify that its function is to facilitate the act of respiration by allow- 

 ing a freer ingress and egress of air to and from the lungs than would 

 be possible if the vocal cords were either in a state of inaction or of 

 balance of the antagonistic motor forces. The larynx then would not 

 play a mere subordinate part in respiration as commonly supposed and 

 come into action only as an accessory or associate in case of need, that 

 is, during forcible respiration, but would be in a state of permanent 

 activity during life, and those of its muscles which keep the glottis 

 wider open during ordinary respiration than it is after death would, of 

 necessity, belong to the class of regular respiratory muscles and would 

 deserve a more prominent position than has been hitherto accorded to them. 



