196 DIGESTION. 



observed by Magendie in dogs, in his experiments on the 

 uses of the epiglottis in deglutition. 1 Magendie believed 

 that this act was sufficient to protect the air-passages from 

 the entrance of all substances, liquid as well as solid. The 

 experiment of Longet, cited above, shows that this is not the 

 case; for if the movements of ascension of the larynx be 

 interfered with, liquids and moist articles are liable to find 

 their way into its cavity. The conclusions arrived at by 

 Magendie concerning the importance of the epiglottis in 

 deglutition have not been absolutely verified by the experi- 

 ments of others, nor are they carried out by observations on 

 the human subject; for when this part is entirely absent, 

 liquids are liable to penetrate the larynx. 



The experiments of Longet with regard to the impor- 

 tance of the closure of the glottis itself in deglutition are 

 very interesting. 2 This observer divided, first of all, the re- 

 current laryngeal nerves and the branch of the superior 

 laryngeal going to the crico-thyroid muscle, thus paralyzing 

 all the intrinsic muscles of the larynx. ISTothwithstanding 

 this, he found the occlusion of the glottis complete with 

 every act of deglutition, and demonstrated that this was due 

 to the powerful contraction of the inferior constrictors of the 

 pharynx, drawing together the sides of the larynx. In two 

 sheep and two dogs, after having removed a portion of the 

 trachea, he kept the glottis open by the introduction from be- 

 low of a dissecting forceps, and found that notwithstanding 

 the impossibility of closing the glottis, neither solids nor 

 liquids penetrated the trachea in swallowing. These ex- 

 periments show conclusively that although the glottis is 

 accurately closed during deglutition, this is not absolutely 



1 MAGENDIE, Memoir e sur V usage de VEpiglotte dans la Deglutition, Paris, 

 1813, p. 3. 



2 LONGET, Traite de Physiologic, Paris, 1861, tome i., p. ,108, and Recherches 

 Experimentales sur les Fonctions de PEpiglotte et sur les Agents de Pocdusion de la 

 Glotte dans la Deglutition, le Vomissemcnt et la Rumination. Archives Generates 

 de Mededne, Paris, 1841, 3me Serie, tome xii., p. 417 et seq. 



