228 DIGESTIVE SYSTEM. 



of fluid is completed, the larynx resumes its natural position; 

 but some drops of the fluid always remain on the back of the 

 tongue, and, uniting together, flow into the oesophagus; 

 these would inevitably fall into the larynx but far its mem- 

 branous lid (the epiglottis). Clinical observations and the 

 results of experiments, however, often appear contradictory 

 on this point ; since we find that sometimes a fit of coughing, 

 and at others, no disturbance at all, will follow the degluti- 

 tion of a fluid in invnlids or animals who have been deprived 

 of their epiglottis (Magendie, Longet). The varying nature 

 of these results is easily explained. In man, the epiglottis 

 may be destroyed by so many different causes (wounds, 

 syphilitic erosions) that no two cases can be compared, and 

 one person will suffer no inconvenience, while in another 

 alarming symptoms will follow the deglutition of a fluid. 

 The different results produced in animals by the deglutition 

 of fluids, after the epiglottis has been carefully removed, is 

 explained by the fact that, whenever the animal is calm after 

 deglutition, no disturbance follows, while serious conse- 

 quences ensue if it is agitated in any way. Schiff has demon- 

 strated that, when the deglutition of fluids is apparently fin- 

 ished, the accumulation of drops remaining on the tongue, 

 which descends to the glosso-epiglottal ligaments, gives rise 

 to a second series of movements of deglutition, repeated two 

 or three times, until not a drop of the fluid remains. Now, 

 if an animal be disturbed while drinking, in however slight a 

 degree (as, for instance a dog may be prevented from licking 

 himself, after swallowing a bowlful of milk) this secondary 

 deglutition does not take place, and if the epiglottis have 

 been removed, the drops ot fluid remaining on the tongue, 

 may be introduced into the larynx, and occasion coughing. 

 In short, entire excision of the epiglottis in the dog, does 

 not interfere with the deglutition of fluids, if only that sub- 

 sequent deglutition takes place, which serves to rid the isth- 

 mus of the fauces of those fluid particles which still adhere 

 to it. 



Though solid or liquid particles of food sometimes find 

 their way into the larynx, it rarely happens that they pene- 

 trate into the trachea: as soon as they come into contact 

 with the mucous membrane of the vestibule of the larynx, 

 the peculiar sensibility which the superior laryngeal nerve 

 imparts to this region is excited, giving rise to the phenom- 

 enon of coughing, by means of which these particles are 

 instantly expelled. The exquisite sensibility of the vestibule 



