THE Ml .1 II \\'l-\l- i.i :>i'. 



of tone of the sphincter has been observed to be responsible I nal 



regurgitation of sonu of tl" gastric contents into the esopl 

 level of the hearl or even to the base of the neck Tl e pr< 

 gastric contents in the esophagus starts a peristaltic \ vhich ; 



the material back again into the stomach. This p 



in the absei if any other phases of the deglutition pro 



thai ii has been excited by the presence of the material in tl 

 itself, and belongs, therefore, to the lower order of peristaltic 

 seen in the intestines bul nol in the upper half of the esophag R gur- 

 gitation iif food into the esophagus occurs only when the ii ' trie 

 pressure is fairly high. It maj last for a period of from twenty to th 

 minutes after the meal is taken, and disappears when the tonus 

 sphincter becomes increased as a resull of the presence in tl trie 

 contents of free hydrochloric acid. 



Much information lias been secured by listening with a stethi i to 

 the sun mis caused by swallowing and by observing with the x-n 

 shadows produced along the course of the esophagus when food imp 

 nated with bismuth subnitrate is taken. When a solid bolus al- 



lowed only one sound is usually heard, hut with liquid food th< 

 two, one al the upper end, due to the rush of the fluid and air, and 

 the other at the lower end (heard over the epigastrium . four or six 

 seconds later, due to the arrival lure of the peristaltic wave with the 

 accompanying opening of the cardiac sphincter and tl • 

 fluid and air into the stomach. Sometimes, when the person is in 

 horizontal position, this second sound may be broken up inti eral, 

 indicating that, unassisted by gravity, the fluid does no1 so readily p 

 through the sphincter. The x-ray shadows yield results in conformity 

 with the above. After Bwallowing milk and bismuth, i mple, the 



shadow falls quickly to the lower end of the esophagus and then pas 

 slowly into the stomach. When the passage of a solid bolus is 

 by the x-ray method, its rate of descent will he found to depend 



whether "i- not it is well lubricated with saliva: if not so, it in. 



long as fifteen minutes to reach the stomach; if moist, bul 

 to eighteen seconds. 



Vomitiin; 



Vomiting is usually preceded by a feeling of sickni 

 is initialed h> a very active secretion of saliva. The . mixed with 



air. accumulates to a considerable extent at the I" 



gUS, which it distends. A forced inspiration is now made, during the 



tirst stage of which the glottis is op. thai tl i 



bul later the glottis closes so thai the inspired aii the 



