CHAP. XXIV.] VOMITING. 2 1 1 



these portions of the solid aliments which are absorbed by the 

 stomach. Drinks, as water and various other liquid s, fermented 

 or not, are, doubtless, likewise in great part absorbed in the same 

 way. All other kinds of food, and such remaining portions of the 

 azotised or liquid aliments as have escaped absorption by the 

 stomach, after having undergone to a certain extent maceration 

 in it, are pushed onwards into other parts of the digestive tube 

 there to undergo further changes to fit them for being absorbed. 



Eructation and Vomiting. As there can be no doubt that the 

 movements of the stomach are capable of pushing on the food 

 towards the intestinal canal, it appears prima facie extremely 

 probable that the same muscular force may cause it to evacuate 

 its contents through the oesophagus, if there be any obstacle to 

 their downward passage, too strong to be overcome.* The mus- 

 cular coat of the stomach, pressing by its passive contraction upon 

 its contents, will cause them to pass in that direction which offers 

 the least resistance. Now, in a state of health, the food, in order 

 to return by the oesophagus, must not only overcome the passive 

 contraction of the muscular coat of that tube, but it must also 

 ascend against gravity. Moreover, the action of the fibres of the 

 splenic extremity of the stomach favours the passage of the food 

 towards the pylorus. Hence, not only is there least resistance at 

 the pylorus, but there is likewise a vis a tergo, which favours the 

 propulsion of the food in that direction. 



When, however, air accumulates at the cardia in such quantity 

 as to distend that portion of the stomach, it opens the oesophagus 

 by its expansile force, and from its lightness rushes up the oesopha- 

 gus, carrying with it sometimes liquid or solid food. When air is 

 generated in large quantity and with great rapidity, it is wonderful 

 how much may escape in this way ; and large quantities of food may 

 be discharged from the stomach at the same time, solely by the 

 convective force of the large bubbles of air ascending from it. 

 This is eructation it seems due solely to the presence of a large 

 quantity of air in the stomach. 



Vomiting is an act of a more complex character than eructation ; 

 by it solids and liquids may be expelled from the stomach through 

 the oesophagus, even contrary to gravity. We must assume that a 

 necessary condition for the production of the act of vomiting is 

 the existence of obstruction at or near the pyloric portion of the 



* The old and still prevalent notion of an inversion in the action of the 

 stomach is most probably erroneous. The inversion is only apparent, not real. 

 See an able paper by Dr. Brinton on this subject. Lond. Med. Gazette, 1849. 



