Dr. Marshall Hall on the Act of Vomiting. 391 



It is not intended to state that the act of vomiting is simply 

 such as I have described. There are many facts which appear 

 to show that the oesophagus is not without its share of influ- 

 ence in this act, and it is plain that the cardiac orifice must be 

 freely opened ; for mere pressure upon the viscera of the ab- 

 domen will not, in ordinary circumstances, evacuate the con^ 

 tents of the stomach. To effect this open state of the cardiac 

 orifice, it is probably necessary that the diaphragm should, 

 indeed, be in a relaxed rather than in a contracted state. 



A singular and interesting fact was noticed by M. Majendie, 

 of which he has not given any explanation. During the state 

 of nausea which preceded the act of vomiting, in some of his 

 experiments, air was drawn into the stomach. I am disposed 

 to think that this effect was produced in the following manner : 

 the larynx being closed preparatorily to the act of vomiting, 

 an attempt at inspiration is made before the effort of expira- 

 tion. In this attempt, air is drawn into the oesophagus, the 

 larynx being impervious, and it is afterwards probably pro- 

 pelled along that canal into the stomach itself It is not 

 improbable, too, that, in some instances of vomiting, in 

 which the action of the abdominal muscles was subtracted *, 

 a similar effort of inspiration has drawn substances from the 

 stomach into the oesophagus, which has eventually expelled 

 them by an inverted action. Neither of these phenomena 

 could result from any action of the diaphragm, and much less 

 from contraction of the abdominal muscles. But it is easy, 

 by closing the larynx and attempting to inspire, to draw air 

 into the oesophagus. A similar act, if very forcible, might 

 draw a portion of the contents of the stomach through the 

 cardiac orifice. 



Such, then, appears to be the nature of the act of vomiting. 

 How different is this act from one in which the diaphragm 

 does, indeed, contract suddenly, under similar circumstances of 

 closure of the larynx, — viz. singultus : the action of the dia- 

 phragm being an effort of inspiration, air is apt to be drawn 

 into the oesophagus with considerable noise; and there is 

 occasionally pain, not only about the insertions of the dia- 

 phragm, but about the closed larynx. 



* CEuvres de Legallois; torn ii. p. 105. 



