Dr. Marshall Hall on the Act of Vomiting. 389 



It is obvious that, if vomiting were effected by a contraction 

 of the diaphragm, it must be attended by inspiration. If this 

 were the case, the fluids ejected from the stomach would be 

 drawn into the larynx, and induce great irritation, events 

 which are not observed. These events are, indeed, effectually 

 prevented by an accurate closure of the larynx, a fact observed 

 in an actual experiment by M. Majendie, who makes the 

 following observation : — *' Dans le vomissement, au moment 

 oil les matieres vomies traversent la pharynx, la glotte se 

 ferme tres-exactement*." It is astonishing that this obser- 

 vation did not lead its acute author to see that, under such 

 circumstances, a contraction of the diaphragm, unless the 

 thorax followed precisely pari passu, was impossible. 



Complete vomiting has been observed, too, in cases in 

 which the stomach had entirely passed through a wound of 

 the diaphragm into the thorax, and in which it could not, 

 consequently, be subjected to the action of that muscle f. In 

 some experiments, vomiting was observed also to take place, 

 although the diaphragm had been paralysed by a division of 

 the phrenic nerves, or its influence subtracted by a division 

 of its anterior attachments J. 



This view of the subject is still further confirmed by facts, 

 which I now proceed to state, which prove that the act of 

 vomiting is an effort, not of inspiration, but of expiration. This 

 is obvious enough, indeed, on a mere observation of the state 

 of the thorax and abdomen during vomiting. The larynx is 

 evidently abruptly and forcibly closed, the thorax drawn down- 

 wards, and the abdomen inwards. 



Such, indeed, appears to me to be the precise nature of the 

 act of vomiting, in ordinary circumstances. The contents of 

 the thorax and abdomen are subjected to the sudden and 

 almost spasmodic contraction of all the muscles of expiration, 

 the larynx being closed so that no air can escape from the 

 chest, and the two cavities being made one by the floating or 

 inert condition of the diaphragm. The mere mechanism of 

 the act of vomiting differs little, therefore, from that of cough- 



* Memoire sur I'Usage de I'Epiplotte dans la Deglutition, p. 3, note. 



t Such a case is mentioned by Wepfer. A similar one was also recently wit- 

 nessed by Dr. Webster and Mr. Hunt. The whole of the stomach was found in the 

 thorax, having passed through a wound of the diaphragm. There was repeated 

 vomiting of a substance resembling coffee-grounds. 



X CEuvres de Car, Legallois, A Paris, 1824, torn, ii. p. 104. . . . . , 



