4M 



On Vomiting, 



and the no less prompt action of the oesophagus upon the 

 stomach. 



This agitation of the oesophagus is not confined to the ahmen- 

 tary canal, properly speaking ; the branches of the par vagum, 

 and of the great intercostals which cross around it, must partici- 

 pate in this movement. 



We observed above that as long as the stomach of dogs labour- 

 ing under an emetic was out of the body, no vomiting took 

 place, but only nausea ; but when the stomach was restored to 

 its place, vomiting immediately followed. The next point to 

 be determined was, if the action of the abdominal muscles be 

 absolutely necessary to produce vomiting, as was the opinion of 

 Chirac and his adherents. These muscles were removed from a 

 robust dog, and an emetic being injected, he vomited apparently 

 with as much facility as if that operation had not been per- 

 formed, which reduced the covering of the abdomen to the 

 peritoneum, and to a few transverse muscular fibres which it was 

 impossible to remove. M. Magendie made us remark in this 

 case the great tension of the linea alba, during the nausea and 

 vomiting 5 and we conceive that this species of cord stretched 

 along the abdomen may be sufficient to keep the intestines in 

 their places, and to prevent them from escaping from the ener- 

 getic action of the diaphragm, which in some of the experi- 

 ments even tore the peritoneum in several places. 



One of us had made an analogous observation, but without 

 drawing the same consequence, upon a soldier, the muscles of 

 whose abdomen had been removed or destroyed by the action of 

 a large cannon ball; so that after his cure the stomach in all its 

 positions might be seen through the transparent peritoneum. 

 This soldier, during his cure, was frequently troubled with 

 vomiting, to which the abdominal muscles could not contribute, 

 as they were wanting altogether; yet he vomited with as little 

 difficulty as before his wound. 



The experiment above related, which was first thought of by 

 M. Magendie, proves that it is the diaphragm which acts with 

 the greatest efficacy in vomiting, and that the abdominal muscles 

 serve scarcely any other purpose than to confine the viscera float- 

 ing in the abdomen, and to oblige them to re-act in a contrary 

 direction. But when the action of the diaphragm is carried too; 

 far, and when the inspirations are too profound and too long, 

 then instead of vomiting we have alvine evacuations, doubtless 

 because the oesophagus is too much pressed upon by the dia- 

 phragm to give free passage to the substances wliich endeavour 

 to escape from the stomach. 



When, on the contrary, the diaphragm can only act feebly, 

 and solely for the maintenance of respiration, as happens when 



