2GG Dr. Marshall Hall on the 



the reach of being compressed by the contractions of the 

 diaphragm, and as this contraction completely defended it 

 from the influence of the abdominal muscles, it is clear that, 

 in this case, vomiting must have occurred independently of 

 compression, either of the diaphragm or of the abdominal 

 muscles. This fact, worth a thousand experiments, com- 

 pletely decides the question, that vomiting may be produced by 

 the action of the stomach itself, unassisted by any external 

 compressing force, notwithstanding what Le Gallois and late 

 physiologists have said to the contrary.'* 



The authors of the report do not appear to have seen the 

 paper f which I published in the number of this Journal for 

 April to July, 1828 ; the object of which was first, to expose 

 the fallacy, both of that view of the nature of the act of vomit- 

 ing, which refers it to a contraction of the stomach itself, and 

 of that other view lately advocated by M. Magendie, which 

 refers this act to the simultaneous contraction of the dia- 

 phragm and abdominal muscles ; and, secondly, to propose a 

 new view of this disputed question. As this last view has 

 never been controverted as it has, on the other hand, been 

 generally admitted and as it alone explains the various diffi- 

 culties which beset each or both of the other two it may not 

 be amiss to reproduce its broad outlines here, in connexion 

 with the interesting case of Dr. Graves and Dr. Stokes. They 

 are these : 



1. During the act of vomiting, the larynx is closed ; 



2. The diaphragm, and its various apertures, are relaxed ; 

 and, 



3. All the muscles of expiration are called into action ; but, 



4. Actual expiration being prevented by the closure of the 

 larynx, the force of the effort is expended upon the stomach, 

 the cardia being open from the relaxed condition of the dia- 

 phragm, and vomiting is effected. 



It is plain, from this view of the subject, that the thorax and 

 abdomen become one cavity, as it were, the diaphragm lying 

 loose and inert between them. It is also obvious, that it is 



* Pp. 8587. 



t In this Paper I have referred to cases similar to that given by the 

 authors of the Report. 



