MOVEMENTS OF THE STOMACH. 233 



unresisting bag through the oesophagus ; and that, under very 

 abnormal circumstances, the stomach, by itself, cannot or rather 

 does not expel its contents. They by no means show that in 

 ordinary vomiting the stomach is passive ; and, on the other 

 hand, there are good reasons for believing the contrary. 



It is true that facts are wanting to demonstrate with cer- 

 tainty this action of the stomach in vomiting ; but some of the 

 cases of fistulous opening into the organ appear to support the 

 belief that it does take place ; l and the analogy of the case of 

 the stomach with that of the other hollow viscera, as the rec- 

 tum and bladder, may be also cited in confirmation. 



Besides the influence which it may thus have by its contrac- 

 tion, the stomach also essentially contributes to the act of 

 vomiting, by the contraction of its pyloric orifice at the same 

 time that the oblique fibres around the cardiac orifice are re- 

 laxed. For, until the relaxation of these fibres, no vomiting 

 can ensue ; when contracted, they can as well resist all the 

 force of the contracting abdominal and other muscles, as the 

 muscles by which the glottis is closed can resist the same force 

 in the act of straining. Doubtless we may refer many of the 

 acts of retching and ineffectual attempts to vomit, to the want 

 of concord between the relaxation of these muscles and the con- 

 traction of the others. 



The muscles with which the stomach co-operates in contrac- 

 tion during vomiting, are chiefly and primarily those of the 

 abdomen ; the diaphragm also acts, but not as the muscles of 

 the abdominal walls do. They contract and compress the 

 stomach more and more towards the back and upper parts of 

 the diaphragm ; and the diaphragm (which is usually drawn 

 down in the deep inspiration that precedes each act of vomit- 

 ing) holds itself fixed in contraction, and presents an unyield- 

 ing surface against which the stomach may be pressed. It is 

 enabled to act thus, and probably only thus, because the in- 

 spiration which precedes the act of vomiting is terminated by 

 the closure of the glottis; after which the diaphragm can 

 neither descend further, except by expanding the air in the 

 lungs, nor, except by compressing the air, ascend again until, 

 the act of vomiting having ceased, the glottis is opened again 

 (see diagram, p. 181 ; see also p. 183). 



Some persons possess the power of vomiting at will, without 

 applying any undue irritation to the'stomach, but simply by a 

 voluntary effort, It seems also, that this piower may be ac- 



1 A collodion of cases of fistulous communication with the stomach, 

 through the abdominal parietes, has been given by Dr. Murchison in 

 vol, $lj of the Medico-Chirurgical Transactions, 



