ACTION OF THE STOMACH. 331 



440. In regard to the cause of the sense of Hunger, many different theories 

 have been propounded. The following positions may be considered as well 

 ascertained. The sense of Hunger, although referred to the stomach, is 

 governed by the condition of the system at large ; being increased, when the 

 demand for Nutrition is greater than that which the Blood can supply ; and 

 being diminished, when such an addition is made to the nutritive ingredients 

 contained in the latter, as renders it adequate for this purpose, even though 

 this addition be not made through the introduction of food in the usual man- 

 ner. It is, however, immediately dependent on some condition of the stomach 

 itself; for it is abated, if not arrested, by section of the eighth pair of nerves 

 ( 199) ; and it may be temporarily alleviated by introducing into its cavity 

 matter which is not alimentary, but which causes pressure on its walls, and 

 probably a flow of gastric juice. It may subside instantaneously under the 

 influence of mental emotion, or of other strong impressions on the nervous 

 system. It is easy to prove that many of the causes which have been assigned 

 for it, are but little, or not at all, concerned in the production of the sensation. 

 Thus, mere emptiness of the stomach does not produce it ; since, if the pre- 

 vious meal have been sufficient, the food passes from its cavity some time 

 before a renewal of hunger is felt. It cannot be due to the action of the gastric 

 fluid upon the coats of the stomach themselves ; since this fluid is not poured 

 into the stomach, except when the production of it is stimulated by the irrita- 

 tion of its secreting follicles. By Dr. Beaumont it is thought, that the distension 

 of these follicles by the secreted fluid is the proximate cause of hunger ; but 

 there is no more reason to believe that the secretion of Gastric fluid is accumu- 

 lating during the intervals when it is not required, than there is in regard to 

 Saliva, the Lachrymal fluid, or any other secretions which are occasionally 

 poured out in large quantities under the influence of a particular stimulus; 

 and, moreover, it is difficult to imagine how mental emotion, or any impression 

 on the nervous system alone (which is able, as is well known, to dissipate the 

 keenest appetite in a moment), can relieve such distension. 



441. It may, perhaps, be a more probable supposition, that there is a cer- 

 tain condition of the Capillary circulation in the Stomach, which is prepara- 

 tory to the secretion, and which is excited by the influence of the Sympathetic 

 nerves, that communicate (as it were) the wants of the general system. This 

 condition may be easily imagined to be the proximate cause of the sensation 

 of hunger, by acting on the Par Vagum. When food is introduced into the 

 stomach, the act of secretion is directly excited; the capillary vessels are 

 gradually unloaded; and the immediate cause of the impression on the par 

 vagum is withdrawn. By the conversion of the alimentary matter into mate- 

 rials fit for the nutrition of the system, the remote demand also is satisfied ; 

 and thus it is, that the condition of the stomach just referred to, is permanently 

 relieved by the ingestion of substances that can serve as food. But if the 

 ingested matter be not of a kind capable of solution and assimilation, the feel- 

 ing of hunger is only temporarily relieved, and soon returns in greater force 

 than before. The theory here given seems reconcilable with all that has been 

 said of the conditions of the sense of hunger ; and particularly with what is 



ness of either the existence or the state of the stomach during health. In accordance 

 with this, Dr. Beaumont's experiments prove, that extensive erythematic inflammation of 

 the mucous coat of the stomach was of frequent occurrence in St. Martin, after excesses 

 in eating, and especially in drinking, even when no marked general symptom was 

 present to indicate its existence. Occasionally, febrile heat, nausea, headache, and 

 thirst were complained ot* but not always. Had St. Martin's stomach, and its inflamed 

 patches, not been visible to the eye, he too might have been pleased that his temporary 

 excesses did him no harm; but, when they presented themselves in such legible cha- 

 racters, that Dr. Beaumont could not miss seeing them, argument and supposition were 

 at an end, and the broad fact could not be denied." 



