principally to the secretion of the stomach. Whether the digestive 

 faculty depends upon communication with the brain, any furthet 

 than the secretions of the stomach are necessary to digestion, 

 remains to be determined. 



29. It is necessary further to inquire what other relations 

 the stomach has with contiguous or distant parts. It is to be 

 examined whether its function is in any way dependent upon the 

 the liver, the spleen, the pancreas, &c. In this examination the 

 division of the living fabric is to be observed. Of each severally 

 it is to be asked, does the stomach obtain vital properties from the 

 liver, the spleen, the pancreas, &c. ? or has it with either a chyuii- 

 cal, a mechanical, or a mixed relation 1 ? 



30. A perfect physiology of the stomach would instruct us 

 of its relations as an agent, with respect to other organs, as well 

 as concerning its own dependences. 



31. It has been indicated in the beginning of this article 

 that in this way it is related with the brain. It has been remarked 

 that the function of digestion is neither required nor manifested 

 during ftetal life; that it takes place afterwards under circum- 

 stances (those of ingeslion) in which the primary operation of an 

 occasional cause must be upon the stomach and its properties. 

 We have therefore to decide whether the stomach derives proper- 

 ties from the brain directly necessary to digestion, of an habitual 

 or occasional kind; whether such an habitual communication 

 takes place as that which has been almost proved with regard to 

 the cerebral properties which concur in gastric secretion ; or 

 whether the function, being occasional, the brain furnishes pro- 

 perties for the purpose of digestion in consequence only of an 

 operation of properties of the stomach upon those of the brain, 

 the series of which might be expressed in this order, 1st, inherent 

 properties of the stomach, produced by its assimilating life, affected 

 by the presence of food; 2nd, properties of the brain, affected by 

 relation with those of the stomach; 3rd, the result of this latter 

 affection, a re-action of properties of the brain upon those of the 

 stomach, contributing towards the process of digestion. This 

 point cannot at present be decided, because we stand in need of 

 facts to prove eveu that the digestive function is dependent upon 

 the brain. 



32. But we are not without examples that a series of opera- 

 tions of the above kind does occur in other cases, where the oc- 

 casional relation is exhibited. Thus a substance violently emetic 

 produces vomiting so speedily as to preclude the supposition of 

 its having reached the brain by the tedious course of absorption: 

 properties either of this substance, or properties of the stomach 

 modified by those of this substance, are propagated to the brain; 

 a re -agency of the properties of the brain occurs, the secretions of 

 the stomach, which arc traced to a dependence upon the brain, are 

 increased or modified, or both; the sensations of the stomach are 

 also produced, and, finally, vomiting happens, by a participation 

 iu the disturbance on the part of the diaphragm and abdominal 



