SENSE OF HUNGER SECRETION OP GASTRIC JUICE. 189 



in abundance when the lining membrane is stimulated by 

 the contact of food, especially solid food. Only a limited 

 quantity is secreted at any one time ; and this quantity is 

 just that which is sufficient to dissolve food enough for the 

 supply of the natural wants of the system. The contact of 

 any solid substances with the interior of the stomach, is suffi- 

 cient to produce a flow of this fluid into its cavity ; but the 

 secretion soon ceases if the substance be not of an alimentary 

 nature. 



205. The sense of hunger appears due to the distension of 

 the blood-vessels of the stomach, which takes place in pre- 

 paration for the secretion of the gastric fluid. This deter- 

 mination of blood towards the stomach seems to occur when- 

 ever the body needs a fresh supply of nourishment ; and it 

 ceases as soon as a sufficient amount of gastric fluid has been 

 drawn off. Hence it is, that hunger is relieved by eating ; 

 and hence it is, also, that hunger is for a time relieved by 

 taking solid substances into the stomach, even though they 

 contain no nourishing matter. It is from having experienced 

 this, that savage nations are in the habit of mixing indiges- 

 tible solid matter with the fluids that sometimes constitute 

 their principal articles of food. Thus the Kamschatdales mix 

 earth or saw-dust with the train-oil on which alone they are 

 frequently reduced to live ; and the Veddahs, or wild hunters 

 of Ceylon, mix the pounded fibres of soft or decayed wood 

 with the honey on which they feed when meat is not to be 

 had. One of them being asked the reason of the practice, 

 replied, " I cannot tell you, but I know that the belly must 

 be filled." It has been found by experiment, that soups and 

 other forms of liquid aliment are not alone fit for the support 

 of the system, even though they may contain a large amount 

 of nutritious matter ; and the medical man well knows, that 

 many persons have stomachs too weak and irritable to retain 

 " slops" (as they are commonly termed), who can yet digest 

 solid food of a simple kind. All these instances show, that 

 the contact of a solid substance with the walls of the stomach, 

 is the proper stimulus or excitement to the secretion of the 

 gastric fluid. 



206. This fluid, when poured upon the food, is thoroughly 

 mixed-up with it by a peculiar movement of the walls of the 

 stomach, which is continually bringing fresh portions of the 



