DIGESTION AND FOOD. 25 



the stomach, stimulates the mucous coat to throw out suf- 

 ficient gastric juice to dissolve it. In neither case is fluid 

 enough given out at once to mix with an entire meal. But 

 as we see it in the mouih, so in the stomach it is given out, 

 part by part, as often as a portion of food arrives and de- 

 mands it. Even this small quantity is not poured out with a 

 gush, but it oozes out slowly, as the perspiration oozes from 

 the forehead, until there be enough to mix with the new 

 morsel that is swallowed. This is not a rapid process; it 

 takes a few moments to wet each morsel. If, then, we swal- 

 low more rapidly than the morsels can be wet with the juice, 

 they must accumulate, and wait for the fluid to come. 



39. This secretion and flow of gastric juice commences 

 as soon as any food reaches the stomach, and then continues 

 to flow, if stimulation by new morsels is successively repeat- 

 ed. But this secretion is not without end. This liquid 

 cannot, like the saliva in the mouth, be made to flow as long 

 as we wish. There is a limit to the gastric juice which will 

 be secreted at any one time. Dr. Beaumont says, " When 

 the alimentary matter is received into the stomach, this fluid 

 then begins to exude from its proper vessels, and increases 

 in proportion to the quantity of aliment naturally required 

 and received." * It flows, then, not in proportion to the food 

 which we may happen to eat, but in proportion to the quan- 

 tity of nutriment which the body needs. When, therefore, 

 so much of this juice is poured out as will dissolve what food 

 we need at any one time, it will stop, and the mucous mem- 

 brane will give no more. And, as only a definite proportion 

 of aliment can be digested in a given quantity of this fluid, 

 if more be eaten than this quantity can dissolve, that is, if 

 more food be swallowed than the body needs to supply its 

 waste, the excess either remains in the stomach undigested, 

 and is there a cause of intense pain and oppression, or it is 

 thrown out and onward, in a crude state, to disturb the 

 organs beyond. 



* Observations, p. 85. 

 3 



