162 FUNCTIONS OF NUTRITION. 



agitation, in a measured quantity of fresh gastric juice at the tempera- 

 ture of 38 C. The liquefied portions were then filtered away, the 

 residue evaporated to dryness, and the quantity of fresh meat remain- 

 ing undissolved thus calculated from the percentage of its solid ingredi- 

 ents. In this way it was found that one gramme of meat had been 

 liquefied by 13.5 grammes of the digestive fluid. We have already 

 seen (p. 129) that a man consumes, in his ordinary daily ration, 453 

 grammes of meat ; which would require for complete digestion a little 

 over 6000 grammes of gastric juice. This agrees very nearly with 

 the estimate of Bidder and Schmidt given above ; and if gastric 

 juice were the only digestive fluid acting on the food, we might 

 accept it as correct. But below the stomach other secretions take 

 part in the digestive process ; and some of them, especially the pan- 

 creatic juice, have a certain action on albuminous matters, and may 

 facilitate considerably their solution in the intestine. For the partial 

 solution of meat, the disintegration of its fibres, and its reduction to 

 a soft, grumous, or semi-fluid consistency, Beaumont found a much 

 smaller quantity of gastric juice sufficient. In one experiment, one 

 gramme of cooked meat was disintegrated by 2.5 grammes, and in 

 another by 1.83 grammes of gastric juice. Its complete solution 

 would of course require a larger quantity. 



These data are insufficient for determining the precise quantity of 

 gastric juice required for digestion. But if we allow sufficient weight 

 to all the observations on this subject, it is evidently very abundant ; 

 and it would not be extravagant to estimate its quantity as at least 

 3000 grammes per day. 



Process of Stomach Digestion. The first effects of the introduction 

 of food into the stomach, according to all observers, are increased vas- 

 cularity of its mucous membrane, a slight elevation of its temperature, 

 and the exudation, in greater or less abundance, of its acid secretion. 

 At the same time the peristaltic movement begins to take place, by 

 the alternate contraction and relaxation of the longitudinal a^nd cir- 

 cular fibres of the muscular coat. This motion is minutely described 

 by Beaumont, who examined it, both by watching the movements of 

 the food through the gastric fistula, and by introducing into the stomach 

 the bulb and stem of a thermometer. According to his observations, 

 the food, after entering the cardiac orifice, is first carried to the left 

 into the fundus of the stomach, thence downward and along the great 

 curvature to the pyloric portion. In this region there was often a 

 constriction, by which the thermometer was gently grasped and drawn, ^ 

 with a twisting motion, toward the pylorus. In a moment or two, it was 

 again released and carried, together with the food, along the small 

 curvature of the organ to its cardiac extremity This circuit was 

 repeated so long as any food remained in the stomach ; but toward 

 the end of digestion it became less active, and the stomach, when com- 

 pletely empty, returned to its ordinary quiescent condition. 



The muscular action of the stomach during digestion in the dog may 



