166 DIGESTION. 



dry, requires for its solution 20 grammes of gastric juice. As the aver- 

 age daily consumption of albuminous matter in man is 130 grammes, 

 this would accordingly require in him the secretion of 2600 grammes 

 of gastric juice per day. Our own observations on the digestibility of 

 fresh meat make the daily requirement still higher. A weighed quantity 

 of fresh lean meat, containing 18 per cent, of water and 22 per cent, of 

 solid ingredients, was cut into small pieces, and digested for ten hours, 

 with frequent agitation, in a measured quantity of fresh gastric juice at 

 the temperature of 38 (100 F.). At the end of that time, the liquefied 

 portions were filtered away, the residue evaporated to dryness, and the 

 quantity of fresh meat remaining undissolved thus calculated from the 

 percentage of its solid ingredients. In this way it was found that one 

 gramme of meat had been liquefied by 13.5 grammes of the digestive 

 fluid; and accordingly the 453 grammes of meat consumed by a man 

 in twenty-four hours would require for complete solution a little over 

 6000 grammes of gastric juice. This agrees very nearly with the esti- 

 mate of Bidder and Schmidt given above. If the gastric juice were the 

 only digestive fluid which acts on the food, we could rely fully 011 the 

 foregoing estimate. But below the stomach other secretions also take 

 part in the digestive process ; and it is possible that some of them, 

 especially the pancreatic juice, have also a certain amount of action 

 upon albuminous matters, and may facilitate considerably their solu- 

 tion in the intestine. For the partial solution of meat, the disintegra- 

 tion of its fibres, and its reduction to a soft, grumous, liquid or semi- 

 liquid consistency, Dr. Beaumont found a much smaller quantity of 

 gastric juice to be sufficient. In one experiment 1 gramme of cooked 

 meat was completely disintegrated in this way by 2.5 grammes, and in 

 another by 1.83 grammes of gastric juice. Its entire solution would of 

 course have required a larger quantity. 



These data are accordingly insufficient for determining the precise 

 quantity of the secretion required for the digestive process. But if we 

 allow sufficient weight to all the observations on this subject, it is evi- 

 dent that the gastric juice is very abundant ; and it would not be an 

 extravagant calculation to estimate its quantity as at least 3000 grammes 

 per clay. 



Physiological Action of the Gastric Juice. From the properties of 

 the gastric juice already ascertained, it is seen to have an energetic 

 action upon the albuminous ingredients of the food. As but few of the 

 alimentary substances, however, habitually taken by either man or 

 animals, consist solely of albuminous matter, the changes which they 

 actully undergo in the stomach become a subject for further investi- 

 gation. 



The first effect of the introduction of food into the stomach, according 

 to all observers, is an increased vascularity of its mucous membrane, a 

 slight elevation of its temperature, and the immediate exudation, in 

 more or less abundant quantity, of its acid secretion. At the same 

 time the stimulus of the ingested food excites the peristaltic movement 



