GASTRIC JUICE, AND STOMACH DIGESTION. 137 



sutures. The animal may be kept perfectly quiet, during the ope- 

 ration, by the administration of ether or chloroform. In a few- 

 days the ligatures come away, the wounded peritoneal surfaces are 

 united with each other, and the canula is retained in a permanent 

 gastric fistula ; being prevented by its flaring extremities both from 

 falling out of the abdomen and from being accidentally pushed into 

 the stomach. It is closed externally by a cork, which may be with- 

 drawn at pleasure, and the contents of the stomach withdrawn for 

 examination. 



Experiments conducted in this manner confirm, in the main, the 

 results obtained by Dr. Beaumont. Observations of this kind are 

 in some respects, indeed, more satisfactory when made upon the 

 lower animals, than upon the human subject ; since animals are 

 entirely under the control of the experimenter, and all sources of 

 deception or mistake are avoided, while the investigation is, at the 

 same time, greatly facilitated by the simple character of their food. 



The gastric juice, like the saliva, is secreted in considerable 

 quantity only under the stimulus of recently ingested food. Dr/ 

 Beaumont states that_it is entirely absent during the intervals of^ 

 digestion ; and that the stomach at that time contains no acid fluid, 

 but only a little neutral or alkaline mucus. He was able to obtain 

 a sufficient quantity of gastric juice for examination, by gently irri- 

 tating the mucous membrane with a gum-elastic catheter, or the end 

 of a glass rod, and by collecting the secretion as it ran in drops 

 from the fistula. On the introduction of food, he found that the 

 mucous membrane became turgid and reddened, a clear acid fluid 

 collected everywhere in drops underneath the layer of mucus lin- 

 ing the walls of the stomach, and was soon poured out abundantly 

 into its cavity. We have found, however, that the rule laid down 

 by Dr. Beaumont in this respect, though correct in the main, is not 

 invariable. The truth is, the irritability of the gastric mucous 

 membrane, and the readiness with which the flow of gastric juice 

 may be excited, varies considerably in different animals ; even in 

 those belonging to the same species. In experimenting with gastric 

 fistula? on different dogs, for example, we have found in one instance, 

 like Dr. Beaumont, that the gastric juice was always entirely absent 

 in the intervals of digestion ; the mucous membrane then present- 

 ing invariably either a neutral or slightly alkaline reaction. In 

 this animal, which was a perfectly healthy one, the secretion could 

 not be excited by any artificial means, such as glass rods, metallic 

 catheters, and the like; but only by the natural stimulus of ingested 



