136 DIGESTION. 



lateral portion of the diaphragm, into the great pouch of the stomach. 

 After the integument and the pleural and peritoneal surfaces had 

 united and cicatrized, there remained a permanent opening, of about 

 four-fifths of an inch in diameter, leading into the left extremity of 

 the stomach, which was usually closed by a circular valve of pro- 

 truding mucous membrane. This valve could be readily depressed 

 at any time, so as to open the fistula and allow the contents of the 

 stomach to be extracted for examination. 



Dr. Beaumont experimented upon this person at various intervals 

 from the year 1825 to 1832. 1 He established during the course of 

 his examinations the following important facts : First, that the ac- 

 tive agent in digestion is an acid fluid, secreted by the walls of the 

 stomach ; secondly, that this fluid is poured out by the glandular 

 walls of the organ only during digestion, and under the stimulus of 

 the food ; and finally, that it will exert its solvent action upon the 

 food outside the body as well as in the stomach, if kept in glass 

 phials upon a sand bath at the temperature of 100 F. He made 

 also a variety of other interesting investigations as to the effect 

 of various kinds of stimulus on the secretion of the stomach, the 

 rapidity with which the process of digestion takes place, the com- 

 parative digestibility of various kinds of food, &c. &c. 



Since Dr. Beaumont's time it has been ascertained that similar 

 gastric fistulas may be produced at will on some of the lower animals 

 by a simple operation; and the gastric juice has in this way been 

 obtained, usually from the dog, by Blondlot, Schwann, Bernard, 

 Lehmann and others. The simplest and most expeditious mode 

 of doing the operation is the best. An incision should be made 

 through the abdominal parietes in the median line, over the great 

 curvature of the stomach. The anterior wall of the organ is then 

 to be seized with a pair of hooked forceps, drawn out at the external 

 wound, and opened with the point of a bistoury. A short silver 

 canula, one-half to three-quarters of an inch in diameter, armed at 

 each extremity with a narrow projecting rim or flange, is then in- 

 serted into the wound in the stomach, the edges of which are fast- 

 ened round the tube with a ligature in order, to prevent the escape 

 of the gastric fluids into the peritoneal cavity. The stomach is then 

 returned to its place in the abdomen, and the canula allowed to re- 

 main with its external flange resting upon the edges of the wound 

 in the abdominal integuments, which are to be drawn together by 



1 Experiments and Observations upon the Gastric Juice. Boston, 1834. 



