152 FUNCTIONS OF NUTRITION. 



two kinds of cells is readily visible ; while in those taken during diges- 

 tion, they are hardly to be distinguished from each other.* 



It is doubtful therefore whether we can infer any radical difference .in 

 function for different regions of the stomach from the form of their 

 glandular cells. In the follicles of the middle and cardiac portions the 

 two kinds of cells are associated, while only the smaller kind are found 

 near the pylorus. But Ebsteinf has shown that if two digestive fluids 

 be. prepared by macerating the gastric mucous membrane in acidulated 

 water, using for one the middle portion and for the other the pyloric 

 portion, both fluids possess digestive properties which differ only in 

 degree. According to a still more decisive observation by Heiden- 

 hain,J the pyloric portion, when separated by preliminary operation 

 from the remainder of the stomach, will yield a secretion which com- 

 municates digestive qualities to an acidulated solution. The charac- 

 teristic ingredient of the gastric secretion seems to be produced more 

 or less abundantly in all regions of the stomach, while the differences 

 in function of its different parts, so far as they exist, relate to other 

 particulars not yet fully understood. 



The most important early observations in regard to the gastric juice, 

 were those of Beaumont, in the case of Alexis St. Martin, a patient 

 with permanent gastric fistula, the result of a gunshot wound. The 

 wound caused an opening at the lower part of the left chest, extending 

 through the diaphragm into the fundus of the stomach. After cicatri- 

 zation of the edges of the wound, there remained a fistulous opening, 

 about two centimetres in diameter, leading into the cavity of the 

 stomach. The orifice was usually closed from within by a valvular 

 protrusion of the mucous membrane ; but this could be easily depressed, 

 allowing the interior of the stomach to be inspected, or its contents to 

 be withdrawn for examination. Beaumont's experiments, which were 

 continued at various intervals from the year 1825 to 1832, established 

 the following important facts : First, that the active agent in digestion 

 is an acid fluid, secreted by the walls of the stomach ; secondly, that 

 this fluid is poured out only during digestion, under the influence of 

 food, or of some artificial stimulus ; and finally, that it will exert its 

 solvent action on food outside the body, if kept at the temperature of 

 38 C. He also made investigations as to the effect of various kinds 

 of stimulus on the secretion of the gastric juice, the rapidity with 

 which digestion takes place, and the digestibility of various kinds of 

 food. 



The same person, with his gastric fistula unchanged, after an interval 

 of twenty-four years, came under the observation of Prof. F. G. Smith, 

 of the University of Pennsylvania, who again made a series of similar 

 experiments, confirming and extending those of Beaumont. Another 



* Ewald. Die Lehre von der Verdaunng. Berlin, 1879, p. 39. 

 f Archiv. fur Mikroscopische Anatomic. Bonn, 1870, Band vi., p. 515. 

 J Archiv. fiir die gesammte Physiologic. Bonn, 1878, Band xviii., p. 169. 

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



