GASTRIC JUICE. 235 



into the stomach of a dog by a fistula, produced a flow of juice much less abundant than 

 when the same quantity was taken by the mouth. To convince himself that this did not 

 depend upon the want of admixture with the alkaline saliva, he mixed the sugar with saliva 

 and passed it in by the fistula, when the same difference was observed. It is a curious 

 fact that, in some animals, particularly when they are very hungry, the sight and odor 

 of food will induce secretion of gastric juice. 



The gastric juice is probably one of. the most sensitive of the secreted fluids to dis- 

 turbing influences. It was remarked by Beaumont that a febrile condition of the system, 

 the depression resulting from an excess in eating and drinking, or even purely mental 

 conditions, such as anger or fear, vitiated, diminished, and sometimes entirely suppressed 

 secretion by the stomach. At some times the mucous membrane became red and 

 dry, and at others it was pale and moist. In such morbid conditions, it is stated that 

 drinks were immediately absorbed, but that food remained in the stomach undigested for 

 twenty-four or forty-eight hours. 



The influence of the nervous system on the secretion of gastric juice, exerted particu- 

 larly through the pneumogastric nerves, is very marked and important, but its considera- 

 tion belongs properly to the section on the nervous system. 



After the food has been in part liquefied and absorbed and in part reduced to a pulta- 

 ceous consistence, the secretion of gastric juice ceases; the movements of the stomach 

 having gradually forced that portion of the food which is but partially acted upon in this 

 organ or is digested only in the small intestines, out at the pylorus. The stomach is thus 

 entirely emptied, the mucous membrane becomes pale, its reaction loses its marked acid 

 character and becomes neutral or faintly alkaline. 



Secretion in Different Parts of the Stomach. The differences already noted in the 

 anatomy of the mucous membrane of the stomach in different parts of the organ point 

 to the important question of a possible difference in the physiological action of the secre- 

 tions of different parts, particularly the pyloric portion and the rest of the general surface. 

 We can learn but little that is definite with regard to this point from observations on 

 the inferior animals, unless they be confirmed in the human subject. The observations, 

 however, of Kolliker, Goll, and Donders, on the pig, are very satisfactory, and subse- 

 quently they were fully confirmed as regards the human subject. It is well known that an 

 acidulated infusion of the mucous membrane of the stomach possesses, if properly pre- 

 pared, all the digestive properties of the true gastric juice, and that this is not the case 

 with similar infusions of the mucous membrane from any other parts. Kolliker, in ex- 

 periments on artificial digestion made in conjunction with Dr. Goll, " on the gastric mu- 

 cous membrane of the pig, clearly showed that the two kinds of glands entirely differ in 

 respect of their solvent power ; inasmuch as those with the round cells dissolved acidu- 

 lated coagulated protein-compounds in a very short time ; those with cylindrical epithe- 

 lium, on the contrary, either did not operate at all, or produced a slight effect only after 

 a longer period." The same author farther states that these observations were confirmed 

 by Donders and himself in the human stomach. 



Although the character of the secretion in different parts of the stomach is not the 

 same in all animals, it must be admitted that, in man, the mucous membrane of the stom- 

 ach, in what is called the pyloric zone, does not secrete the true, acid, solvent, gas- 

 tric juice. In other words, this fluid is produced only in those portions of the stomach 

 in which the mucous membrane is provided with tubes lined with cells of glandular epi- 

 thelium, or what have been called the stomach-cells. 



In most of the modern works on physiology, allusion is made to the probable quantity 

 of gastric juice secreted in the twenty-four hours. The estimates on this point can be 

 only approximative, even in the inferior animals, and they give no definite information 

 concerning the normal quantity in the human subject. Bidder and Schmidt, Lehmann, 

 Corvisart, and others, have made calculations of the probable quantity, either by collect- 

 ing the juice for a certain time and multiplying the quantity thus obtained by a number 



