. GASTRIC DIGESTION 143 



gastric juice of low acidity is secreted either from physiological or patho- 

 logical cause. The digestion of fat in the stomach is, however, at 

 most, of but slight importance as compared with the digestion of fat in 

 the intestine through the action of the lipase of the pancreatic juice 

 (seepage 192). 



Boldyreff 1 has shown trypsin to be present in stomach contents, due 

 to regurgitation of intestinal contents through the pylorus. This claim 

 has been verified by others 2 (see Chapter VIII on Gastric Analysis). 



The gastric response 3 to different foods varies widely. There is 

 also a great variation in normal stomachs. Some such stomachs empty 

 slowly, others rapidly some give high acidities, others low acidities. 



COLLECTION OF HUMAN GASTRIC JUICE 



, Have one or more volunteers from the class take^ the Rehfuss Stomach Tube 

 as directed on page 162. The subjects must omit breakfast if the tube is taken 

 in the morning or luncheon if taken in the afternoon. Empty the stomach 

 (see pp. 163-4) and, with the tube still in place, allow each subject to drink 

 250 c.c. of water. The water will stimulate the flow of gastric juice and will 

 itself quickly leave the stomach. In many instances fairly concentrated gastric 

 juice may be obtained from the stomach in from 30 to 45 minutes after the 

 introduction of the water. Remove this gastric juice according to procedure 

 outlined on pp. 164-5. For composition of human gastric juice see page 155. 

 See also Experiment n, page 149. If thought desirable the gastric juice result- 

 ing from psychical stimulation (see page 149) may be collected instead of that 

 following the chemical stimulation of water. (Curves showing the stimulatory 

 power of water are given in Figs. 41 and 42.) 



PREPARATION OF AN ARTIFICIAL GASTRIC JUICE 



Dissect the mucous membrane of a pig's stomach from the muscular por- 

 tion and discard the latter. Divide the mucous membrane into two parts (4/5 

 and 1/5). Cut up the larger portion place it in a large-sized beaker with 0.4 



Boldyreff: Quart. Jour. Exper. PhysioL, 8, i, 1914. 



2 Spencer Meyer, Rehfuss and Hawk: Am. Jour. PhysioL, 39, 459, 1916. 



3 1. Intragastric Conductance Bergeim: Am. J. PhysioL, 45, i, 1917. 



II. Milk Bergeim, Evvard, Rehfuss, Hawk: Am. J. Physiol., 48, 411, 1919- 



III. Beef Fishback, Smith, Bergeim, Lichtenthaeler, Rehfuss, Hawk; Am. J. PhysioL, 

 49, 174, 1919. 



IV. Pork Smith, Fishback, Bergeim, Rehfuss, Hawk: Am. J. PhysioL, 49, 204, 1919. 

 V. Lamb Fishback, Smith, Bergeim, Rehfuss, Hawk: Am. J. PhysioL, 49, 222, 1919. 



VI. Eggs Miller, Fowler, Bergeim, Rehfuss, Hawk: Am. J. PhysioL, 49, 254, 1919. 

 VII. Vegetables Miller, Fowler, Bergeim, Rehfuss, Hawk: Am. J. PhysioL, 51, 332, 

 1920. 



VIII. Unpalatable Food Holder, Smith, Hawk: Set., 51, 299, 1920. 

 IX. Influence of Worry Miller, Bergeim, Hawk: Sci., 52, 253, 1920. 

 X. Psychic Secretion Miller, Bergeim, Rehfuss, Hawk: Am. J. PhysioL, 52, i, 1920. 

 XI. Tea, Coffee, Cocoa Miller, Bergeim, Rehfuss, Hawk: Am. J. PhysioL, 52, 28, 

 1920. 



XII. Pies, Cakes, Puddings Miller, Fowler, Bergeim, Rehfuss, Hawk: Am. J. PhysioL, 

 52, 248, 1920. 



XIII. Sugars and Candies Miller, Bergeim, Rehfuss, Hawk: Am. J. PhysioL, 53, 65, 

 1920. 



