126 THE DIGESTIVE FLUIDS. 



THE GASTRIC JUICE. 



General Considerations. The gastric juice is the secretory 

 product of the glandular structures of the stomach, and the only 

 digestive fluid which presents an acid reaction. In pure form it is 

 best obtained from animals according to one of the methods devised by 

 Pawlow and his pupils, viz., by the formation of a blind stomach 

 pouch, with a fistulous opening to the outside ; or by the establishment 

 of a double oesophageal and a single gastric fistula, arranged in such 

 manner that the food eaten by the animal is discharged from the 

 oesophagus instead of entering the stomach. On feeding the animal 

 pure gastric juice is then obtained, uncontaminated by any food ma- 

 terial. Procured in this manner it appears as a clear or but slightly 

 opalescent yellowish fluid, which has a very characteristic odor and 

 a strongly acid reaction. Its density varies between 1.002 and 1.003. 



On microscopic examination epithelial cells from the lining of the 

 glandular ducts, goblet-cells, mucous corpuscles, free nuclei, and a 

 variable number of bacteria are found. In addition, we often observe 

 small tapioca-like bodies, which under the microscope are seen to 

 contain numerous formations resembling snail-shells, and which 

 probably consist of altered mucin. 



Amount. Of the total amount of gastric juice secreted in the 

 twenty-four hours, but little is known. Its secretion is influenced 

 by numerous factors, such as the appetite, the act of mastication, 

 the quality and quantity of the food ingested, the age and sex of 

 the individual, the time of day (notably in relation to the taking of 

 food), the psychic state of the individual, etc. 1 According to Bidder 

 and Schmidt, the amount corresponds to about one- tenth of the 

 body-weight, so that a man weighing 70 kilogrammes would secrete 

 about 7000 grammes in the twenty-four hours. This figure, how- 

 ever, I regard as too high, and am inclined to place the amount at 

 from 2000 to 3000 c.c. 



Some of the results which have been obtained by Pawlow are 

 shown in the following table ; the figures have reference to the 

 ingestion of 200 gms. of meat, 200 gms. of bread, and 600 gms. 

 of milk respectively : 



Amount in c.c. Digestive power in mm. 2 



Hours. Meat. Bread. Milk. Meat. Bread. Milk". 



1 11.2 10.6 4.0 4.94 6.10 4.21 



2 11.3 5.4 8.6 3.03 7.97 2.35 



3 7.6 4.0 9.2 3.01 7.15 2.35 



4 5.1 3.4 7.7 2.87 6.19 2.65 



5 2.8 3.3 4.0 3.20 5.29 4.63 



6 2.2 2.2 0.5 3.58 5.72 6.12 



7 ...... 1.2 2.6 . . 3.25 5.48 



8 0.6 2.2 . . 3.87 5.50 



9 0.9 . . . . 5.75 



10 0.4 



1 The secretion of the gastric juice, like that of the pancreatic juice, has been shown to 

 be referable to a specific hormone. 



2 Measured by the number of mm. of digested egg-albumin in Mett tubes (see Estimation of 

 pepsin). 



