GASTRIC DIGESTION. 345 



Gastric juice may also be obtained from man either by withdrawing the con- 

 tents of the stomach by means of the stomach-pump, or it may be obtained, as 

 it has been done in several instances, through a fistulous opening made into'the 

 stomach, either accidentally, as in the case of St. Martin, or, as in the case studied 

 by Richet, in which the operation of gastrotomy was performed by Verneuil for 

 impermeable stricture of the oesophagus. 



Gastric juice collected from a gastric fistula is a thin, limpid, almost 

 colorless liquid of strongly acid reaction and of a specific gravity of 

 about 1010. ' It has a peculiar odor which is generally characteristic of 

 the animal from which it is obtained. The filtered gastric juice of the 

 dog contains from 1.05 to 1.48 per cent, solids; of the horse, 1.12 per 

 cent., and of man, 1.21 per cent. It rotates the plane of polarized light 

 to the left, and it is not rendered turbid by boiling, and resists putrefac- 

 tion for a long time. The quantity of gastric juice secreted in twenty- 

 four hours is only with difficulty determined, and the great discrepancy 

 which exists between the various estimates which have been placed on 

 this amount shows that it must vary very widely under different con- 

 ditions. Thus, Beaumont estimated that one hundred and eighty 

 grammes of gastric juice were secreted daily ; Griinewald, from studies 

 made on a similar case of gastric fistula, concluded that 26.4 per cent, 

 of the body weight represented the amount of gastric juice daily poured 

 out ; while Bidder and Schmidt, from operations made on clogs, esti- 

 mated that the daily secretion of gastric juice corresponded to about 

 one-tenth of the body weight. 



The gastric juice of a dog, even after having fasted for a long time, 

 can never be collected perfectly pure from a gastric fistula, since it 

 always is contaminated and mixed with remnants of undigested food, 

 sancl, and hairs from the edges of the wound, etc. In the sheep it is 

 even more difficult to obtain perfectly pure gastric juice, since Bidder 

 and Schmidt have found that even after thirty-six hours particles of food 

 were still contained in the fourth stomach. When filtered, gastric juice 

 is always clear and limpid, almost colorless, or j-ellowish in the dog, 

 brownish in the sheep. Gastric juice resists putrefactive changes to a 

 remarkable degree, and may be kept for an almost indefinite period 

 without undergoing change. 



Acids and heating produce no precipitation in gastric juice, as is 

 also the case with lime, chloride of iron, sulphate of copper, and ferro- 

 cyanide of potassium ; alkalies, on the other hand, produce precipitation, 

 which consists of calcium phosphate with iron and magnesium phosphate 

 and some organic matter. Corrosive sublimate always produces a pre- 

 cipitate, which consists mainly of the digestive ferments. Alcohol and 

 acetate of lead give an abundant precipitate, which consists mainly of 

 the ferment. 



The gastric juice is poor in solids, containing not more than two per 



