COMPOSITION OF THE GASTRIC JUICE. 237 



vegetable, confervoid growth, upon the surface, some of which breaks up and falls to the 

 bottom of the vessel, forming a whitish, tlocculent sediment. We have now (1875) a 

 specimen of gastric juice which was taken from a dog witli a gastric fistula in January, 

 1862. It has no putrefactive odor and is apparently in the same condition as when it 

 was first drawn. In addition to this remarkable faculty of resisting putrefaction, this 

 process is arrested in decomposing animal substances, both when taken into the stomach 

 and when exposed to the action of the gastric juice out of the body. 



There are on record no minute quantitative analyses of the human gastric juice, 

 except those by Schmidt, of the fluid from the stomach of a woman with gastric fistula; 

 and in this case there is reason to suppose that the secretion was not normal. The analysis 

 of the gastric juice of St. Martin by Berzelius was not minute. The analyses of Schmidt 

 give less than six parts per thousand of solid matter, while Berzelius found over 

 twelve parts per thousand. In all the comparatively recent analyses, there have been 

 found a free acid or acids ; a peculiar organic matter, generally called pepsin ; and various 

 inorganic salts, among which may be mentioned as most important, the chlorides of 

 sodium, potassium, and calcium, with the phosphates of lime, magnesia, and iron. Of 

 these constituents, the salts possess little physiological importance as compared with the 

 organic matter and the acid principles. 



The following analysis by Bidder and Schmidt gives the mean of nine observations 

 upon dogs: 



Table of Solid Constituents of the Gastric Juice of the Dog. 

 (Bidder and Schmidt.) 



Ferment (pepsin.) , 17*127 



Free hydrochloric acid (?) 3'050 



Chloride of potassium 1*125 



Chloride of sodium 2*507 



Chloride of calcium 0'624 



Chloride of ammonium 0'468 



Phosphate of lime 1*729 



Phosphate of magnesia 0*226 



Phosphate of iron 0*082 



26-938 



In another series of three experiments, in which the saliva was allowed to pass into 

 the stomach, the proportion of free acid was 2*337, and the proportion of organic matter 

 was somewhat increased. 



Organic Principle of the Gastric Juice. This principle, called pepsin or gasterase, is 

 an organic nitrogenized body, peculiar to the gastric juice, and, as we shall see farther on, 

 is essential to its digestive properties. When the gastric fluid was first obtained, even by 

 the imperfect methods employed anterior to the observations of Beaumont and of Blond- 

 lot, an organic matter was spoken of as one of its constituents. 



Experiments on artificial digestive fluids, by Eberle, Schwann and Miiller, Wasmann, 

 and others, have demonstrated that acidulated infusions of the mucous membrane of the 

 stomach, possessing all the physiological properties of the gastric juice, contain an organic 

 matter, first isolated by Wasmann, on which the solvent powers of these acid fluids seem 

 to depend. Mialhe, who has obtained this substance in great purity by the process recom- 

 mended by Vogel, describes the following properties as characteristic of the organic 

 matter in artificial gastric juice : Dried in thin slices on a plate of glass, it is in the form 

 of small, grayish, translucent scales, with a faint and peculiar odor and a feebly bitter 

 and nauseous taste. It is soluble in water and in a weak alcoholic mixture, but is in- 

 soluble in absolute alcohol. A solution of it is rendered somewhat turbid by a tempera- 



