GASTRIC JUICE. 441 



from residues of the food or from mucus and saliva, is a clear, or only 

 very faintly cloudy, and nearly colorless fluid of an insipid, acid taste 

 and strong acid reaction. It contains, as form-elements, glandular cells 

 or their nuclei, mucus-corpuscles, and more or less changed columnar 

 epithelium. 



The acid reaction of the gastric juice depends on the presence of free 

 acid, which, as has been learned from the investigations of C. SCHMIDT, 

 RICHET, and others, consists, when the gastric juice is pure and free 

 from particles of food, chiefly or in large part of hydrochloric acid. CON- 

 TEJEAN 1 regularly found traces of lactic acid in the pure gastric juice 

 of fasting dogs. After partaking of food, especially after a meal rich in 

 carbohydrates, lactic acid occurs abundantly, and sometimes acetic 

 and butyric acids. In new-born dogs the acicl of the stomach is lactic 

 acid, according to GMELix. 2 The quantity of free hydrochloric acid in_ 

 the gastric juice is,. according to PAWLOW and his pupils, in dogs 5-6 p. m. r 

 and in cats an average of 5.20 p. m.'HCl. In man the results obtained 

 are variable but regularly much lower. Since it has been possible 

 to obtain pure human gastric juice for investigation it has been found 

 (UMBER, HORNBORG, BICKEL, SOMMERFELD 3 ) that the amount of hydro- 

 chloric acid is about 4-5 p. m. There is hardly any doubt that at least 

 a part of the hydrochloric acid of the gastric juice does not exist free in the 

 ordinary sense, but combined with organic substances. The results 

 obtained in testing for the acidity of gastric juice by physical methods 

 are nearly identical with those obtained by titration (P. FRANCKEL 4 ). 



As chief organic constituent, perfectly fresh gastric juice (of dogs) 

 contains a very complex substance (or perhaps a mixture of substances) 

 which coagulates on boiling and which separates on strongly cooling 

 the juice. This substance is considered, by certain experimenters (NENCKI 

 and SIEBER, and PAWLOW) as the conveyor of the several ferment actions 

 of the gastric juice, i.e., the pepsin as well as the rennin action. It con- 

 tains lecithin and chlorine, and yields nucleoprotein, proteose, purine 

 bases, and pentose as cleavage products (NENCKI and SIEBER 5 ). 



The specific gravity of gastric juice is low, 1.001-1.010. It is corre- 

 spondingly poor in solids. Earlier analyses of gastric juice from man, 

 the dog, and the sheep were made by C. SCHMIDT. 6 As these analyses 



1 Bidder and Schmidt, Die Verdauungssafte, etc., 44; Richet, 1. c.; Contejean, Con- 

 tributions a I'Stude de la physiol. de 1'estomac, Theses, Paris, 1892. 



2 Pfliiger's Arch., 90 and 103. 



3 See Richet, 1. c.; Contejean, 1. c.; Verhaegen, "La Cellule," 1896 and 1897; Som- 

 merfeld, Bioch. Zeitschr. 9, and also footnote 1, page 440, and the literature on the 

 estimation of hydrochloric acid in the gastric juice contents (p. 465). 



4 Zeitschr. f. exp. Path. u. Therap., 1. 



5 Zeitschr. f. physiol. Chem., 32. 

 "I.e. 



