COMPOSITION OF THE GASTRIC JUICE. 465 



secretion of juice. On the other hand FROUIN 1 observed that the intro- 

 duction of saliva into the large stomach of dogs, acts favorably upon 

 the secretion in the small stomach (see page 462), and the acidity as well 

 as the digestive activity of the juice is increased. This action does not 

 depend, according to FROUIN, upon the alkali of the saliva. 



The Qualitative and Quantitative Composition of the Gastric Juice. 

 The human gastric juice, which can seldom be obtained pure and free 

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

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

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

 or their nuclei, and more or less changed columnar epithelium. 



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

 acid, whi|ch, 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 2 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 acid of the stomach is lactic 

 acid, according to GMELIN. S The quantity of free hydrochloric acid in 

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

 p. m., and in cats an average of 5.20 p. m. HC1. 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 4 ) that the amount 

 of hydrochloric 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 phys- 

 ical methods are almost identical with those obtained by titration (P. 



FRANCKEL 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 Compt. rend. soc. biol., 62. 



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

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



3 Pfliiger's Arch., 90 and 103. 



4 See Richet, 1. c.; Contejean, 1. c.; Verhaegen, "La Cellule," 1896 and 1897; 

 Sommerfeld, Bioch, Zeitschr, 9, and also footnote 1, page 464, and the literature on 

 the estimation of hydrochloric acid in the gastric juice contents (p. 489) ; see also 

 Cohnheim and Dreyfus, Zeitschr. f. physiol. Chem. 58 (1908). 



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



6 i.e. 



