SECRETION OF BRUNNER'S GLANDS. 489 



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chloric acid before any conclusions are drawn as to the value of a certain 

 reaction. 



The acid reaction may be partly due to free acid, partly to acid salts (mono- 

 phosphates), and partly^to both. According to LEO,* one can test for acid phos- 

 phates by calcium carbonate, which is not neutralized therewith, while the free 

 acids are. If the gastric content has a neutral reaction after shaking with cal- 

 cium carbonate, and the carbon dioxide is driven out by a current of air, it con- 

 tains only free acid; if it has an acid reaction, acid phosphates are present, 

 and if it is less acid than before, it contains both free acid and acid phosphate. 

 It must not be forgotten that a faint acid reaction may, after treatment with cal- 

 cium carbonate, also be due to the protein. This method can likewise be applied 

 in the estimation of free acid. 



Various titration methods have been suggested for the estimation of the 

 free hydrochloric acid, but these cannot yield conclusive results for the reasons 

 given in Chapter I. For this determination physico-chemical methods (page 74), 

 are necessary, but they have not been used to any great extent for clinical pur- 

 poses. HOLMGREN 2 has suggested a method for estimating hydrochloric acid 

 based upon the adsorption phenomenon. 



A great number of methods have been suggested for the quantitative estima- 

 tion of the total acidity, among which we must mention those of K. MORNER and 

 SJOQVIST, which are extensively used. As the value of a Special determination 

 of the free and total hydrochloric acid is doubtful, or at least disputed, and also as 

 the question is chiefly of clinical interest we must refer to the hand-books of clinical 

 investigations of v. JAKSCH, EULENBURG, KOLLE, and WEINTRAUD and of SAHLI. 

 The same applies to the tests for volatile fatty acids. 



HI. THE GLANDS OF THE MUCOUS MEMBRANE OF THE INTESTINE AND 



THEIR SECRETIONS. 



The Secretion of Brunner's Glands. These glands are partly con- 

 sidered as small pancreatic glands and partly as mucous or salivary 

 glands. Their importance is not the same in all animals. According 

 to GRUTZNER they are in dogs closely related to the pyloric glands and 

 contain pepsin. This also coincides with the observations of GLAESSNER 

 and of PONOMAREW, which differ from each other only in that PONO- 

 MAREW finds that the secretion is inactive in alkaline reaction and con- 

 tains only pepsin, while GLAESSNER claims it is active in both acid and 

 alkaline reaction and that it contains pseudopepsin. According to 

 ABDERHALDEN and RONA the pure duodenal secretion of the dog contains 

 a proteolytic enzyme which does not belong to the trypsin type but 

 rather to the pepsin variety. The statements as to the occurrence of a 

 diastatic enzyme in BRUNNER'S glands are disputed. SCHETJNERT and 

 GRIMMER 3 indeed found diastatic enzyme in the duodenal glands of the 

 horse, ox, pig and rabbit, but no proteolytic or rennin enzyme. 



iCentralbl, f. d. med. Wissensch., 1889, p. 481; Pfliiger's Arch., 48, and Berlin, 

 klin. Wochenschr., 1905, p. 1491. 



2 Deutsch. med. Wochenschr., 1911, p. 247. 



3 Griitzner, Pfliiger's Arch., 12; Glaessner, Hofmeister's Breitrage, 1; Ponomarew, 

 Biochem. Centralbl., 1, 351; Abderhalden and Rona, Zeitschr. f. physiol. Chern., 

 47; Scheunert and Grimmer, cited in Bioch. Centralbl., 5, 673. 



