PHYSIOLOGICAL CONSIDERATIONS 19 



discussed by E. Weinland and by M. van Herwerden) 52 but 

 for that matter the entire question is of lessened importance, 

 since we have come to recognize the positive influence of com- 

 bined hydrochloric acid in peptic digestion (v. sup.). Be- 

 sides, the pepsin of fishes apparently is not entirely identical 

 with that of the mammalia. 



Gastric digestion in amphibia, reptiles and birds 53 cor- 

 responds doubtless with the peptic type. In graminivorous 

 birds, whose food is first acted upon in a crop, the peptic 

 catabolism of protein may begin even in this organ. 



From the point of systematic investigation of the com- 

 parative physiology of digestion in mammals 54 Ellenberger 

 and Scheunert, scientists in the Veterinary High School in 

 Dresden, have rendered most important service. In the 

 ruminants, with three complex pro ventricles preceding the 

 glandular stomach, it goes without saying that complicated 

 processes of digestion are met. The hamster with its two- 

 chambered stomach presents interesting features, the first 

 lined with a cutaneous type of mucous membrane and con- 

 nected by a very narrow opening with the glandular stomach 

 proper, thus occupying an intermediate position between the 

 many-chambered stomach of the ruminants and the single- 

 chambered stomach of the solipeds, the hog and other 

 mammals. The digestion of the food proteins by the gastric 

 juice takes place only in the gland-bearing stomach, while 



53 M. van Herwerden (Physiol. Institut., Utrecht), Zeitschr. f. physiol. 

 Chem., 56, 453, 1908; E. Weinland, Zeitschr. f. Biol., 55, 58, 1911. 



63 Literature upon gastric digestion in Amphibia, Reptiles and Birds : A. 

 Scheunert, Handb. d. Biochem., 3", 168-170, 1909; W. Biedermann, 1. c., pp. 

 1272-1281. 



"Literature upon the comparative physiology of gastric digestion in 

 Mammalia: A. Scheunert, Handb. d. Biochem., 3", 153-162, 1909; W. Bieder- 

 mann, 1. c., pp. 1299-1311; W. Ellenberger and A. Scheunert, Lehrb. d. vergl. 

 Physiol., Berlin, P. Parey, 1910; A. Scheunert, Vergleichende Studien iiber den 

 Eiweiszabbau im Magen, O. Wallach, Festchrift, Gottingen, 1909; and Pfliiger's 

 Arch., 109, 145, 1905, and 189, 131, 1911; A. Scheunert and E. Rosenfeld, 

 Deutsche tierarztl. Wochenschr., 17, No. 25; A. Scheunert and W. Grimmer, 

 Zeitschr. f. physiol. Chem., 58, 27, 1906; E. Rosenfeld, Inaug. Diss., Leipzig, 

 1908; A. Schattke, Inaug. Diss., Dresden, 1909; F. Bengen and G. Haane, 

 Pfliiger's Arch., 106, 267, 286, 1905. 



