CHANGES OF FOOD IN THE ALIMENTARY CANAL. 



153 



formed in the larger granular and more spheroidal gland-cells. 1 Klein, 

 however, has shown that the two extreme forms of glands are connected by 

 so many intermediate forms, that it is impossible to draw a very definite line 

 between those secreting mucus exclusively, and those which produce both 

 pepsin and mucus.' 2 According to M. Cl. Bernard, 3 when the stomach is 



FIG. 67. 



FIG. 68. 



FIG. 67. Peptic gastric gland ; a, common trunk ; 6, b, its chief branches ; c, c, terminal caeca with 

 spheroidal gland-cells. 



FIG. 68. Portions of one of the cseca more highly magnified, as seen longitudinally (A), and in trans- 

 verse section (B) ; a, basement-membrane ; b, large glandular cell ; c, small epithelium cells surround- 

 ing the cavity. 



empty, the columnar epithelium which lines the neck of the glands com- 

 pletely blocks up their orifices, so that during fasting these appear as slightly 

 prominent papillae ; but when the secretion of gastric fluid commences, this 

 epithelium is cast forth by the pressure from beneath. The matrix of the 

 mucous membrane of the stomach in which the glands are imbedded, con- 

 sists of adenoid tissue, or a fibrous network containing cells and nuclei. This 

 is more dense in some parts than in others, which has led various observers 

 to admit the existence of lenticular or solitary glands in the region ; but these 



1 SeeKolliker, Microscop. Anat. , 18GO, p. 321 : and Heidenhain, Schultze's Archiv, 

 Bd. vi. Ebstein and Griitzner, however (Pfliiger's Archiv, 1872, Bd. vi, p 1), 

 think that the columnar cells form the pepsin. See also Rollet, Untersuch. aus. der 

 Phys. Inst. in Graz, Band ii. 



2 The hest accounts of the structure of the mucous membrane of the stomach, and 

 of the gastric glands, are given by Messrs. Todd and Bowman, Physiological Anat- 

 omy, vol. ii, pp. 190 et seq. ; by Prof. Kolliker, Mikros. Anat., Bd.'ii, \ 103 ; by Dr. 

 Brinton, in the Supp. to the Cyc. Anat. and Phys. ; and in Med.-Chir. Kev., July, 

 1862, p. 189; by Henle, Eingeweidelehre, p. 152; and by Dr. Klein, Strieker's Histol- 

 ogv, 1870, p. 543. 



' 3 Guz. Med., Mars, 1844. 



11 



