1/4 MESSRS. SCHAFER AND WILLIAMS ON THE [Jail. 18, 



Two such clefts of considerable size are seen between tbe glands in 

 fig. 5 ; other smaller clefts, also for the most part representing sec- 

 tions of lymphatics, are seen in the interglandular tissue in various 

 parts of the mucous membrane. It will be observed, moreover, that 

 the lymphoid tissue at the base of the glands is more abundant here 

 than in the rest of the second region (fig. 2), with the exception of 

 the lymphoid patches, and that the prolongations of the muscularis 

 mucosae towards the surface between the glands are more numerous 

 (m'.?n). 



The Mucous Membrane of the Third Region. — This is very thick 

 both in Dorcopsis luctuosa and in Macropus giganteus, the thickness 

 being as usual due to the length of the gland-tubes. These resem- 

 ble in many respects the pyloric part of the second region just 

 described ; thus they are long straight tubes lined near the orifice 

 with columnar epithelium, and in all the rest of their extent with 

 small cubical or polyhedral cells, which in many parts nearly fill up 

 the tubes. But there is this important difference, that superadded 

 to these and situated outside of them (but still within the basement 

 membrane, which they often cause to bulge outwards) there are, in 

 the middle parts of the length of the gland (figs. 6 & 7), certain 

 other cells of a spheroidal or ovoidal shape and granular appearance. 

 These are what have long been known as peptic cells ; since it is 

 believed, although it has not yet been conclusively proved, that they 

 are the source of the pepsin of the gastric juice. They were termed 

 by Rollett* the delomorphous cells of the gland, whilst the other, 

 more centrally situated, and usually less obvious cells, which are 

 continuous above with the columnar epithelium of the surface, he 

 has termed adelomorphous. For the present it will be better to 

 adhere to the old terminology (peptic cells) for the rounded cells, 

 and to term the angular ones, which line the whole tube within them, 

 central cells. The glands, moreover, in which the peptic cells occur 

 we may continue to term the peptic glands, and the region of the 

 stomach occupied by them the peptic region, without at the same 

 committing ourselves so far as to maintain that the other portions 

 of the stomach do not also, as some physiologists think, yield 

 pepsin. 



To return to the structure of the glands. The spheroidal peptic 

 cells vary in number in different glands, being fewest in the parts of 

 the peptic region which are nearest the boundary between this and 

 the second or general glandular region. It frequently happens that 

 these peptic cells do not reach the fundus (6) of the gland, which 

 is not larger in these glands than the rest of the tube, and is occu- 

 pied exclusively by central cells which resemble the cubical cells 

 of the other glands, but are smaller and more closely packed. The 

 distribution of the peptic cells in the glands is well shown in fig. 6, 

 which is a sketch of part of a vertical section from the middle of the 

 peptic region as seen under a low power. The preparation was 

 stained with aniline blue, according to Ileidenhain's directions-)-; the 

 peptic cells become much more deeply stained by this than the rest 



* Uutersuchungen, 1871. t Arch. f. mikr. Anat. vi. 1870. 



