322 DRS HEPBURN AND WATERSTON ON THE 



its free surface. This globular chamber was marked off from the distal tubular part by 

 a constriction visible externally, and well marked internally. The walls of this chamber 

 were little more than one-sixteenth of an inch (less than 2 mms.) in thickness. The lining 

 mucous membrane was pale, very slightly rugose, and at frequent intervals it presented 

 pin-point depressions surrounded by slightly raised rings of the mucous membrane. This 

 chamber was found empty, but it appeared capable of holding, without distension, 

 material equal in bulk to the size of a small orange. While the inlet opened backwards 

 to the second compartment, the outlet opened forwards into the fourth compartment. 

 The adjacent margins of these two openings were about three-eighths of an inch (9 mms,) 

 apart. The outlet was not so firmly constricted as the inlet, and could transmit the tip 

 of a little finger without being unduly stretched. 



Examined microscopically (PI. II. fig. 5), the mucous membrane was found to rest 

 upon a thick layer of muscularis mucosae, which everywhere sent prolongations into the 

 intertubular intervals. As in the preceding compartment, the surface layer of epithelium 

 had been desquamated, but otherwise the tissue was in a satisfactory condition. It formed 

 a layer averaging about 5 mms. in thickness, and throughout it presented large numbers 

 of tubular glands. At intervals in its deeper half spherical nodules of lymphoid tissue 

 appeared, while all through the intertubular stroma, which was considerable in amount, 

 large numbers of lymph corpuscles were visible. These were most numerous in the 

 immediate vicinity of the lymph nodule. The tubular glands appeared to be fairly 

 simple in their arrangement, and in all probability they do not always branch as 

 they descend into the substance of the mucous membrane. When they do divide, it is 

 probably not oftener than once. Towards their deeper ends they appear to follow a 

 sinuous course, and they may there be somewhat convoluted. The end next the surface 

 tends to be straighter and less wavy. A delicate basement membrane supported the 

 cells which lined the glands. These cells were somewhat cubical in shape, and, while 

 their nuclei were always quite distinct, yet those pertaining to the superficial part of the 

 tubules stained much more deeply than those belonging to the deeper part of the gland. 

 A transverse section of the deep end of a tube examined under a higher power (PI. II. 

 fig. 6) revealed a small circular lumen surrounded by a close-fitting layer of nucleated 

 cells. There was no trace of any arrangement corresponding to parietal cells. The 

 tubules of this and of the succeeding compartment may very fairly be likened to the 

 pyloric glands of other mammals, but instead of being scattered among oxyntic glands 

 and only predominating near, or being exclusively found in the vicinity of the pylorus, 

 they are restricted to the third and fourth compartments, and are not intermingled 

 with oxyntic glands. 



Vessels of different sizes were readily visible in the submucous layer, but the pene- 

 tration of capillaries into the intertubular stroma was not very great, as in the case of 

 the second compartment. It would therefore appear as if the vascularity of this mucous 

 membrane was not a prominent characteristic of its structure. 



The succeeding or fourth compartment was shaped like an inverted V (/\), of which 



