6 ME. JAMES JOHNSTONE ON THE 



stomach, and, like these, contain the typical central and parietal 

 cells. In sections taken parellel to the surface of the gland, 

 these tubules are for the most part cut longitudinally, though 

 many are obliquely and even transversely cut. 



In a nearly sagittal section (PI. 1. fig. 1), taking in pyloric 

 and oesophageal orifices, the extent of the gland exhibited 

 is rather less than io one passing to one side o£ the oesophagus. 

 This is due to the extension of the gastric gland laterally 

 to the oesophageal opening. x\ll the layers of the stomach- 

 wall are present. The serosa (ser.) is scanty in the middle line, 

 but can be recognized ; the muscularis (musc.l., tnusc.t.) is rather 

 reduced ; the submucosa (s?n.) is largely encroached on by the 

 folded mucosa and the presence of muscle bundles between these 

 folds. The mucosa itself (muc), to which the great thickness of 

 the wall is due, is seen to have undergone an elaborate folding. 

 At the pyloric extremity there is a gradual transition between 

 tubules containing the pai'ietal cells, which are present in the 

 gland, and the epithelium immediately adjoining on the pylorus 

 {muc.py.), in which the primary gland-tubules contain only 

 central cells. At the oesophagus there is a sharp transition 

 between those parietal-celled tubules which are present on the 

 epithelium to the left of the former and the stratified oesophageal 

 lining. 



In any one section in such a plane (PI. 1. fig. 1) one or more 

 of the openings (o) of the gland are cut through. These are 

 then seen to lead into a more or less complex system of cavities, 

 into which the mucosa is prolonged. There appear, also, isolated 

 portions of the mucosa often containing a lumen, and in which 

 the pjimary gland tubules are cut in all possible planes. 

 Accompanying each of the secondary tubules making up the 

 gastric gland is a sheet of muscularis mucosae (PI. 1. fig. 3, mm.). 

 As stated above, this consists of a tunic containing fibres mostly 

 running transversely to the long axis of the tubule. 



The muscularis is present over the whole surface of the 

 gland. Passing from the pyloric to the cardiac extremity, the 

 strongly developed layer of transversely running fibres forming 

 the pyloric sphincter {m.py.) thins out with the commence- 

 ment of the gland-thickening, and is almost entirely replaced 

 by a layer of striated muscle fibres (PI. 1. fig. 1, munc.t.). The 

 course of these is both transverse and longitudinal to the long 

 axis of the stomach ; and the arrangement is such that the 



