796 Proceedings of Royal Society of Edinburgh. [sess. 
wall of the oesophagus, viz., a thin outer longitudinal and a thick 
inner circular layer, separated by loose areolar tissue, containing 
blood-vessels and a small amount of yellow elastic tissue ; this is an 
arrangement which obtains throughout the entire stomach. In 
this compartment the longitudinal fibres converge towards the 
apical end of the appendage.* 
3. The submucous coat is in the form of a layer of loose areolar 
tissue of considerable thickness, in the outer part of which small 
masses of fat are found, and throughout which a few yellow elastic 
fibres are dispersed. Numerous blood-vessels are present, and im- 
mediately under the mucous membrane the areolar tissue becomes 
denser, and contains numerous muscle fibres running, for the most 
part, longitudinally. The elements of this coat are similarly arranged 
in the walls of all the compartments. 
4. The mucous membrane is similar in structure to that of the 
oesophagus, and consists of a dense layer of laminated horny 
epithelium. 
A section through one of the nipple-like processes of this com- 
partment shows a core of connective tissue surrounded by epithelium 
(Plate I. fig. 1, and Plate II. fig. 1). In the centre of the core 
the connective tissue is loose and open, but nearer the epithelium 
it becomes much more dense. In the core numerous bundles of 
muscular tissue are seen, arranged circularly and longitudinally in 
the peripheral portion, circularly nearer the centre. The blood-vessels 
are extremely well developed, the larger trunks running in the centre, 
the smaller at the periphery. The arteries, which are numerous, have 
the ordinary structure, with this exception, that their walls are very 
stout, especially the tunica adventitia; the veins have in like 
manner a well-developed adventitious coat. A complex system of 
lymphatics is present, especially under the epithelium, where they 
assume the form and arrangement of large sinuses. 
From the observations we have made, we feel convinced that the 
so-called first compartment is in no way to be looked upon as part 
of the stomach proper. It is rather a somewhat globular dilatation 
* It is just possible that this may have to be looked upon as the direct con- 
tinuation of the oesophagus, as we find that the longitudinal muscles converge 
in a most peculiar manner at the apex wherethe wall is exceedingly thin, and 
there is formed a small stellate mass of fibrous tissue at this point, into which 
the particular fibres are inserted as it were. 
