266 DIGESTION. 



tinuous with the longitudinal fibres of the oesophagus, and 

 spread out in a diverging manner over the great end and 

 sides of the stomach. They extend as far as the pylorus, 

 being especially distinct at the lesser or upper curvature of 

 the stomach, along which they pass in several strong bands. 

 The next set are the circular or transverse fibres, which more 

 or less completely encircle all parts of the stomach ; they 

 are most abundant at the middle and in the pyloric portion 

 of the organ, and form the chief part of the thick project- 

 ing ring of the pylorus. According to Pettigrew, these 

 fibres are not simple circles, but form double or figure- 

 of 8 loops, the fibres intersecting very obliquely. The next, 

 and consequently deepest set of fibres, are the oblique, con- 

 tinuous with the circular muscular fibres of the oesophagus, 

 and, according to Pettigrew, with the same double -looped 

 arrangement that prevails in the preceding layer: they 

 are comparatively few in number, and are placed only at 

 the cardiac orifice and portion of the stomach, over both 

 surfaces of which they are spread, some passing obliquely 

 from left to right, others from right to left, around the 

 cardiac orifice, to which, by their interlacing, they form a 

 kind of sphincter, continuous with that around the lower 

 end of the oesophagus. The fibres of which the several 

 muscular layers of the stomach, and of the intestinal canal 

 generally, are composed, belong to the class of organic 

 muscle, being composed of smooth or unstriped, elongated, 

 spindle-shaped fibre-cells ; a fuller description of which 

 will be given under the head of Muscular Tissue. 



The mucous membrane of the stomach, which rests upon 

 a layer of loose cellular membrane, or submucous tissue, 

 is smooth, level, soft, and velvety ; of a pale pink colour 

 during life, and in the contracted state is thrown into 

 numerous, chiefly longitudinal, folds or rugae, which dis- 

 appear when the organ is distended. 



In its general structure the mucous membrane of the 

 stomach resembles that of other parts (see Structure of 

 Mucous Membrane). But there are certain peculiarities 



