STRUCTURE OF THE STOMACH. 215 



mediate muscular coat, with bloodvessels, lymphatics, and 

 nerves distributed in and between them. 



The muscular coat of the stomach consists of three separate 

 layers or sets of fibres, which, according to their several direc- 

 tions, are named the longitudinal, circular, and oblique. The 

 longitudinal set are the most superficial : they are continuous 

 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 en- 

 circle 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 projecting ring of the pylorus. Accord- 

 ing 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, 

 continuous with the circular muscular fibres of the oesophagus, 

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

 rangement that prevails in the preceding layer: they are com- 

 paratively 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, continu- 

 ous 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 color during 

 life, and in the contracted state is thrown into numerous, chiefly 

 longitudinal, folds or rugae, which disappear 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 shared with 

 the mucous membrane of the small and large intestines, which, 

 doubtless, are connected with the peculiar functions, especially 

 those relating to absorption, which these parts of the alimen- 

 tary canal perform. 



Entering largely into the construction of the mucous mem- 



