228 



DIGESTION. 



The blood-vessels of the muscular coat are quite numerous and are arranged in a 

 peculiar, rectangular net-work, which they always present in the non- striated muscular 

 tissue. The nerves belong chiefly to the sympathetic system and are demonstrated with 

 difficulty. 



FIG. 55. Fibres seen with the stomach everted. (Sappey.) 



1, 1, oesophagus ; 2, circular fibres at the cesophageal opening ; 8. 3. circular fibres at the lesser curvature ; 4, 4, circu- 

 lar fibres at the pylorus ; 5, 5. 6, 7, 8, oblique fibres ; i, 10, fibres of this layer covering the greater pouch ; 11, por- 

 tion of the stomach from which these fibres have been removed to show the subjacent circular fibres. 



Mucous Coat. Passing from the oesophagus to the stomach, a very marked change 

 takes place in the character of the mucous membrane. The white, hard appearance of 

 the oesophageal lining, due to its covering of pavement-epithelium, abruptly ceases, pre- 

 senting a sharply-defined, dentated border; and the membrane of the stomach is soft, 



velvety in appearance, and of a reddish-gray 

 color. In some of the inferior animals, as the 

 horse, the characteristic membrane of the oesoph- 

 agus is prolonged into the stomach and forms 

 a large, white zone around the cardiac opening, 

 with abruptly-defined edges, contrasting strong- 

 ly with the rest of the lining membrane of the 

 stomach. 



The mucous lining of the stomach is loosely 

 attached to the submucous muscular tissue and 

 is thrown into large, longitudinal folds, which 

 become effaced as the organ is distended. When 

 the muscular coat of the stomach is in a condi- 

 tion of cadaveric rigidity, the longitudinal fold- 

 ing of the mucous membrane is very marked. 

 If the mucous membrane be stretched or if the 

 stomach be everted and distended, and the 

 mucus, which always exists in greater or less 

 abundance over the surface, be gently removed 

 under a stream of water, the membrane will be found marked with innumerable po- 

 lygonal pits or depressions, enclosed by ridges, which, in some parts of the organ, are 

 quite regular. These are best seen with the aid of a simple lens, as many of them are 



%ff?yff3Sf t *J 



nified 20 diameters. (Sappey.) 



