THE HOESE. 



101 



vessels going to and from the stomach and 

 spleen would remain uncovered, the anterior 

 part of the transverse colon, the anterior 

 surface of the pancreas, and inner or pos- 

 terior layer of the gastro hepatic omentum. 



Next to be described to the serous coat 

 is the muscular one, which is constituted of 

 involuntary plain fibres, whose thickness is 

 very variable in different subjects, as well as 

 in different parts of the same stomach. 

 The cardiac end is more muscular than the 

 pyloric, except at the right margin of the 

 latter, where it is very powerful and thick, 

 as it smTounds the pylorus. The thinnest 

 part of the stomach is unquestionably the 

 convex border of the lesser cul-de-sac. 



The muscular coat of the stomach is in- 

 tricately arranged, and authorities differ 

 vastly from each other in the description of 

 the several layers constituting it. The 

 number of layers entering into its compo- 

 sition is three : the outer and inner ones are 

 mostly continuations of the inner layers of 

 the cEsophagus, while the middle one is pro- 

 per to the stomach. 



The outer layer is composed of the 

 longitudinal fibres of the oesophagus : as 

 these reach the cardiac end of the stomach, 

 they form a peculiar turn, whereby the dis- 

 tribution on the surfaces as a flat layer is 

 facilitated. Some of the fibres of this layer 

 dip down to join the deeper ones, while 

 others continue onwards as the longitudinal 

 fibres of the duodenum. As to the fibres 

 which proceed on to the curvatures, they 

 are not so intricate, as they descend directly 

 from the portion of the oesophagus opposite 

 the part they supply, so that the only alter- 

 ation in direction is that of diverging a lit- 

 tle from each other, and pursuing the bent 

 course of the corresponding gastric curva- 

 ture. On the lesser one they soon become 

 scanty, and are lost in the circular fibres of 

 the body of the* stomach : very few of them 

 are traced on to the pylorous. The fibres 

 proceeding on to the greater cm'vature are 

 mingled with other considerable bundles 

 taking the same direction, but which are not 

 traceable on to the oesophagus, as they seem 

 to pass round each side of the cardia, and 



blend with the circular fibres on the lesser 



curvature. 



The middle layer consists of annular 

 fibres, which, though scanty as they encircle 

 the extreme left end of the stomach, increase 

 in bulk towards the middle part of the 

 organ, and are especially developed at the 

 lesser curvature. They again decrease over 

 the antrum pylori, but are ultimately greatly 

 developed for the formation of a powerful 

 sphincter at the pylorus. 



The internal or oblique fibres of the 

 stomach have somewhat the same arrange- 

 ment as the deep layer of fibres of the 

 oesophagus, although not perfectly identical, 

 as they are arranged like hoops placed one 

 within the other ; but while in the former 

 the one set enters the other without inter- 

 section, in the latter there is a partial decus- 

 sation by separate bundles. Thus, in real- 

 ity, the oblique fibres of the stomach are 

 constituted of two layers, the one proceed- 

 ing from the left end of the stomach on to 

 the right, which pass internally to the next 

 layer : this one proceeds from the right of 

 the cardia on to the fundus. Owing to the 

 scantiness of circular fibres at the base of 

 each cul-de-sac, the fibres are here in con- 

 tact with the superficial longitudinal ones. 

 The oblique fibres are best studied by dis- 

 secting from within, and, after removing 

 these, the circular fibres come into view 

 with greater case than by attempting to 

 expose them from without. 



The third coat of the stomach consists 

 merely of the cellular tissue existing be- 

 tween the muscular and mucus coats, as 

 well as connecting the former to the outer 

 serous tunic, in which case it is more abund- 

 ant and firm nearest the curvatures. There 

 it is situated between the muscular and mu- 

 cus coats : it was named by the ancients, 

 on account of its white aspect, the Tunica 

 Nervosa. It is loose in some parts and 

 firm in others ; not only serving to connect 

 parts together, but also to form a medium 

 in which vessels ramify for the supply of 

 the organ. 



The internal or mucus coat of the stom- 

 ach differs in the cardiac from the pyloric 



