352 THE «'I'OMACH. 



the pylorus, becomes continuous with the longitudinal fibres of the 

 duodenum. 



The second set consists of the circular fibres (fig. 245, mi, fig. 24C, b), 

 ■which form a complete layer over the whole extent of the stomach. 

 They commence by small and thinly scattered rings at the left extremity 

 of the great cul-de-sac, describe larger and larger circles as they sur- 

 round the body of the stomach concentric to its curved axis, and 

 towards the pyloric end again form smaller rings, and at the same time 

 become much thicker and stronger than at any other point. At the 

 pylorus itself, they are gathered into an annular bundle (fig. 245 in 

 section), which projects inwards into the cavity, and forms, within 

 the annular fold of mucous membrane, the pyloric sphincter. Some of 

 the circular fibres appear to be continued from those of the oesophagus,, 

 spreading from its right side. 



The innermost muscular layer is incomplete, and consists of the 

 oblique fibres (fig. 246, c). These are continuous with the circular fibres 

 of the gullet ; they embrace the cardiac orifice on the left, where they 

 form a considerable stratum and from that point descend obliquely 

 upon the anterior and posterior surfaces of the stomach, where they 

 spread out from one another, and taking the direction of the circular 

 fibres, gradually disappear. A similar set of fibres are noticed by Henle, 

 and more fully described by Petti grew as proceeding from the right side 

 of the cardia and spreading over the front and back of the gi-eat cul-de- 

 sac : these arc in part continuous with the circular layer. The oblique 

 fibres are best seen from the inside of the stomach, after removing the 

 mucous membrane. 



The areolar or submucous coat of the stomach is a distinct layer 

 placed betw'een the muscular and mucous coats, and connected with 

 both : it consists essentially of areolar tissue, in which occasional 

 fat-cells may be found ; and it is the seat of division and passage of 

 the blood-vessels. 



The internal or mucous coat is a smooth, soft, rather thick and 

 pulpy membrane, which has generally a somewhat pink hue owing to 

 the blood in its capillary vessels, but after it has been well washed, 

 is of a greyish white or pale straw colour. In some cases, however, 

 it presents this pale aspect without any previous washing. In infancy 

 the vascular redness is more marked, the surface having then a rosy 

 hue, but it becomes paler in childhood, and in aged persons is often 

 of an ash-grey colour. During digestion its vessels become congested, 

 and when examined in that condition it is always of a much brighter 

 pink than at other times. 



Alter death a few hours often suffice to change its colour to a dixty bro-nii tint, 

 mottled and streaked in some cases with dull red lines, con-esponding with the 

 coui'se of the veins. This alteration is owing- to the exudation of the colouring 

 matter of the blood, and is especially met with in old subjects, in whom the 

 mucous membrane is always thin. In acute inflammation, or after the intro- 

 duction of irritating substances or of strong acrid poisons, it becomes of a bright 

 red, either all over or in spots, patches or streaks of variable sizes. CoiTOsive 

 poisons, the gastric juice, and sometimes regiu-gitating bile, may stain it variously, 

 black, brown, yellow, or gi'een. As was pointed out by Yelloly, in cases of 

 obstracted venous circulation, as when death occurs from hanging or from 

 drowning, and from certain diseases of the heart, the surface of the stomach is 

 reddened ; but the amount of vascularity may vary also from cii'cumstanccs 

 which are not well understood. 



