43G 3IXJC0US MEMBRANES. 



excentric in position, penetrating into one of the deeper layers of 

 the gastric wall. If we would know the cause of this conical 

 or funnel shape, we must go back to the ha^morrhagic infarction 

 as the starting-point of the lesion. Like every other hiemor- 

 rhagic infarction (of the lungs, kidneys, &c.), this is limited to 

 the area of distribution of a single vessel ; now the vascular 

 territories of the stomach possess the form of shallow, obliquely 

 truncated cones, whose apices are directed upwards in tlie upper 

 half of the organ, downwards in its lower half. This explains 

 how it is that the deepest point of the funnel-shaped crater is- 

 situated, not inider the centre of the hole in the mucous 

 membrane, but nearer its upper or its lower edge as the case 

 may be. 



Another, not less characteristic feature of the simple ulcer, is 

 the exceeding sharpness of its edge, and the absence of any raised 

 border. The nmcous membrane looks as though a hole had 

 been cut in it with a punch. The submucous tissue is as clean 

 and white as though it had been carefully dissected ; and if the 

 idcer perforates it also, the perforation is circular and sharply 

 cut, showing the muscular coat with its transverse bundles as if 

 dissected out. It would seem as though the formative reaction 

 at the base and edges of the ulcer were quite insignificant ; 

 moreover, that the digestive solution followed so closely upon the 

 heels of the plastic infiltration, as to prevent our ever getting a 

 glimpse of the latter at all. The very chronic character of the 

 process, which often drags through more than one decennium, 

 is in favour of the former assumption ; while the latter is sup- 

 ported by the fact that the simple ulcer is only found in the 

 stomach and the upper part of the duodenum, i.e. only in that part 

 of the alimentary canal where its contents are acid, and where 

 the solution of albuminous substances takes place most rapidly. 



§ 375. As regards the further progress of the simple ulcer, 

 the possibility of its cicatrisation has already been referred to. 

 The smaller and more recent the lesion, the sooner may the 

 formation of the "stellate cicatrix" be expected to occur ; i.e. 

 of that minute, white, flattened scar, which replaces a loss of 

 substance perhaps ten times as large as itself, and which must 

 necessarily conti'act and pucker the neighbouring mucous mem- 

 brane. Ulcers of larger size may also become cicatrised, but this 

 does not commonly occur ; when it does, it may lead to such 



