THE DIGESTIVE SYSTEM. 541 



Haemorrhagic Erosions occur as rounded spots or narrow streaks, 

 formed by a loss of substance of the mucous membrane. The mucous 

 membrane at these points may be congested, soft, and covered by small 

 blood clots. The destruction of the mucous membrane is usually super- 

 ficial, but may involve its entire thickness. The internal surface of the 

 stomach may be studded with these erosions. They give rise to repeated 

 haemorrhages, and are accompanied by catarrhal inflammation of the rest 

 of the mucous membrane. 



They occur at all periods of life, even in infants. Their usual seat is 

 the pyloric portion of the stomach. They may occur independently of 

 other obvious lesions, but are most frequent in connection with chronic 

 congestion of the mucosa, chronic gastritis, in infectious diseases, and 

 intoxications. 



DILATATION. 



Very considerable degrees of dilatation of the stomach are found at 

 autopsies, without stenosis of the pylorus or other mechanical cause to 

 account for them. It is usually difficult to determine how long these 

 dilatations have existed and their influence in the illness or death. 



Acute dilatation of the stomach, with vomiting of very large quanti- 

 ties of thin fluid, has been observed in a few cases, the dilatation being 

 developed suddenly and without discoverable cause. 



Of the mechanical factors which lead to dilatation of the stomach a 

 stenosis of the pylorus is the most common. Such a stenosis may be 

 effected by a tumor, by chronic inflammation and thickening, and by the 

 cicatrization of ulcers. Less frequently obstructions of the small and 

 large intestines act in the same way. 



Some forms of chronic gastritis are attended with dilatation of the 

 stomach without stenosis. 



In rare cases circumscribed, sacculated dilatations are produced by 

 the presence of foreign bodies portion of wood, metal, etc. 



TUMORS. 



Papillomata. It has already been mentioned that in some cases of 

 chronic gastritis there are small, polypoid hypertrophies of the mucous 

 membrane. Besides these we find polypoid tumors which may reach a 

 considerable size. They are composed of a connective-tissue stroma ar- 

 ranged in tufts covered with cylindrical epithelium. In some cases there 

 are also tubules lined with cylindrical epithelium, so that the tumor has 

 partly the structure of an adenoma (Fig. 314). Fibromata of small size 

 are sometimes found in the connective -tissue coat (Fig. 315). Lipomata 

 are formed in the submucous connective tissue in the shape of rounded 

 or polypoid tumors. They usually project inward, but sometimes out- 

 ward beneath the peritoneum. They may also appear in the form of 

 numerous yellow nodules beneath the mucous membrane. 



Myomata occur in the form of rounded tumors which originate in the 



