568 THE DIGESTIVE SYSTEM. 



Carcinoma develops most often in the colon and the duodenum. 1 The 

 forms which have been described in the stomach occur also here, i.e.: 1. 

 The medullary forms with relatively little stroma, and epithelial cells 

 either in solid masses within the alveoli ; or maintaining in a measure the 

 gland type adeno- carcinoma. 2. Fibrous form scirrhus. 3. Gelatinous 

 forms, which are more common here than in the stomach. Epithelioma 

 often involves the anus and rectum. 



TUMORS OF THE APPENDIX are rare fibroma, lipoma, myoma, sar- 

 coma, endothelioma, and carcinoma are recorded. 2 Several cases of pri- 

 mary carcinoma of the appendix have been observed. 3 



INTESTINAL CONCRETIONS. (Enteroliths.) 



There are sometimes found in the intestines round, oval, or irregular 

 masses of firm consistence. They are usually small, but may reach the 

 size of a man's fist. They are composed of fsecal matter, mucus, bile, the 

 carbonate and phosphate of lime, and triple phosphate. They may in- 

 duce inflammations, ulceration, and perforation. 



The animal parasites of the gastro-intestiual canal have been already 

 considered in another part of this book. 4 



The Peritoneum. 



Malformations. 



Arrest in development of the peritoneum may be manifested in fissures in the 

 mesial line or external to it ; in absence of the diaphragm ; in fusion with the pleura ; 

 and in incomplete formation of the mesentery, the omentum, and the other folds of the 

 peritoneum. 



Excess of development occurs in the shape of unusual length of the mesentery, the 

 omentum, and the other folds of the peritoneum; or of supernumerary folds and 

 pouches. These are chiefly found in the hypogastric, iliac, and inguinal regions and 

 near the fundus of the bladder. There may be access to these sacs by a well-defined 

 fissure or ring, which is frequently surrounded by a tendinous band lying in the dupli- 

 cature. These may give rise to internal incarceration of the intestines. 



ASCITES. 



The collection of trausudate in the peritoneal cavity may be the re- 

 sult of chronic venous congestion, especially in connection with obstruc- 

 tion of the portal circulation in cirrhosis from thrombi, emboli, etc., or 

 with chronic heart and kidney diseases. It is often associated with 



1 See Rolleston, Lancet, April 20th, 1901. 



2 For bibliography of tumors of the appendix see Kelly, Proc. Path. Soc. of Phila- 

 delphia, n. s., vol. iii., p. 109. 



3 Whipham, Lancet, 1901, vol. i., p. !519. Jessup, Med. Rec., August 23d, 1902. 

 Mosclicowitz, Ann. of Surgery, June, 1903, bibl. Norris, Bull. Univ. Penna., xvi., 1903, 

 p. 334. 



4 For recent bibliography of lesions of the intestines see Thorel, Lubarsch and Oster- 

 tag's "Ergebnisse," Jahrg. v. for 1898, p. 171. 



