96 



DISEASES OF THE DIGESTIVE APPARATUS 



dominal wall, shocks, blows, or by penetration of the abdominal walls, 

 or after some opei'ations and from cold (rheumatic peritonitis). 



Pathological Anatomy. — According to the extent of the disease we 

 call it either partial (circumscribed) or general peritonitis (diffused); 

 according to its course, acute or chronic; and according to its character, 

 we call the exudate serous, fibrinous, purulent, putrid, or hemor- 

 rhagic. The purulent form of the disease is the most common and on 

 account of the extensive irritation that any inflammation causes in the 

 peritoneum, it is apt to take the diffuse form of the disease; and while 

 it may start originally as circumscribed, the disease generally becomes 



Fig. 51. — Section through the abdomen of the dog showing the distribution of the peritoneum: 

 a, kidney; b, aorta; c, vena cava; d, intestine; d' , duodenum; e, pancreatic gland;/, spleen; g, liver; h, 

 subperitoneal fat. 



diffuse in a short time. The peritoneum is first injected and ecchymosed, 

 becoming dull red and velvety, due to the removal of the endothelium 

 and partially to the exudate, which contains more or less fibrinous sub- 

 stances. This collects as a thick layer over the peritoneum and the 

 exudate unites the intestines to each other or to the different organs 

 in the abdominal cavity, or even to the sides of the abdominal wall. In 

 recent cases these adhesions are easily pulled apart, but later on they 

 become firmly united and are very hard to separate (adhesive i^erito- 

 nitis). There is also a quantity of fibrinous exudate thrown out, which is 

 accompanied by more or less liquid. This varies from a small quantity 

 to several litres. There is always some oedema of the serous wall of 

 the intestines, which becomes soft and friable (Fig. 51). 



The chronic form may start out as such at the onset, biit generally 

 it follows an acute attack, the peritoneum becomes very much thickened 



