GENERAL REMARKS 249 



absorption, removing inert bodies and also microorganisms 

 from the peritoneal cavity. The omentum is, further, an 

 important factor in preventing peritonitis, in that it removes 

 the microorganisms from the abdominal cavity before they 

 can produce their pathogenic action. The omentum also 

 has the great faculty of localizing inflammation and infection 

 by attaching itself to any inflamed organ or possible source 

 of infection. It becomes fixed around the margin of the 

 inflammatory or infected area, where it adheres, preventing 

 generalization. The omentum is an important protective 

 mechanism after surgical work on the organs in the abdominal 

 cavity. Another point worthy of mention is the fact that 

 abscesses which develop following operations, puncture of 

 abdominal walls, etc., usually open to the outside rather than 

 in the abdominal cavity, due no doubt to the great defensive 

 powers of the peritoneum as compared to the other tissues. 



The visceral peritoneum is not very sensitive to pain while 

 the parietal is very sensitive. Therefore, the reason for 

 extreme sensitiveness to pressure over the abdomen in acute 

 peritonitis. The visceral peritoneum even in inflammatory 

 conditions is not very sensitive. The natural resistance of 

 the peritoneum varies greatly in the different animals. The 

 dog seemingly has the greatest resistance, and, therefore, 

 abdominal surgery can be practised on this animal with a 

 much greater degree of safety than in other animals. The 

 cat is slightly less resistant than the dog. However, it must 

 always be remembered that there is a great variation in the 

 natural resistance of individuals of the same species depend- 

 ing to a great extent upon their physical condition, etc. 



As a summary, the defensive powers of the peritoneum 

 are of great importance and are: (a) Its great absorbing 

 power, removing organisms before they can multiply suffi- 

 ciently, produce toxins, and excite inflammation, (b) The 

 phagocytic action exerted by leukocytes, polymorphonuclear 

 leukocytes and the endothelial cells, (c) The faculty of the 

 omentum in walling off local infections and inflammations 

 preventing diffuse peritonitis, (d) The antitoxic and 

 bactericidal properties of the peritoneal fluid. This fluid 

 is increased when necessary. 



