The Abdomen 149 



noted above the cavity fills up again in three or four days' time. 

 When the condition is secondary to pericarditis or pleuritis the peri- 

 cardium or thorax must also be tapped. 



Numerous cases by Morrison and others are on record in which 

 ascites due to portal obstruction has been overcome by ligaturing 

 the omentum to the chest wall, whereby anastomoses between the 

 vessels are set up and the blood finds its way to the heart without 

 passing through the liver ; but this does not succeed in every case. 



FABACENTESIS. 



For this operation a relatively large trocar and canula should 

 be employed. They should be previously sterilized and the skin over 

 the area of puncture disinfected. This is important because the in- 

 troduction of pyogenic microbes into the peritoneal cavity when its 

 absorptive capacity is inhibited may be followed by rapid infection, 

 the intra-abdominal fluid acting as a highly favorable culture 

 medium. The instrument is introduced at the most dependent part 

 of the abdomen, the animal being made to assume the standing po- 

 sition, and the trocar immediately withdrawn. There is no danger 

 of wounding the intestine as the latter is floating on the surface of 

 the fluid. Only part of the fluid should be removed and that grad- 

 ually as sudden and total removal has been followed by syncope. In- 

 terruption of the flow indicates obstruction of the canula by false 

 membranes or coagula and is corrected by again passing the trocar. 

 When the condition is secondary to pericarditis or pleuritis, the 

 pericardium or pleura must also be tapped. (See Pericarditis and 

 Pleuritis). 



FOREIGN BODIES. 



Three classes of foreign bodies may gain access to the peritoneal 

 cavity. They consist of inanimate objects, verminous parasites, and 

 fetuses. 



Inaoiinate Objects. Comprised in this class are : missiles 

 which have perforated the abdominal wall, bodies which have 

 traversed part of the alimentary canal and finally perforated the 

 gastric or intestinal walls, and surgical requisites such as sponges, 

 which have been inadvertently left in the cavity after being intro- 

 duced during the course of operations. Their presence is not neces- 



