520 ASCITES. 



instrument may penetrate. In larger animals, 1| to 2 inches may be 

 allowed ; in smaller ones, § to 1 \ inches. As soon as the trocar 

 has entered, the stilette is withdrawn, and the fluid allowed to 

 discharge. Sometimes a check occurs, and the cannula requires 

 to be moved in various directions, or cleared of clots by passing 

 the stilette or a probe. As soon as the fluid ceases to flow, the trocar 

 may be removed, and the wound treated as in operating on the chest. 



In operating on the dog, the animal may be laid on the side, or 

 held in the standing position. Either side may be punctured pro- 

 vided the opening is made close to the middle line. The under surface 

 of the abdomen should be disinfected and the operation performed 

 between the umbilicus and the anterior pubic border, as this position 

 offers less danger of injuring the stomach or liver, which is often 

 increased in size from chronic disease. Not infrequently it is necessary 

 to repeat the operation after an interval of a week or ten days. 



An abdominal bandage, with a small " window," may be applied 

 before operation, so that by tightening it as the fluid escapes intra- 

 abdominal pressure may be sustained and syncope prevented. After 

 operation, bandages prevent further transudation, though unfor- 

 tunately in dogs they can seldom be kept in place. To prevent 

 recurrence of ascites, intra-peritoneal injections of alcohol or solution 

 of iodine, and the administration, per os, of diuretics, like potassium 

 citrate, juniper, digitalis, have been recommended, but this treatment 

 has given little satisfaction. Recently, in man, attempts have been 

 made to modify the portal circulation and thus prevent recurrence 

 of dropsy, by producing permanent adhesion between the omentum 

 and the abdominal wall. 



V.— HERNIA. 



Hernia or rupture is a condition in which portions of the abdominal 

 contents have passed through the abdominal walls, and lie under 

 the skin. Should they pass through the skin, the condition is termed 

 prolapse. The passage of abdominal organs through the diaphragm 

 into the thorax is also described as hernia (diaphragmatic hernia), 

 and in oxen strangulation of the bowel by the spermatic cord is 

 termed pelvic hernia, although in the true sense of the word they 

 belong less to the herniae than to the incarcerations. 



The cause of hernia is sometimes a congenital defect, like too 

 wide an inguinal ring or an open umbilicus. Such hernias are, there- 

 fore, either congenital, or develop soon after birth. Increase of 

 intra-abdominal pressure, frequent coughing, dyspnoea, pressure 



