PROGNOSIS OF UMBILICAL HERNIA. 531 



skin and peritoneum, and which varies in size from a hazel-nut to 

 that of a man's head. 



Causes. This condition is always due to abnormal size of the 

 umbilical ring. The larger this is the more easily does hernia occur. 

 This explains the hereditary character of umbilical herniae, as observed 

 by Viborg and Eleonet in horses, and Benkert in dogs (Stockfleth). 

 In some congenital cases, the herniated viscus has never been in 

 the abdominal cavity, because it has not been surrounded by the 

 visceral plates. After birth, umbilical hernia results either from 

 over-stretching of the skin covering the umbilicus, e.g., from violent 

 tearing away of the umbilical cord ; or it may be caused by any 

 circumstance producing increase of intra-abdominal pressure, such 

 as tympanites, excessive action of the abdominal muscles during 

 constipation {e.g., atresia ani), severe exertion and continuous 

 coughing. It seldom develops in old animals. 



Symptoms. Umbilical hernia is recognised by the presence of 

 a swelling of the size above mentioned, which lies below the umbilicus, 

 is elastic, soft, sharply defined, and free from inflammatory symptoms. 

 It usually takes the form of a larger or smaller hemisphere, and seldom 

 possesses a neck. By thrusting one or two fingers upwards into the 

 swelling, the umbilical ring can be discovered in the depth. Some- 

 times it scarcely admits a finger, sometimes the entire hand can be 

 thrust into it. By laying the animal on its back, or pressing on the 

 swelling with the open hand, it disappears. 



No mistake can well occur, except in young animals with in- 

 flammatory disease of the umbilicus ; but caution is required in 

 using the knife, because such hernia? have often been incised with 

 the idea that they were abscesses. Where the umbilical ring cannot 

 be felt, or its complete closure ascertained, every fluctuating swelling 

 at this point must arouse suspicion of umbilical hernia. In dogs, 

 and occasionally in oxen, a swelling the size of a walnut is seen in 

 the umbilical region. It is not a hernia, but is due to thickening 

 of the subcutis, or to remnants of the umbilical cord, which has 

 ruptured or been divided at too low a point. The swelling is not 

 affected by pressure, and the umbilical ring is closed. In oxen this 

 thickened tissue sometimes becomes inflamed and suppurates. 



Prognosis. This depends, first, on the size of the umbilical 

 opening, and then on the size of the sac and the age of the animal. 

 Spontaneous recovery is common, and is favoured by small size 

 of the rupture, absence of adhesions and youth of the animal. In 

 herbivora a small umbilical hernia generally disappears as soon as 

 the animal begins to receive solid food, which produces distension 



