DISEASES AND ABNORMALITIES. 147 



born animals the umbilical ring not infrequently appears 

 abnormally large, so that the umbilical cord does not 

 •completely fill it, in consequence of which, the skin and 

 peritoneum either immediately, or in the first few weeks 

 after birth, yield to the pressure of the abdominal 

 <:ontents, and allow the latter to pass through under the 

 skin. ' 



Two forms recognized, viz., congenital, which is 

 apparent -at birth ; and acquired, which appears during 

 the first few weeks afterwards. 



As a rule, a portion of the colon, or caecum, and 

 sometimes of the omentum, is found in- the sac, which 

 is composed of skin and peritoneum. 



Symptoms. — Umbilical hernia is recognized by 

 the presence of a swelling, varying in size from a 

 hazel-nut to that of a man's head, and lying above the 

 umbilicus ; is elastic, soft, sharply defined, and free from 

 inflammatory symptoms. By pressing with the fingers 

 or hand on the swelling, it entirely disappears. Some- 

 times this condition is mistaken for an abscess, so that 

 caution is required before using the knife. Where the 

 umbilical ring cannot be felt, and its complete closure 

 ascertained, every fluctuating enlargement must arouse 

 suspicion of umbilical hernia. When the tumor is not 

 reducible, it is generally due to the accumulation of foecal 

 or other matters in the intestine. 



CAUSES OF ACQUIRED HERNIA. 



Acquired or accidental hernia may be due to severe 

 or sudden muscular exertion on the part of the young 



