DISEASES AND ABNORMALITIES. 145 
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 
contents, 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 cecum, 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 fcecal 
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 
