316 HEALTH AND DISEASE 



draught, jumping, rearing, rolling, and kicking, or it may follow upon 

 some form of external violence, as kicks from other horses, horning by 

 cattle, or blows inflicted upon the abdomen in various other ways. 



Hernia is described as reducible and irreducible. It is reducible when 

 it can be returned into its proper place by simple external manipulation 

 or taxis. It is irreducible when its return cannot be effected without a 

 surgical operation. 



A rupture is said to be stniinjiilated when the orifice through which 

 it passes becomes too small to accommodate the extruded organ without 

 imparting to it considerable pressure, in which case the circulation is 

 interfered with, the blood gathers in the vessels of the escaped viscus, 

 and sooner or later provokes swelling and inflammation in it, which may 

 end in mortification and death of the part. 



EXOMPHALUS OR UMBILICAL HERNIA 



Definition. — An enlargement of the floor of the belly caused by the 

 extrusion of a portion of bowel or omentum through the navel opening. 



In foals it is either congenital or occurs very shortly after birth, in con- 

 sequence of the umbilicus being still pervious or imperfectly closed. In 

 older animals it is usually provoked by blows, some form of severe exer- 

 tion, and especially jumping, rearing, and kicking when at play. It seldom 

 occms niter the age of one year. 



