REDUCIBLE HERNIA. 597 



doughy and its return be more gradual, the hernia is in all pro- 

 bability formed of intestine and omentum. 



IRREDUCIBLE HERNIA. 



A hernia is said to be irreducible when it is not strangulated, 

 but yet cannot be returned into the abdomen. The causes that 

 prevent reduction are : — 1st. The bulk of the protruded parts 

 being out of proportion to the opening through which they 

 would have to return. 2d. Adhesions of the protruded parts to 

 the hernial sac through the medium of organizable lymph, which 

 assumes the form of filamentous bands, admitting of some 

 degree of movement between the intestine and sac, or a more 

 firm union, constituting what has been called " the fleshy union." 

 In this form the union is close, firm, and deep, so that the sac 

 and its contents cannot be separated from each other, but form a 

 solid mass, the circulation of which i« common to both sac and 

 intestines. 



STRANGULATED HERNIA. 



A hernia is said to be strangulated when the contents of 

 the sac experience such a degree of pressure as not only to 

 cause them to be irreducible, but also, by compressing their 

 blood-vessels, to disturb, impede, or suspend the circulation 

 within them. This condition speedily causes inflammation 

 in the protruded parts, which extends to others within the 

 abdomen. 



HERNIiE, AS NAMED ACCORDING TO THEIR SITUATION. 



ExoMPHALOS. — A protrusion of any portion of bowel or 

 omentum through the navel, forming a tumour at that part, is 

 called umbilical hernia or exomphalos. It is very frequently 

 congenital, and is more commonly met with in calves than in 

 foals. If not congenital, it generally takes place very shortly 

 after the birth of the foal or calf, and arises from the yielding 

 of the umbilical opening ; the closure of which, although it may 

 be complete, is still lax and weak. In some cases this laxity 

 and weakness remain until the animal is two or even three 



