i':::uLiCAL hernia. 723 



comes condensed and organized, forming a fibrous membrane which 

 closes the umbilical opening, and gradually contracting, brings the two 

 edges together ; these unite, and soon nothing is left to mark the situa- 

 tion of the opening, except a short lozenge-shaped fibrous cicatrix : the 

 intestine had previously been retracted within the abdomen, and the 

 urachus, becoming contracted after birth into a thin ligament, while the 

 blood-vessels are obliterated. 



It sometimes happens, however, that the process of cicatrization is 

 either prevented, retarded, or interrupted ; consequently, the umbilical 

 ring remains more or less patent, and certain viscera either remain in it, 

 or are pushed into it by an internal pressure, and lodged in the pouch 

 formed externally by the skin. In this congenital hernia, the vein or 

 veins and the arteries are separated by the misplaced viscera, the former 

 being usually in front, the latter behind. 



The lesion may be observed at the moment the animal is born ; and 

 after the cord is ruptured it may happen that the abdomen remains open, 

 the viscera being exposed ; the creature then generally succumbs quickly. 



Acquired or accidental umbilical hernia usually appears soon after the 

 cord has withered, or within a few months after birth. 



A true and false exomphalus have been described : the first being that 

 just mentioned, in which hernia takes place through the umbilical ring ; 

 while the second occurs through an accidental opening in the neighboring 

 aponeurotic or muscular tunics of the abdomen, and is in reality ventral 

 hernia — occurring, as it generally does, after birth and in adult animals. 

 Various kinds of umbilical herniae have also been alluded to, according as 

 the viscus is intestine or omentum, or both ; thus we have enter omphalus^ 

 mesentero or epiplomphalus, and entero-epiplomphalus. The last is most 

 frequently observed in carnivorous animals. 



Causes. 



We have just alluded to the cause of congenital hernia. Acquired or 

 accidental hernia may be due to severe or sudden muscular exertion ; as 

 when the foal or calf runs or jumps very actively during its gambols or 

 when pursued, or in falls. It is sometimes produced when the young 

 creature is separated from its parent, and being kept in an isolated place,, 

 it rushes about and cries energetically. Umbilical hernia has also been 

 known to follow an attack of colic, and after constipation or diarrhoea. 



There appears to be generally present, in umbilical hernia, a certain 

 organic predisposition, due to the suppressed or imperfect organization of 

 the Whartonian^ gelatine ; and it has been remarked that common-bred 

 animals are more liable to it than those of the higher breeds. Neverthe- 

 less, in all those in which it manifests itself — no matter what the breed 

 may be — there is usually constitutional debility present, due in many in- 

 stances to the mother having been ill-fed and badly cared for during- 

 pregnancy. Zundel says that there are years in which the accident is 

 usually frequent, and particularly ^vhen much rain prevails, as then the 

 food of herbivorous animals is more aqueous than usual. Low, wet, marshy 

 pastures are also believed to predispose to hernia ; as in them the tissues 

 become soft and relaxed, and the digestive organs inordinately bulky ; 

 foals and calves kept in these situations have the belly voluminous, and 

 the extrinsic pressure v/eakens the abdominal walls. Benard, Hamon, 

 Cruzel, Bouley, and others believe in heredity as a predisposing cai>se : 



