490 HERNIA. 



The consequent disturbances are more or less marked and the 

 lesions more or less variable, according to the part affected. In the 

 lower region fissure of the abdominal wall aftects the rectus abdo- 

 minis, obliquus abdominis and transversus abdominis, and on the right 

 side gives rise to hernia of the abomasum or small intestine, on the 

 left of the rumen. In the lateral regions muscular fissures can be 

 produced only in the transversus and obliquus abdominis muscles. 

 Hernia of the rumen is rare on the left side. On the right side hernia 

 of the intestine is more readily produced. 



In all cases where hernia is suspected, the hernial orifice should be 

 examined. Its situation will at once show which organ is affected. 



Spontaneous hernia are very rare in the domesticated animals. 

 They occur only in aged animals, and various reasons have been suggested 

 to explain their appearance. Certain hernife of this character are only 

 found in obi female animals which have borne a considerable number of 

 young. Eepeated gestation produces elongation and relaxation of the 

 muscular fibres from the wei.i^ht of the foetus and its envelopes. In time, 

 the abdominal walls become thinner and thinner under the weight of 

 the viscera, and thus facilitate the slow formation of a hernia. Certain 

 practitioners consider that some of these spontaneous hernije are due 

 solely to the i^ressure produced by the distended viscera, as for example 

 in greedy-feeding animals. In such cases the weight of the viscera 

 would cause, as in the previous case, a certain degree of anaemia and 

 emaciation of the abdominal muscles. 



These spontaneous ventral hernite are due in reality to changes in 

 the nutrition of the abdominal wall, the exact cause of which it is diffi- 

 cult to ascertain. The elastic tunic becomes atrophied, and ceases to act 

 as an automatic girth ; the muscular wall gradually becomes sclerosed 

 from the white line tow'ards the sides, and having lost its elasticity 

 becomes distended and thinned. 



These changes are not exclusively caused by old age, for they may 

 be found even in young animals. 



Nothing can be done in cases of spontaneous hernise. The qualities 

 originally pertaining to the abdominal wall canirot be restored, and 

 treatment is confined to applying suspensory bandages, and, where pos- 

 siljle, preparing the animals for slaughter. 



HERNIA OF THE RUMEN. 



Causation. Hernia of the rumen is, as a rule, of traumatic origin, 

 and always occurs. in the left flank, either in the lower or middle regions. 

 Cases of spontaneous hernia of the rumen have been observed in very 

 old and aneemic animals, as well as in females which have borne mai:iy 



