193 DISEASES OP THE LIVEE. 



It is frequently the seat of parasitic diseases, notably the nodular 

 disease caused by the oesophagostoma columbianum, which we 

 shall treat of in the chapter on parasitic diseases. Steele says 

 "that simple peritonitis is common in old sheep, resulting from 

 debility, the evidences of which are dropsical swellings, etc." 

 In these cases the destruction of the animals is the best method 

 of procedure, very old sheep not being worth the time and 

 trouble necessary to effect a cure. 



Diseases of the Liver. 



The liver of the sheep is one-twenty-fifth part of the weight 

 of the animal, exceeding in weight the liver of the human being, 

 being proportionately twice as large. Of the diseases affecting 

 the liver of sheep non-parasitic in origin, we shall only describe 

 two as being of sufiicient importance, viz., inflammation of the 

 liver, called "Hepatitis", and jaundice or "Icterus". Diseases 

 affecting the liver, which necessarily interfere with its func- 

 tions, are recognized by the yellow appearance they produce on 

 the visible mucous membranes, especially the lining of the eye- 

 lids (conjunctiva). 



Hcutc Inflatnmation of the Lmr, Rcpatitis. 



This is supposed to arise in the investing membrane of the 

 organ, called the capsule, being virtually its peritoneal covering, 

 originating generally as a result of inflammation in some con- 

 tiguous organ. 



It is most frequently caused by grazing sheep on low-lying 

 pastures, where the growth of grass is high and rank, and is sup- 

 posed to be due to over-nutrition. 



Symptoms. 



The sheep is feverish, the respirations hurried, the visible 

 mucous membranes are of yellowish appearance, due to the pres- 



