Anatomical Changes. Symptoms. 551 



appear healthy from the outside, but if palpated, hard cords 

 can be felt. On section these are found to be dilated bile ducts 

 with thickened and rigid walls. Pressure causes dirty, yellow- 

 ish-brown bile to exude, containing flukes in variable numbers. 

 Similarly altered ducts can sometimes be seen through the cap- 

 sule, especially on the posterior surface, as white firm nodu- 

 lated cords. 



In more severe cases the liver becomes enlarged as a result 

 of the chronic interstitial inflammation which appears later, 

 and its consistency is at the same time firmer. The large bile 

 ducts appear greatly dilated, their walls thickened and hard, 

 and their inner surface is usually roughened by a deposition of 

 salts (calcium phosphate and a little magnesium phosphate). 

 In the lumen of the ducts greenish-brown, viscous bile and large 

 numbers of flukes in various stages of development are found. 

 In a single liver there may be 1,000 flukes or more. At a later 

 stage there is shrinking of the liver, the organ becomes tough 

 and the bile ducts appear as dilated tubes with calcified and 

 thickened walls. Marked glandular proliferation of the mu- 

 cous membrane of the bile ducts is almost always present 

 (Schaper). As a result of repeated invasions various stages 

 of the disease are often discoverable in a liver. 



In severe cases there is usually ascites as well as general 

 wasting and anemia. 



If D. lanceolatum be present in very large numbers (they may 

 number many thousands [Friedberger] ), migration of the parasites 

 may be fohowed by exactly similar symptoms, but as a rule the process 

 is limited to the bile-ducts and the chronic lesions produced are not so 

 severe as those described above. 



According to v. Eatz the calcified nodules which sometimes occur in the livers 

 of horses are due to Hukes. In these nodules Olt found the remains of young 

 eehinocoeci and Mazzantini the embryos of filaria. Morot found distoines m 

 tubercle-like nodules in the xseritoneum, and Cocu in blood-clots on the valves of 

 the right side of the heart. 



Symptoms. Unless the parasites are very numerous there 

 are no functional disturbances, and a moderate invasion may 

 cause no loss of condition. This has been shown over and over 

 again in slaughter houses. 



In acute cases, the period elapsing between infection and 

 the appearance of symptoms is seventeen to tw^enty-one days. 

 In chronic cases one to two months may elapse (Gerlach, Ztirn, 

 and others). 



In the majority of cases, sheep show no symptoms for a 

 month or two after infection, and the first symptoms seen are 

 slight fever, dulness, weakness and anorexia. Careful exam- 

 ination will show that the hepatic region is painful on pressure 

 and that the area of dulness is increased. The posterior border 

 may extend beyond the costal arch and can be palpated (Spm- 

 ola). Anemia due to a reduction in the hemoglobin content 



