308 DISEASES OF THE LIVER. 



(arteries and veins), some of the injected matter will be fomid a day 

 afterwards in the digestive apparatus of the parasites. 



The disturbances which they produce are therefore due to their 

 actual presence and its consequences, to their mode of life, and to the 

 intercurrent infections of which they are sometimes the initial cause. 



It is idle to object that the part played by these parasites is less 

 important than has been suggested, and that the mortality results from 

 intercurrent infection, and not from the parasites themselves. It is 

 equally idle to point out that carcases of animals suffering from severe 

 infection with distomata, particularly the carcases of sheep, are frequently 

 found in slaughter-houses, in perfectly fat condition, and with the appear- 

 ance of not having suffered in any way. These observations are perfectly 

 correct and well founded. But it matters little that death results from 

 an infection superadded to the distomatosis, if the presence of distomata is 

 the determining factor in causing the superadded infections, and if such 

 infection is, as Moussu believes, almost inevitable in animals already 

 exhausted by the action of the parasites. 



The fact that animals suffering from distomatosis and slaughtered for 

 food are well nourished is not a valid objection ; for it has long been 

 known that wasting and anaemia are not immediate consequences, and 

 that before they are clearly apparent the distomata must have been 

 present in the liver for several months. Bakewell and the Marquis 

 of Behague have shown that in moderately infected animals there is 

 a tendency to lay on flesh during the first and a portion of the second 

 stage of development of the disease. 



If the animals are slaughtered before the period of progressive 

 decline sets in, it is quite possible to form entirely wrong views regard- 

 ing the importance of these parasites. 



The wasting process commences towards the end of the second phase 

 of the disease, and then makes rapid progress. The parasites, which 

 have then been continuously drawing on the blood for their nourishment 

 for a long time, produce anaemia, and some infection of the bile ducts, 

 and usually a certain degree of icterus. 



The third phase is accompanied by general signs of cachexia, which 

 need not again be described. They are similar to those of all pro- 

 gressive cachexias. In animals which survive this phase and are 

 ultimately slaughtered the liver always shows very marked sclerosis, 

 commencing around the biliary ducts. Even after the parasites have 

 been evacuated, these ducts appear indurated, thickened, fibrous, and 

 sometimes encrusted with biliary deposits or obstructed with true calculi. 

 These calculi may or may not contain parasites ; sometimes they simply 

 contain eggs : they are open, tubular, and perforated, but always irregular 

 on the surface. 



