PARASITIC DISEASES OF THE LIVER. 



299 



the flock, and do not avoid being caught; the cul-de-sac of the 

 conjunctiva becomes filled with mucus ; the temperature presents 

 abrupt variations ; the obstruction to the return circulation pro- 

 duces ascites, bronchial catarrh, etc. In the ox the disturbing 

 symptoms appear very late and the disease rarely ends in death. 

 AVhen slaughtered, we may see considerable hepatic lesions without 

 any manifestation of their existence by any kind of symptom 

 during life. 



Formerly hepatic hypertrophy, detected through the abdominal 

 walls, and the icteric coloration of the mucous membranes and 

 skin, were looked upon as very important manifestations from a 

 diagnostic point of view ; but these two symptoms are oftener 

 wanting than present. We have never seen icterus in this disease, 

 and this is also the experience of Gerlach. Concerning the sensi- 

 tive condition of the liver and the tumefaction of this organ ad- 

 vancing behind the posterior edge of the last rib, these are two 

 phenomena which can only be perceived during the first stage of 

 the disease ; when this is advanced they are seen no longer. A 

 fact which insures the diagnosis is the presence of fluke-worm eggs 

 in the excrements (oval-shapcd eggs, with opercula) ; but in the 

 large majority of cases the existence of distomiasis is positively 

 established by the autopsy. 



It is not unusual to find small numbers of fluke-worms in animals 

 appearing perfectly healthy. 



Course. The course of distomiasis is mainly chronic. Death 

 through cerebral apoplexy (cerebral embolism) is exceptional. 



We may, with Gerlach, accept four stages of the disease : 1. The 

 invasion, soon followed by traumatic hepatitis, by inflammatory 

 tumefaction of the liver; it occurs during the latter end of autumn; 

 it is almost always disregarded during life. 2. Anemia, which ap- 

 pears from six weeks to two months after the opening of the 

 pasture; it is mainly observed from September to November. 

 3. Cachexia, which starts three months after the ingestion of the 

 fluke-worm's eggs ; it is the ultimate stage of the disease; the liver 

 becomes atrophied and œdemas are formed ; this period sets in 

 toward the month of January. 4. The emigration of the fluke- 

 worms, which takes place in May and June, as stated by Gerlach, 

 but which may start much sooner, from the moment when the 

 parasites have reached sexual maturity — that is to say, about three 

 weeks after the ingestion of the eggs. 



