Parasites of the Liver. 347 



Distomatosis of the Liver, Liver Rot. Fluke disease. 

 Cachexia Aquosa verminosa. Rot dropsy. Xachexia- 

 ictero-verminosa. 



Definition. A parasite disease of the liver of sheep and other 

 animals, due to the presence in the gall ducts of two species of 

 trematodes — distonia hepaticum, and distoma lanceolatum, and 

 manifested by progressive anaemia, emaciation, icterus, dropsy 

 and marasmus. 



The essential cause is the presence in large numbers of the par- 

 asite, yet in the advanced stages the illness persists, even to a 

 fatal issue, though the distoma has reached the limit of its life 

 and has disappeared. 



Distoma Hepaticum. Fasciola Hepaticum. Liver 

 Fluke. This trematode is a flat, leaf-like, brownish parasite, 

 oval, broad in front and narrowing gradually to the tail, which 

 is rounded ; •length ^ to i inch ; breadth 5 to 7 lines. The 

 head is conical with a small, round, oral sucker at its sum- 

 mit. The ventral sucker, just back of the neck, is large with a 

 triangular opening, and just in front of this is the genital orifice. 

 This skin is covered with scaly spines inclined toward the tail. 

 Back of the ventral sucker in the median line is the uterus with 

 the oviducts on each side. Still more posteriorly is a white area 

 representing the testicles and vasa deferentia. The penis is 

 curved and projects from the genital pore. The digestive system 

 is represented by two lateral canals connecting in front with the 

 oral sucker and gullet, and giving off numerous ramifying 

 branches toward the lateral margins of the body. The alb'umi- 

 niferous ducts are placed more laterally and run longitudinally 

 with branches passing out toward the borders of the fluke. The 

 eggs are brown, oval, -^^ by ^-fg- inch, with a lid or operculum at 

 one end which opens to allow the exit of theiembryo. 



Biology. DevelopmeJit. The life history of the trematodes has 

 been especially ellucidated by Steenstrup, Creplin, Pagenstecher, 

 Ercolani, Leuckart, Baillet and above all by Thomas. The par- 

 thenogenesis or encrease in numbers by asexual larvae, and the 

 successive hosts and media of the immature distoma, are as 

 follows : 



I. The unsegmented ovum in the oviducts and womb ; the 

 segmented ovum in the bile ducts, intestines or pools of water. 



