196 



The Farmer's Veterinary Adviser. 



PARASITIC DISEASES OF THE LIVER. 

 LIVEK-ROT. FLUKE DISEASE. 



This affection is most destructive to sheep, of which it 

 has destroyed as many as from one to two million head 

 in England alone in certain years. It is immediately 

 determined by the presence in the gall ducts of two flat 

 leaf -like parasites — the Fasciola Hepatica and the Disto- 

 mum Lanceolatum — the first | to 1 inch in length, tha 



Fig. 37. 



Fig. 37 — Fasciola Hepatica. 



Fig. 38 — Distomum Lanceolatuin. 



eecond 4 lines. These inhabit the gall ducts of all the 

 domestic animals, of many wild animals and even of man, 

 but in most of these they do little harm. The eggs of 

 these parasites laid in the gaU ducts cannot be developed 

 there, but pass out with the bile and dung, hatch in pools 

 of fresh water in which the embryo floats until it finds 

 a mollusk, in which it encysts itself and becomes a brood 

 capsule developing many new embryos- within it; these 

 embryos may form new brood capsules and thus increase 

 their numbers materially, or if swallowed by a mammal 

 along with its faod or water they develop into the mature 



