The Vet. Book 



becoming infected. Lambs are predisposed to 

 suffer. Some pastures are famed for the pro- 

 duction of it, and as sheep begin to thrive 

 when they are first affected with liver rot, 

 graziers take advantage of this fact, by placing 

 sheep upon it three weeks or so, prior to slaughter. 

 The parasites, evidently, induce an increase of 

 functional power in the liver. 

 Liver rot is due to the presence 

 of fluke-shaped worms, of which 

 there are two species infecting 

 sheep. When mature the liver- 

 fluke is an inch in length, and half 

 an inch in breadth, and of a 

 creamy colour. A single sheep 

 may harbour hundreds of flukes, 

 Adult Liver wn ilst a single fluke may pro- 

 Fig.7— Water Snail duce thousands of eggs. 



(Limnaeatruncuiata} f h e li ver -fluke undergoes a 

 remarkable series of changes, after passing out 

 from the body of the sheep with the ejecta. 



The ova contained in the decomposing liver- 

 flukes have to pass through a series of changes, 

 before completing their cycle of development. 



Briefly put, the embryos pass into ponds, 

 ditches, etc., and become free-swimming by means 

 of minute hair-like processes (cilia), and after a short 

 time the cilia are cast off, and the parasite then pene- 

 trates into the lung cavity of the fresh water snail ; 

 and after a while goes to some other part of the 



102 



Fig. 

 Fluke 



