460 THE DISEASES AND DISORDERS OF THE OX. 



within a few weeks after its formation, the young fluke contained 

 in the cyst will perish. 



It is as well to mention here that infection with flukes may 

 indeed occur at almost any age, but does not usually do so in 

 animals less than three months old. When young lambs become 

 affected, the eggs are probably taken in by their nibbling and 

 playing with the grass. 



Should the grass or other material to which the egg is attached 

 be taken into the alimentary canal of some suitable animal, in 

 about seven weeks' time the contents of the cyst will become 

 developed into the full-grown liver-fluke. The little flukes, pro- 

 tected by their cysts attached to the grass, enter into the 

 stomach, and, passing to the first portion of the small intestines 

 called the duodenum, find their way into the liver, probably 

 through the medium of the bile-ducts. Thus the encysted pupa 

 at length finds it way into the liver, at first into the larger bile- 

 ducts and gall-bladder, and after about seven weeks it arrives at 

 full sexual maturity. Hence, if the pupa gains entrance into 

 the body of a sheep during warm wet days in June or July, as 

 is generally the case, no eggs appear in the droppings until 

 August or September. The adult fluke may live in the body of 

 a sheep one year, and possibly much longer. A sheep affected 

 with liver-rot at first fattens quickly, the entrance of the young 

 flukes into the biliary ducts acting as a local irritant and 

 rendering the liver unusually active, so that a greater quantity 

 of fat is produced and deposited in the tissues. However, on 

 no account should sheep be put on pastures which are liable to 

 give rise to sheep-rot. After a few weeks have elapsed, an 

 infected sheep begins to shrink, the flukes having in that time 

 grown so much as to impede the function of the liver. This 

 organ secretes ineffective bile, and loses its power. The food 

 which, in the process of digestion, flows from the stomach 

 along the small intestine, is imperfectly acted upon by the 

 imperfect bile, and the blood suffers in consequence. If the 

 hips of a sheep infested with flukes are pressed, the sheep 

 winces, and a peculiar crackling sound is occasioned. Again, 

 if an eyelid of a sheep afflicted with sheep-rot be turned 

 well back, and the blood-vessels of the white part and those 

 of the haw be pale or yellowish in colour, then rot may 

 be suspected. The skin of the sheep changes in hue from 



