DISEASES DUE TO INTERNAL PARASITES. 



203 



In the course of two or three months time they may have at- 

 tained the size of a hazel nut, their presence at that stage seri- 

 ously interferring with the general health of the sheep. Should 

 the head of a sheep infested with these hydatids be fed to dogs 

 these organisms in the brain tissue develop into adult tapeworms, 

 the eggs of which being passed by the dogs on the grasses, etc., 

 and being eaten by the sheep, develop again into hydatids, so 

 completing the life cycle. 



Srain of Sbecp frith Coenurus in poste- Brain of Sheep with four Coenuri 



rior part of Right hemisphere. siniultaneousl>>> 



(COBBOLD.) 



Symptoms. 



The sheep appears dull, out of sorts, grazes in a listless 

 manner, rumination is imperfectly performed, the animal seeks 

 seclusion, its movements are erratic, staggers as it walks, becomes 

 giddy and falls down frequently. Again it may be grazing 

 quietly, suddenly jumps as if frightened, and runs away at full 

 speed. The primary symptoms of dullness and stupor seemingly 

 are due to congestion and inflammation of the brain caused by 

 the invasion of the young parasites, and should the sheep re- 



