342 The Diseases of Animals 



(Sclerostoma armatum) . These worms frequently shut 

 off the circulation of the blood to the intestines, and 

 give rise to acute and violent colic that sooner or later 

 causes the death of the animal. 



There is no method of recognizing this disease before 

 death, but it should be suspected in horses and mules 

 that are subject to violent colic without apparent cause. 

 After death, each dilation of the artery (aneurism) is 

 found to be filled with small worms. There is no 

 satisfactory treatment. 



GID, OR STAGGERS, IN SHEEP 



This disease, which is rare in America, is caused by 

 the presence of a parasite in the brain. The parasite 

 (Ccenurus cerebralis) is the cystic, or larval, form of a 

 tapeworm (Tcenia cwnurus) which infests the dog, 

 wolf and fox. The sheep become infested while pas- 

 turing or drinking where dogs and foxes have scattered 

 the eggs of this tape -worm. After they are taken into 

 the stomach, these eggs hatch, and the larvae bore their 

 way through the tissues until they reach the brain, 

 where they form cysts about half an inch in diameter, 

 filled with a watery fluid in which hang a large number 

 of little balls, or knobs. 



Lambs and young sheep are most liable to infection 

 by these parasites. In the early stages, the animal 

 appears dull, the head is carried in peculiar positions, 

 turned to one side, upward, or drooped toward the 

 ground. The animal has a tendency to walk in a circle, 

 sometimes to the right and sometimes to the left; there 



