349 The Diseases of Aninials 
(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 
(Cenurus cerebralis) is the cystic, or larval, form of a 
tapeworm (Tenia cenurus) 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 larve 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 
