1904.] 



Sturdy or Gid in Sheep. 



295 



very small, may become in two or three months as big as 

 a hen's egg. Its outer coating is very thin and more or less 

 distended by a limpid colourless fluid. The parent cyst develops 

 on its surface scolices or larva, 100 to 200 in number ; these 

 appear as groups of white spots about the size of a millet seed, 

 and each consists of the head of a future tape- worm and matures 

 as such if, when the sheep dies or is operated on, the brain con- 

 taining them, or the cyst itself, is thrown away and eaten by a dog. 

 When this happens each larva of the tape-worm separates itself 

 from the mother cyst in the intestine of the dog, where it becomes 

 fixed in the mucous membrane and develops into the tape-worm 

 as before described. 



A diseased sheep may appear easily excited and very timid 

 when approached, or it may be dull and stupid. Usually it is 

 seen apart from the rest of the flock, walking about unsteadily 

 and frequently turning round in a circle. It is seldom at rest 

 for any length of time, and if disturbed may try to run away, 

 but can only move helplessly round in one direction, often with its 

 head carried unevenly on one side. In advanced cases the sheep 

 may become blind. The symptoms vary, however, according to 

 the position and size of the cyst. If it is near the surface of the 

 brain and on one side, which is the most usual position, the 

 affected animal walks round towards that side. If the cyst 

 exists on both sides, it will circle to one side or the other at 

 different times. If the cyst is situated in the middle the sheep 

 raises its nose and walks straight forward, only stopping, 

 as a rule, when it knocks up against something. If the cyst 

 is lodged in the back of the brain, the head is raised and the 

 sheep stumbles forward with a jerking uncertain motion of its 

 limbs, breaking into a sort of shambling run, ending in a fall 

 and a violent struggle to get up. 



If left to itself the affected sheep refuses to eat, and by the 

 combined effects of starvation and almost constant movement 

 it wastes rapidly away and dies. Sheep over two years' old 

 and those that are strong and in good condition are rarely 

 affected. 



As a preventive treatment it is desirable not to keep more dogs 

 than are necessary to tend the flock. In the springtime of 

 each year the dogs should be tied up for a few days and given 



