DISEASES OF SHEEP 559 



eggs, and the segments are discharged with the faeces. These em- 

 bryos fall upon pasture and are taken up by grazing sheep to run 

 another life cycle. 



The bladder worms are likely to cause peritonitis when mi- 

 grating in large numbers from the intestine or liver. The bladder 

 worms that come to the surface of the liver either result in destroy- 

 ing their host or die after a couple of weeks, the location not being 

 favorable for development. Those finding their way into the folds 

 of the omentum seem to cause little inconvenience. The sheep may 

 become infected at any time of the year, preferably during the 

 grazing season, and also from eating hay containing the excreta of 

 dogs. The young sheep are susceptible, but those past five or six 

 years possess a resistance that protects them even against intentional 

 feeding. The diagnosis of the trouble in sheep is difficult to make 

 except by post-mortem. There have been severe losses attributable 

 to this disease, but it is of less importance in this State than in many 

 others. 



The treatment may be wholly preventive. When once the cysts 

 have been formed there is no remedy that can reach them. In the 

 dog the tapeworm may be expelled by suitable remedies. The 

 sheep husbandman must therefore treat the dog, keep off all dogs, 

 and burn or bury carcasses of affected sheep so that dogs will not 

 have access to them. Areca nut powdered, two grains for each 

 pound of body weight, or ethereal extract of male shield-fern are 

 suitable remedies for causing their expulsion from the dog. 



GID OR TURNSICKNESS. 



For over a century claims have been published to the effect 

 that the sheep disease known as gid existed in the United States. 

 Abundance evidence indicates that it certainly has had a foothold 

 in this country for over twenty years. In Montana the range has 

 been infected for at least twenty years, and during that period the 

 infected area has increased until a territory 400 miles long and in 

 places 200 miles wide is infected range. (Bu. An. Ind. Cir. 165, 

 1910). 



Gid is a disease due to the presence in the brain, or, rarely, in 

 the spinal cord of the sheep of a larval tapeworm parasite having 

 the general appearance of a fish bladder full of water. This parasite 

 is commonly known by the scientific name Ccenurus cerebralis, but 

 the correct name is Multiceps multiceps. It is translucent and at 

 times larger than a hen's egg. On this bladder are a number of 

 white objects about the size of a grain of wheat and projecting, usu- 

 ally, into the fluid with which the bag is filled. These objects are 

 tapeworm heads. On feeding this bladderworm, as the gid parasite 

 is called, to a dog, the bladder digests, but the tapeworm heads pass 

 on to the intestine, where they add segment after segment back of 

 the head, till in the course of a month or two each head has become 

 the head of one of the familiar segmented tapeworms, the worms in 

 this case becoming 2 or 3 feet long. Having attained this size, the 

 posterior segments, which contain hundreds of very small tapeworm 

 eggs, begin to break off and are passed out onto the range or pasture 



