47- NERVOUS SYSTEM. 



to find two or three vesicles, and in any case the most important informa- 

 tion in regard to diagnosis is to be derived from the ocular sj-mptoms. 



When only one vesicle exists, the turning movement usually occurs 

 towards the side on which it is situated, and the eye of the opposite side 

 is affected with amaurosis. 



If the cyst is situated near the olfactory lobes, the animal marches 

 with a high- stepping movement and the head drawn back towards the 



Pig. 219. — Mheep's skull, the hind portion thin and perforated, due to the 

 presence of gid bladderworms {Ccemirus cerebralis). (After Dewitz.) 



body. If the cyst is in the cerebellum the animal is incapable 'of 

 moving, because it can no longer co-ordinate its movements. Finally, 

 if the cyst develops in the occipital region, animals turn towards the 

 wind, with the neck raised and the head extended. 



At the moment when they fall to the ground they sometimes have 

 epileptiform convulsions, grind their teeth, and salivate profusely. In 

 a severe attack even death may supervene at this point. 



Ccenurosis of the Medulla. The embryos may develop in the 

 medulla oblongata as well as on the brain itself. Compression and 

 atrophy of the medulla then give rise to trae paralysis. 



The animals exhibit paralysis of the hind quarters, unilateral paralysis 



