NERVOUS SYSTEM. 215 



In so called riding school and clock hand move- 

 ment the coenurus is usually located on the surface of that half 

 of the cerebral hemisphere facing the center of the circle; some- 

 times on the optic thalamus of the opposite side. 



If affected sheep move forward with the head down and trot- 

 ting motion of the forelimbs (trotters) the seat of the parasite 

 is at the anterior end of the hemisphere or on one of the corpora 

 striata. 



Staggering gait, reeling, dizziness (staggerers) indicate that 

 the parasite is located in or on the cerebellum. 



When the coenurus is located at the base of the cerebellum it 

 causes rolling movements of the animal. 



If Ihe animals hold their heads up high or backwards and 

 move forward rapidly, fall down (sailors), the coenurus is located 

 in the posterior portion of the cerebrum. 



c. Disturbances of the muscular sense. The muscu- 

 lar sense enables us to recognize the position of the limbs and 

 the extent of passive and active movements. As long as equi- 

 librium is not affected, an animal suffering from disease of 

 the cerebrum can be made to assume unphysiologic positions 

 without being conscious of it, in fact they do this themselves, 

 they interrupt movements before they are completed or go 

 to the opposite extreme and make more extensive move- 

 ments than occur normally. 



In acute cerebritis and staggers horses sometimes assume 

 peculiar positions of the legs, cross them, set them close to- 

 gether or one before the other ; one may be set unduly forward, 

 the other unduly under the body. When such positions are 

 produced passively the animals make no attempts to change 

 them. In moving about they raise their legs unusually high, 

 (groping, wading walk) or not high enough and thus stumble 

 when they meet obstacles. 



d. Paralyses consist in partial or complete loss of 

 power to bring about muscular contractions. Complete in- 

 ability to move is called complete paralysis; if there is simply 

 diminished power to produce movements we call it 

 incomplete paralysis (paresis). According to the origin of 

 the paralysis we distinguish cerebral, spinal, and peripheral 

 paralyses. Paralysis of one side of the body is called hemi- 



