Symptoms. 



665 



ity. It may be anything from two to six or eight to ten days, 

 after which the symptoms, having reached a certain stage, grad- 

 ually disappear, and the animals apparently recover. 



The second stage is preceded by a latent period of three to 

 six months, and as a rule in flocks of sheep no symptoms are 

 observed during this period. Now and then, the disturbances 

 of the functions of the brain are indicated by a certain dullness, 

 especially when the weather is warm or in damp sheds. After 

 the latent period the symptoms which are characteristic of the 

 second stage, gradually develop. 



Disturbances of consciousness are prominent among the 

 general brain symptoms. The animals remain separated from 

 the flock, move with unsteady gait, the feet being lifted high. 

 They stumble along with the head depressed or held high. As 

 a rule, the head is turned around to one side (see flgs. 94 and 

 95) and the animals wdiile standing still, allow the head to drop, 

 or they stand with the 

 forehead pressed against 

 the wall (fig. 93). There 

 is a vacant expression 

 and the appetite is vari- 

 able. Finally the giddi- 

 ness, which results in a 

 stumbling gait, must be 

 referred to disturbances 

 of consciousness. 



In many cases there 

 are convulsions. Indi- 

 vidual groups of muscles 

 may be involved, for ex- 

 ample, the muscles of 

 mastication, causing the 

 animal to grind its teeth 

 and the saliva to froth. 



In other cases, there may be epileptiform seizures. Forced 

 movements may be produced by the disturbances of conscious- 

 ness. These, however, are not constant in nature, and conse- 

 quently are of no value for determining the situation of the cyst. 

 The types of movement vary from case to case. There may be 

 movements in circles, rotation at one place, stumbling, falling on 

 one side, forwards or backwards. 



The veins of the optic disc and the surrounding tissue ap- 

 pear very congested, the arteries on the other hand are con- 

 stricted. There is sometimes edema of the optic nerves and a 

 diffuse cloudiness of the optic disc indicating neuro-retinitis 

 (Bouchut). 



Among the focal symptoms there is sometimes observed 

 squinting, resulting from compression of the nerves of the mus- 

 cles of the eyes, and there are also forced movements which 

 are constant. 



