474 NERVOUS SYSTEM. 



a needle, which are readily discoverable in the superficial layers. Later 

 these caseous deposits become absorbed, the lesions of disseminated en- 

 cephalitis diminish and disappear, while a certain number of vesicles after 

 partial development undergo atrophy and disappear. Before long nothing 

 remains but local atrophic encephalitis caused by the development of the 

 vesicles, and from this time the central symptoms begin to appear. 



Diagnosis. When the turning movement has developed the diagnosis 

 is generally easy, but it is more difficult during the first period, when 

 encephalitis alone exists; or at least, it is very difficult at this period to 

 discover whether the symptoms are attributable to encephalitis, meningo- 

 encephalitis, coenurosis, tuberculosis, or to some injury. 



Prognosis. The prognosis is grave, and very few animals recover. 



Fig. 221. — Diagrammatic section of a gid bladderworm {Coenurus cerebralis). 

 a, Normal disposition of scolex ; b, c, d, e, diagrammatic drawing to show 

 the homology between cysticercus and coenurus. (After Railliet.) 



Zurn estimated the cases of recovery in flocks at 2 per cent. In these 

 cases the cysts degenerate and disappear. 



Treatment. At the present moment there is no really practical 

 curative treatment. 



The best plan appears to be to trephine the skull and remove the 

 cyst, provided its exact position can previously be determined. That, 

 however, is the great difficulty. Its solution presupposes a perfect 

 knowledge of the central nervous system and of the real purport of 

 any apparent symptoms. 



On the other hand, in sheep at least, the position of the cyst must 

 always remain somewhat uncertain, because there are generally several, 

 and the symptoms are of a mixed character. 



