470 



NERVOUS SYSTEM. 



Symptoms. First phase. — Disseminated eneejjJialitis. — The symp- 

 toms vary with the phases of evolution of the parasite and of the disease 

 which it causes. After the six-hooked embryos have penetrated to the 

 brain, the animals affected lose appetite and show a certain degree of 

 dulness, which is all the more marked inasmuch as the animals usually 

 affected are young, and therefore should appear bright and alert. Then 

 follow wasting and depression ; the animals remain stationary for whole 



Fig. 216. — An adult gid tapeworm 

 {Tcenia ccenurus). Natural size. 

 (After Eailliet.) 



Fig. 217. — Sexually mature segment of 

 the gid tapeworm {Tcenia ccenurus). 

 cp, Cirrus pouch ; gp, genital pore ; n, 

 nerve ; ov, ovary ; sg, shell gland ; t, 

 testicles; tc, transverse canal; ut, 

 uterus ; v, vagina ; vc, ventral canal ; 

 vd, vas deferens ; vg, vitellogene gland. 

 X 20. (After Deflfke.) 



hours together, the head being carried low or inclined to one side. At 

 this stage disturbance in vision and irregularities in movement may 

 appear. 



The eyesight is almost always affected, but the symptoms may vary 

 widely. In some cases the patients seem to be absolutely blind, and 

 strike against any obstacle in their way ; in others the power of vision 

 seems to be lost only on one side. All that can be discerned objectively 

 is an inequality in the pupils, together with retraction or dilatation, con- 

 vergent or divergent strabismus, nystagmus, etc. The humours of the 



