^208 PARASITES OF THE DOMESTIC ANIMALS 



there were more than twice this number. The lesions produced will 

 differ according to the development attained by the parasites at the 

 time of the examination. Primarily the lesions are disseminated, and 

 the small cysts may be found at various places upon the convex surface 

 of the brain, surrounded by a yellowish exudate, granules, and cal- 

 careous particles, while, in the vicinity, there may be a small hem- 

 orrhagic area. In cases which have presented the characteristic symp- 

 toms of turnsickness, or gid properly so-called, but one large vesicle of 

 advanced development is ordinarily found (Fig. 116). Such cysts are 

 usually located upon the surface of the cerebral hemisphere, where, 

 by their pressure, they produce an ansemia and softening of the cortical 

 substance. In old cases with large cysts situated upon the brain's sur- 

 face the constant compression upon the roof of the cranium may, by 

 absorption, bring about thinning of the bone to such a degree that it 

 will yield to even comparatively slight pressure of the fingers. 



Exceptionally, the coenurus may be found free in an excess of fluid 

 in a lateral ventricle, and, again rarely, exploration of the vertebral 

 canal will reveal a cyst in the lumbar or cervical region, or it may be 

 at the medulla oblongata. Such cysts are much elongated, and usually 

 there is but one. At the cyst's location the medullary substance is 

 atrophied and softened. Such muscles as may be secondarily involved 

 show the alterations of atrophy and cachexia. 



Symptoms. — As may be inferred from the foregoing, the symptoms 

 presented in coenurosis will be conditional upon the age of the infection 

 and the size attained b}^ the cysts, and also upon their location, the 

 latter factor furnishing the two forms of the affection, — the cephalic, 

 when located in the brain, and the medullary if in the vertebral canal. 



If the parasites are few in number, there will be no symptoms during 

 the early stages, or the^^ may be slight and unnoticed. If there is a 

 heavy invasion the cerebral disturbances caused by the migrations of the 

 parasites may be manifested as stated below. According to Moller, 

 however, these primary symptoms are not observed in four-fifths of 

 the cases. 



Early in the infestation there is dullness, somnolence, inappetence, 

 and usually a rapid loss of flesh. Visual disturbance is soon noticed, the 

 animal colliding with objects which it is apparently unable to see. 

 Examination of the eyes at this time will show a congestion of the 

 sclera; later there is strabismus with either convergence or divergence, 

 and the pupils may be unequally dilated. There are concomitant 

 troubles of motility, and, as the disease progresses, the animal frequently 

 falls down or may assume a recumbent position for the entire day. 

 If it becomes unable to rise, it is probable that death will soon follow. 



When these early symptoms occur, they generally first appear ten 

 to twenty days after infection and persist for a variable period of two 



