Anatomical Changes. Symptoms 



663 



stroyed, and tlie basal ganglia flattened. In some cases, one 

 hemlpl ere may be entirely replaced by a cyst. Exceptionally, 

 rhyda'id is q'^nte free in the excess of flnid m the lateral ven 

 tricle( Bering 'Hntvra & Marek) and may pass from there 

 throngh tlie fommen of Monro into the ventricle of the opposite 

 side o'r into the third ventricle. +i,^ ^lo 



Cvsts on the surface of the hemispheres may canse the de- 

 strnction of the roof of the craninm immediately over them 

 tvo cases Hntyra & Marek), and even of other por ions, gener- 

 a Iv the frontal or parietal bones. In sncli cases the bone be- 

 comes as thin as paper and qnite translncent, or tj- >one tissne 

 mav quite disappear over a circular area, leaving the cyst cov- 

 ered only by the membranes of the bram, the periostenm, and 

 the soft tissues over the cranium. 



Out of 100 cases Kolb found the cyst in 32 cases on the left side, 68 on the 

 right, and in 5% of cases in the cerebellum. 



In rare cases, the cysts develop in the vertebral canal (see 

 compression of the spinal cord). 



In cattle the cysts sometimes attain the size of an orange, 

 and there may be a number present (Vollrath found twenty- 

 three, and Pfab sixty). They may be the cause of exactly sim- 

 ar iLsions of the brain and also of atrophy of the roof of the 

 cranium. If they are situated under the frontal bone in calves 

 fhev n ay perfo/ate the still single layer of bone; but m older 

 an'mals, the inner layer is forced outwards and the frontal 

 mis is'completely obliterated. The outer wall may also appear 

 to bulge outwards (Greve), or may even be atrophied over a 

 circular area (Pfab). 



In the horse, as a rule, only single cysts are found, either on 

 the upper surface of one of the hemispheres, or ma lateral 

 wntricle. They have been found in one case between the hemi- 

 spheres and the cerebellum, and in one case m both hemispheres^ 

 In animals that have been ill for some time, symptoms ot 

 anemia and cachexia are generally seen. Sometimes, one sees 

 in t^e thoracic or abdominal wall, or in the oose connective 

 tissue small rounded greenish-yellow nodules about the size ot 

 a pea On section these are found to contain a pu p-hke mass 

 enclosed in a membranous envelope which in all Probability rep- 

 resents the remains of dead embryos (Roll, Neumann) l^xcep- 

 tionally well-developed hydratids ^-^y^l^^-^l^^l^^.^^^^.f;^^!^ 

 taneous connective tissue (Natlmsms, Eichler), m the thyioid 

 and in the muscles (Rabe). 



Symptoms. In the sheep two stages separated by a long 

 interval are recognizal)le during the course of the disease. The 

 first stage is cerebro-meningitis, set up by the migrations ot 



