668 Gid. 



towards the interior of the circle lower than tlie other side. Not 

 rarely and especially" in the later stages of the disease tliere is 

 extension of the head (Albrecht). 



The frontal and parietal regions, and the roots of the horns 

 feel warmer than normal and exceptionally the frontal region 

 may bnlge forward (Greve). In animals np to one to one and 

 one half years old, percussion of the cranium, provided the cyst 

 is superficially placed, gives an unusually hollow sound, sim- 

 ilar to that obtained by percussion, immediately below the horn 

 core (Albrecht, Merkt). At the same spot the resistance is 

 elastic. Now and then the roof of the cranium is yielding (Al- 

 brecht), and in many cases the use of the percussion hammer 

 produces sjaiiptoms of pain. 



For percussion of the cranium Albrecht uses a light hammer, but Diem pre- 

 fers one that is fairly heavy and has one end round and the otlier square. Pfab 

 has recently constructed a useful hammer for this purpose. Percussion hammers 

 of the usual type are useful for the discovery of quite superficial cysts. The whole 

 of the frontal region should be percussed with the head extended after the hair 

 has been clipped off. 



As the appetite falls off tliere is gradual emaciation, and 

 if the animal be not slaughtered in time, it finally gets into a 

 condition of complete cachexia. 



In the isolated cases that have been ol)served in horses, the fnnc- 

 tional disturbances have been somewhat severe. In a case recorded by 

 Schwanefeld, there were symptoms of acute cerebro-meningitis (the 

 cyst being on the upper surface of the hemisphere). Frenzel observed 

 emaciation and dilatation of the pupils, and from time to time, circu- 

 lar movements. In Gotteswinter's case, the horse which was previously 

 quiet, became excital)le and vicious, and later showed symptoms of 

 sleepy staggers. In Ziindel's case the disease which lasted four months, 

 started with amaurosis. Later there were attacks of giddiness, while 

 the horse was at work, the head being held to the left and the animal 

 going in the same direction. It was found to be impossible to turn it 

 the other way. The cyst was found in the right hemisphere under the 

 frontal lobe. In addition to these symptoms, rotation, backing and 

 sleepy staggers have been observed, 



Course. Apart from those cases in which the animals die 

 showing symptoms of acute encephalitis at the time of infec- 

 tion, the disease tends to be chronic and last for months. In 

 a proportion of cases, symptoms make their appearance ten to 

 fourteen days after infection, the condition lasting sometimes 

 for a week. These symptoms then disappear, and the charac- 

 teristic symptoms set in after three to six months. In the 

 majority of cases, the disease tends to begin with s^^nptoms in- 

 dicative of pressure on the brain. The length of the interval 

 between infection and the appearance of tlie characteristic 

 symptoms depends upon the severity of the infestation, but the 

 situation of the cysts is not without some influence on this. The 

 subsequent course of the disease depends upon the same factors. 

 There are cases in which the symptoms develop rapidly and 



