CCENURUS CEEEBEALIS IN CATTLE AND SHEEP. 355 



more frequent and are more prolonged as the hydatid grows; 

 the rapidity of movement increases until paralysis is induced, 

 and the animal cannot stand. Many tumours and hydatids 

 of a different species to the coenurus cerebralis are met with 

 in the brain, but the peculiar symptoms of sturdy are not 

 induced by them. 



The coenurus consists in a bladder provided with a variable 

 number of exsertile heads, and Dr Davaine believes the ner- 

 vous substance may be excited by the heads, which protrude 

 from the bladder and penetrate the brain substance nearly 

 two lines in depth. Sturdy is, therefore, a phenomenon of 

 excitation of one of the cerebral hemispheres, and Dr Davaine 

 asks if very manifest phenomena of excitation would not 

 result by plunging into the substance of the brain one or two 

 hundred pin-points at a depth varying from one to two lines. 

 As the coenurus increases in age, the number of heads aug- 

 ments, and the points of contact with the encephalon multiply, 

 and in this way Davaine explains the increase in frequency 

 and duration of the vertiginous attacks as the malady ad- 

 vances. 



It is certainly remarkable, that though the echinococcus 

 veterinorum may lodge in the brain of sheep or oxen, it does 

 not produce the characteristic symptoms of sturdy caused by 

 the coenurus cerebralis, and the probable explanation of this 

 is, that the heads of the former are not exsertile, whereas 

 those of the coenurus protrude from the distended cyst. 



The vertigo observed in true sturdy is altogether peculiar; 

 that is to say, the lamb turns round and round, describing 

 concentric circles, and Davaine states that it has been entirely 

 by false analogy that some authors have admitted the exist- 

 ence of sturdy in man. 



Admitting that the coenurus cerebralis exerts a peculiar 

 influence on the brain, it must be remembered that the " run- 



