368 DISEASES OF SHEEP. 



tions, and is becoming rapidly blind. Deatb generally 

 ensues from starvation. 



Veterinary writers and agriculturists have differed very 

 materially as to the cause of hydatid, some attributing it 

 to certain poisonous plants; but these have never been 

 pointed out. Others consider it a species of serous apo- 

 plexy, and others contend that it arises from local weak- 

 ness of the brain, etc., etc. Autopsical examinations 

 have, however, proved it to arise from a different cause, 

 viz : Ccenurias cerebralis, or hydatid in the brain, found 

 floating in a serious fluid, contained within a sac or 

 bladder, thus constituting Sturdy, Gid, Turnsick, etc. 

 It attacks sheep from the sixth to the eighteenth 

 month. 



* " Certainly'' the most common cause consists in the 

 lamb or young sheep picking from the pastures the ova or 

 larvse of the toenia solium^ which infests the shepherd's dog. 

 If Echinococcus, polymorphus or vetrinorium, be swal- 

 lowed by the dog, they are developed into that of tape- 

 worm, with but few serrations. The minute ova are 

 gathered and swallowed with the food of the sheep oi* 

 lamb, and are taken up from the surface of the intestines. 

 They find their way into the blood, and finding a con- 

 venient nidus among the loose textures of the brain, are 

 there deposited. Nature sets to work and encloses these 

 foreign bodies in a membranous sac, so that otherwise they 

 may not produce fatal consequences, and in the short 

 period of three months they are found to have reached 

 the size of a filbert. 



The larvae of the distomum hepaticum found inhabiting 



*Findlay Dun. 



