278 HYDATID ON THE BEAITT. 



hydatis polycephalus cerehralis, which signifies the many- 

 headed hydatid of the brain ; these heads being irregularly 

 distributed on the surface of the bladder, and on the front 

 part of each head, there is a mouth surrounded by minute, 

 sharp hooks within a ring of sucking disks. These disks 

 serve as the means of attachment by forming a vacuum, and 

 bring the mouth in contact with the surface, and thus by the 

 aid of the hooks the parasite is nourished. The coats of the 

 hydatid are disposed in several layers, one of which appears 

 to possess a muscular power. These facts are developed by 

 the microscope, which also discovers numerous little bodies 

 adhering to the internal membrane. The fluid in the bladder 

 is usually clear, but occasionally turbid, and then it has been 

 found to contain a number of minute worms." 



According to Mr. Youatt, this disease attacks many of the 

 weakly lambs in the English flocks. It usually appears, he 

 remarks, " during the first year of the animal's life, and when 

 he is about or under six months old." It succeeds "a severe 

 winter and a cold, wet spring." He says : 



" If there is only one parasite inhabiting the brain of a 

 sturdied sheep, its situation is very imcertain. It is mostly 

 found beneath the pia-mater, lying upon the brain, and in or 

 upon the scissm-e between the two hemispheres. If it is 

 withiii the brain, it is generally in one of the ventricles, but 

 occasionally in the substance of the brain, and, in a few 

 instances, in that of the cerebellum. * * * This is a 

 singular disease ; but it is a sadly pi'evalent and fatal one in 

 wet and moorish districts. * * * It is much more fatal 

 in France than in Great Britain. It is supposed that nearly a 

 million of sheep are destroyed in France every year by this 

 pest of the ovine race. * * * The means of cufe are 

 exceedingly limited. They are confined to tne removal or 

 destruction of the vesicle. Medicine is altogether out of the 

 question here." 



Many barbarous methods have been adopted to rupture 

 the hydatid. Mr. James Hogg thrust a wire up the nostrils 

 of the sheep, and through the plate of the ethmoid bone into 

 the brain, and thus, as he assures us, punctured the hydatid 

 and "cured many a sheep!"* This practice, which I can not 

 characterize otherwise than as atrocious, is justly condemned 

 by Mr. Youatt. Mr. Parkinson " pulled the ears very hard 

 for some time," and then cut them off close to the head ! f 



* Hogg on Shoep, p. 59. 



t Parkinson on Sheep, Vol. 1, p. 412. 



