PARASITES OP ANIMALS. 91 



work in the brain, would be trepanning, and that can seldom 

 be effectual, unless the cysts be small and favorably situated, 

 which is not often the case. As with most internal parasites, 

 instead of remedies, we must seek means of prevention. It is 

 very apparent that, in this case, prevention simply demands 

 the absence of dogs that harbor the tape-worms, from all 

 places where the sheep feed or drink. Prevention on the 

 part of dogs can be secured by not allowing them to feed on 

 the offal of slaughter-houses, and especially the heads of sheep. 

 The mature tape-worms can be expelled from dogs by the or- 

 dinary remedies for other tape- worms, some of which are men- 

 tioned under Tcenia mediocanellata. 



Perhaps the most effectual of these remedies is oil or spir- 

 its of turpentine mixed with castor oil. 



Tcenia echinococcus Siebold, of the Dog ; and its young, the 

 hydatid tumors of Man, Sheep, and Cattle. 



This is by far the most important and dangerous of all ces- 

 tode worms. In the mature state it lives in the intestine of 

 dogs and wolves in great numbers, as a very small tape-worm, 

 about an eighth of an inch long, with only three sexual joints 

 or proglottides (Figure 70). In its larval state it forms com- 

 pound cysts and tumors in a great variety of animals. 



Not imfrequently there may be found imbedded in the sub- 

 stance of the liver and lungs of sheep, watery tumors of con- 

 siderable size, sometimes becoming several inches in diameter 

 and causing serious disease, and even the death of the ani- 

 mal. Similar tumors occur, though less frequently, in the 

 brain, kidneys, ovaries, among the muscles, and in various 

 other situations in sheep. They occur also in pigs, horses, and 

 cattle, though less commonly than in sheep, but unlike the Ccen- 

 urus, or " water-brain," these tumors are not confined to the 

 lower animals. They are also found in the human body, and 

 give rise to incurable and most horrible diseases, to which per- 

 sons of ail classes are liable, 110 matter how wealthy or refined. 

 That large numbers of human beings of all ages and condi- 

 tions die annually from diseases caused by this parasite is es- 

 tablished beyond a doubt. And although such diseases are 



