PARASITES OF ANIMALS. OL 
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 meaus 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 Tenia mediocanellata. 
Perhaps the most effectual of these remedies is oil or spir- 
its of turpentine mixed with castor oil. 
Tenia 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 unfrequently 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 thanin sheep, but unlike the Cen- 
urus, or “ water-brain,” these tumors are not confined to the 
lower animals. Theyare also found in the human body, and 
give rise to incurable and most horrible diseases, to which per- 
sons of all classes are liable,no 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 
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