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many, especially when its gluttonous habits lead it 

 to feed on excrement. One of these parasites is the 

 worm, I have mentioned. 



"It is the most curious creature one could pos- 

 sibly imagine. Picture to yourselves a little bladder 

 full of liquid as clear as water; on this bladder a 

 very short and wrinkled neck ; finally, at the extrem- 

 ity of this neck a round head bearing on the sides 

 four suckers and at the end thirty-two hooks ar- 

 ranged in the shape of a crown in a double ring. 

 That is the worm, the hydatid. Each one is enclosed 

 in a sort of little pouch, a firm and semi-transparent 

 cell which derives its substance from the flesh of the 

 pig itself. Commonly the tiny creature is entirely 

 hidden in its snug retreat; at other times, through 

 an opening in the pouch, it stretches its neck and 

 pushes its head out a little, doubtless to feed on the 

 adjacent fluid matter by means of its four suckers. 

 As to the little bladder forming the other part of 

 the worm, it never leaves its cell, the cavity of which 

 it fills exactly. Hence the animal never changes its 

 place." 



"That must be a very dull sort of life," was Em- 

 ile's comment. "No exercise for the little worm ex- 

 cept occasionally sticking its head out of the bag 

 that holds it, and then drawing it in again and shut- 

 ting the door. Is this bag very large!" 



"There are different-sized ones, according to the 

 worm's degree of development, for as it grows its 

 dwelling also becomes larger. The usual shape of 

 these cells is that of a small egg, the greatest dimen- 



