THE HYDATID OR BLOB. 



205 



valent to blood, and then distributes It throughout the 

 body/ 



Flukes are never found in the arteries of the liver, 

 as has been erroneously stated by some writers, their 

 abode being limited to the gall bladder and its ducts. 

 In these they are often present in such numbers as to 

 cause great distention of the sac and tubes, and in some 

 instances the irritation produced by them leads to the 

 thickening of the walls of the gall bladder, and to a 

 deposition of calcareous matter between its coats ; fre- 

 quently also to complete obliteration of portions of the 

 ducts. Hence the crackling sound sometimes per- 

 ceived when handling the liver of a rotten sheep. 



(163.) The Hydatid or Blob (Cysticercus tumi- 

 coUis, Fig. 1. Plate VII.) so frequently found in sheep, 

 is in form one of the simplest of the entozoa (literally 

 dwellers within), being little more than a bag contain- 

 ing a quantity of fluid. As relates to outline, this 



Jiydatid bears no small resemblance to a Florence flask. 



[t is said to have a head, h. — a neck, w. — a body, b. — 



ind a posterior or candal vesicle, c. v. Its claims to 



le title of an animal have been much disputed, but as 



it has been seen to move spontaneously, and as the 



mtained fluid is always essentially different from that 



[by which the hydatid is surrounded, the question may 

 )e looked upon as set at rest.f 



• The exctraination of fluke worms is much facilitated by placing 

 several of various sizes flat upon a slip of glass, and allowing them tt 

 dry in this position. On holding the glass between a bright light and 

 a lens, and looking through the latter, the distribution of the Tessels, 

 and the position and form of the eggs, are beautifully displayed. 



t The property of acting on organized matter, so as to convert it 

 into substances similar to those which constitute the agent, if charac- 

 teristic of a vital power. 



T 



