6i6 THE BOOK OF -JJIH Doc. 



ducing death from disintegration of that organ. It is called the giant strangle (Estrangylus 

 gigas). It is shaped like the common round-worm, and in some animals, for instance the 

 North American mink, this terrible parasite has, according to Cobbold, been found to exceed a 

 yard in length, and equal one's little finger in thickness. 



There is a round-worm which at times infests the dog's bladder, and may cause occlusion 

 of the urethra ; a whip-worm inhabiting the caecum, another may occupy a position in the mucous 

 membrane of the stomach, some infest the blood, and others the eye. 



2. Teenies or Tape-worms. 



Probably one of the commonest of cestodes or tape-worms, and one with which many of my 

 readers are doubtless only too familiar, is the cucumerine (Toenia cucumerinus). 



This is a tape-worm of about fifteen inches in average length, although we have taken them 

 from Newfoundland pups fully thirty inches in length. It is a semi-transparent entozoon, each 

 segment is long compared to its breadth, and narrowed at both ends. Each joint has, when 

 detached, an independent existence. 



And here is a curious and noteworthy circumstance with regard to the propagation of 

 tape-worms. These animals live for one portion of their existence, and in one state, in one 

 animal, and for another in another. Indirectly, tape-worms are generated from eggs ; that is the 

 fully-developed tape-worm lays a number of eggs, each of which may contain one or many 

 embryo entozoons ; but this egg must first be swallowed by an intermediary bearer by some 

 small animal where it is hatched, and where the embryos live as guests until their host happens 

 to be swallowed by a larger animal, and in the body of this latter it is developed into the 

 mature or complete tape-worm. 



To give an example. A dog is infested with the common cucumerine we have just 

 described ; well, a segment or two escapes ab ano whilst the dog is lying among his straw. 

 As this segment has a semi-independent existence it manages to crawl away up through and 

 over the dog's coat, and as it moves it deposits or drops its eggs. Now, if this dog is not 

 only infested with tape-worm but also with the Trichodcctes latus, or common tlog louse, 

 probably some of these disgusting parasites will play the part of intermediary bearer or host 

 to the embryo tape-worms, for they swallow the eggs which the entozoon has dropped, and 

 in the body of the trichodectes the eggs are hatched, and little six-hooked embryo cucu- 

 merines are the result. 



The dog louse, infested with the larvae, may drop into the water dish, and thus be 

 swallowed by other dogs ; or it may be introduced into their bodies in several other ways 

 we need not specify. But, getting there, it soon becomes developed into the perfect tape-worm. 



We see, then, that without this intermediary bearer, the internal parasite the tapeworm 

 would not be reproduced. This surely teaches us to keep our dogs' coats and their kennels 

 clean, if we would save the poor animals much unnecessary suffering and pain. 



Every one has heard of the gid in sheep, known in different parts of the country as the 

 "sturdy," "vertigo," "staggers," "turnside," or the "whirls." Well, if the brain of an animal 

 that has died of this disease be opened, there will be found therein what are called hydatids 

 or cysts, little bladder-shaped objects. These are nothing more or less than small colonies of 

 the larvas of the very large tapeworm, called the Tcenia coenurus. We have seen this parasite 

 nearly two yards long, and repeatedly over one yard. Each gid hydatid is loaded, so to speak, 

 with hundreds of tapeworm heads, growing from a common centre, and every head, if intro- 

 duced into the dog's body, is capable of being developed into a tapeworm. 



