430 ATONIC DISEASES. 



every precaution, appearing in the kennelled hound or shooting- 

 dog, as well as the pampered house-pet and the haK-starved cur. 

 In old and constantly used kennels they are particularly rife, and 

 I believe that, in some way, their ora remain from year to year, 

 attached either to the walls or to the benches. All of the varieties 

 met with are propagated by ova, though some, as the Ascaris lum- 

 hricoidcs, are also viviparous, so that the destruction of the worms 

 actually existing at the time the vermifuge is given does not neces- 

 sarily imply the after clearance of the animal, who may be infested 

 with them as badly as before, from the hatching of the eggs left 

 behind. The natural history of these parasites is, however, very 

 imperfectly understood, in spite of the carefully recorded and ex- 

 tended labours of Rudolphi, Schmalz, Cloquet, Creplin, and our 

 own Owen ; indeed, as it is not till after the death of the animal 

 infested by them that they can be reached, it is only wonderful 

 that so much is known. Besides the intestinal worms, there are 

 also others met with in the dog, including the large kidney worm, 

 [Strong ylm gig as), which shall presently be described, and the 

 hydatid, which is in all probability the cause of turnside ; but, 

 though found in the dog's brain, its presence has not, I believe, 

 been clearly associated with that disease. I shall, therefore, first 

 describe the appearance of each kind of worm ; then the symptoms 

 of worms in general ; and, lastly, the best means for their expul- 

 sion. 



The Mato-Korm {Ascaris rermicnlaris) is much larger than its 

 representative in the human subject, which is a mere thread, and 

 is hence called the " thread- worm." In the dog it is about an 



