Internal Parasites. 225 



sanguinolenta — the blood-red species— which usually occu- 

 pies small tumours in the mucous lining of the stomach. 



"The three-corner-headed strongle {Dockmiits trigono- 

 cephalus) infests the intestinal canal. The wrinkled thread- 

 worm (Trichosoma plica) gains access to the bladder. The 

 whip-worm of the dog [Tricocephalus depressiusculus) inhabits 

 the caecum. The spiral Resh vforra (Tric/iina spiralis) has 

 frequently been reared both in the intestines and muscles 

 by experiment. 



" The blood-infesting^thread-worm of Grube and Dela- 

 fond {Filaria kcematica) is probably a distinct species ; and 

 the same may possibly be said of Gescheidt's sma^l 

 nematode (Filaria trispinulosd), discovered in the eye. 

 There are also the small thread-worms {Filaria hepatica) 

 found by Mr. T. Mather, V.S., in the liver-ducts and 

 substance of the gland, as well as in cysts within the walls 

 of the intestines. 



" Lastly, there is another canine haematozoon, the males, 

 females, and embryos of which, according to Professor 

 Leisering, occur in the venous blood of certain parts of the 

 body of the dog {Hcematozoon subulatum)." 



Another, one of the most difficult to eradicate, and 

 perhaps, as Youatt observes, " the most injurious of the 

 intestinal worms," is the tmnia, or tapeworm. With regard 

 to this species. Dr. Cobbold remarks : " Although the lum- 

 bricoid worms of the dog constitute an important section 

 of the canine parasites, the practical interest attaching to 

 them is scarcely so great as that which appertains to the 

 tapeworms. If, on the one hand, it be allowed that the 

 canine cestodes are not so numerous as the nematodes, it 

 must, on the other hand, be admitted that (as regards 

 public health,* and the propagation of parasitic diseases 



* In the first report of the medical officer of the Privy Counc 1, Mr 



Gamgee observes : '' There is no doubt that eggs of the tapeworm, Ae- 



veloped trom Cysizceuus ieftuicolh's in the intestines of the dog, will 



produce the hydatid in the mesentery and liver of human beings, as it 



Q 



