350 



THE DOG IN DISEASE. 



etc., become the larval form referred to above ; and so the 

 biological circle is completed. 



Again, it is believed that the dog-louse {Trichodectes 

 canis), more frequently^ perhaps, the flea {Pulex canis), 

 swallows the minute eggs of segments of the tape- worm ex- 

 pelled from the dog and adherent to his hair 

 and proves the intermediate host, while these 

 parasites are again accidentally swallowed by 

 the dog ; hence the vicious circle. 



It is thus apparent that one dog with tape- 

 worm may infect a whole kennel of dogs. 

 All sorts of worms in the intestinal tract live 

 on the digestive food by which they are sur- 

 rounded. They may injure an animal, when 

 numerous, by taking up the nourishment be- 

 longing to it ; and by irritation, which has 

 innumerable reflex effects that express them 

 selves through every system of the body. 

 As it is most important to beware of these 

 symptoms, we instance some of them : 



Digestive. — Colic, diarrhoea, constipa- 

 tion, vomiting, slimy stools of a peculiar 

 wormy smell — it may be gray or blood- 

 stained — capricious appetite or loss of appetite, bloat- 

 ing, etc. 



Circulatory. — Blood impoverished, shown by pale 



Fig. 36.— TiENiA 

 echinococcus 

 (after Bris- 



TO we). 



a, Taenia magni- 

 fied 10 diame- 

 ters ; h, ovum 

 magnified 250 

 diameters. 



gums, etc. 



Cutaneous. — Harsh coat, skin eruptions, falling of hair. 



Respiratory. — Dry, hot nose, cough. A special form 

 of bronchitis may be caused by small worms in the bron- 

 chial tubes. 



