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 (Trichodectcs 

 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 

 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. 



FIG. 36. TJENIA 

 ECHINOCOCCUS 

 (AFTER BRIS- 

 TOWE). 



a, Taenia magni- 

 fied 10 diame- 

 ters ; fc, ovum 

 magnified 250 

 diameters. 



