D/SEASES OF THE RESPIRATORY ORGANS. loi 



pig. Only those of the sheep, once introduced into the system, 

 will maintain their place in the lungs for the whole lifetime of 

 the host, though no more young worms should be taken in. 

 That of the ox, etc., on the other hand, is more likely to be 

 expelled, and therefore often infests its host but for a limited 

 period. 



The Syngamtis of the bird has probably the same history out 

 of the body, but this has not been so carefully studied. 



Within the chest the Strongyli live in the small terminal air 

 passages in their young or embryo state, in the larger air tubes 

 when mature, and in cysts in the lung substance when laying 

 their eggs or when about to die, that the eggs may be set free 

 and hatched. In the air passages they give rise to bronchitis, 

 in the lungs to pneumonia and deposits resembling tubercles, 

 but distingushable under the microscope by the presence of the 

 elliptical eggs and the embryo worms. 



The Syngamus of birds inhabits the air passages, and gives 

 rise to bronchitis. 



In all cases the parasites are most fatal to the young. 

 Although old animals continue to harbour them they prove 

 much less destructive and are often unsuspected. 



SYMPTOMS IN CALVES AND FOALS. VERMINOUS BRONCHITIS. 



HOOSE. HUSK. 



These are essentially those of bronchitis, with the difference 

 that the whole herd is affected, and mucus coughed up contain- 

 ing worms either singly or rolled up in bundles. There is at 

 first only a slight rather husky cough repeated at irregular 

 intervals. There follows dry, staring coat, embarrassed breath- 

 ing, and advancing emaciation. Soon the cough becomes 

 frequent, paroxysmal, and suffocating, with expectoration of 

 mucus and worms. Or the cough is soft, loose, and wheezing, 

 and the patient is weak, hide-bound, with sunken eyes and pale, 

 thin, or puffy membranes, dropsical swellings beneath the jaws, 



