Diseases of the Respiratory System 



181 



mucous membrane of the air-sacs and bronchi. When the 

 number of parasites is small they cause no serious inconven- 

 ience to the bird. When there are a large number present 

 they may cause inflammation of the membrane and secretion 

 of mucus or they may seriously obstruct the air passages. 



Treatment. — Treatment of infested birds is probably use- 

 less. Feeding sulphur with the food or compelling the birds 

 to inhale the fumes of burning sulphur or burning tar or the 

 steam of boiling tar water has 

 been recommended. 



If a flock is infested with 

 this parasite it is best when 

 possible to start a new flock 

 with incubator chicks raised 

 on a new range and carefully 

 protected from infection from 

 the old flock. Or stock may 

 be purchased from an un- 

 infested flock. Birds with 

 this parasite should not be 

 bought or sold for breeding 



or laying purposes, as the Fig. 33. — CytodUes nudus. 

 flock into which they are in- 

 troduced will become infested 

 from them. Since this parasite cannot live long outside 

 the bird's body, the houses, runs, etc., do not remain in- 

 fested long after all the diseased birds have been removed. 



Prognosis. — A bird once infected is probably never free 

 from the parasite but may live a long time little harmed by 

 its presence. 



The 

 air-sac mite. Greatly enlarged. 

 (After Theobald.) 



