CHAPTliR II, 



Diseases of the Organs of Respiration. 



STRrCTVRE AND FUNCTION — SIMPLE CATARRH — ROUP, CONTA- 

 GIOUS CATARRH — BRONCHITIS — THE GAPES, VERMINOUS 

 TRACHEO-BRONCHITIS, SYNGAMOSIS — CONGESTION OK 

 THE LUNGS, PULMONARY CONGESTION — PNEUMONIA — 

 MYCOSIS OF THE AIR-PASSAGES, ASPERGILLOSIS — THE AIR 

 SAC MITE. 



STRUCTURE AND FUNCTION. 



i^^^^HE respiratory organs of birds differ consider - 

 / \ abh' from those with which we are familiar in 

 ^^i^ the Other species of domesticated animals. 

 The plan of structure of these organs follows 

 more closelj'' the analogous organs of reptiles than it 

 does those of mammals. This should not excite sur- 

 prise as it is now admitted that birds are descended 

 from some animal of the reptilian group. 



The lungs are confined, as they are in the tortoise, 

 to the back part of the body cavit}', and are firmly 

 attached to the ribs and the spaces between these bones. 

 Large membranous sacs, communicating with the lungs 

 and serving as reservoirs of air, extend to the posterior 

 portion of the abdomen and even into the bones. The 

 lungs are not suspended freely and divided into lobes 

 as we see them in other farm animals, but the}' are 

 attached to the back part of the chest and are accu- 



