ATEIvECTASIS, COI.I.APSE OF I.UNG. 



Atelectasis in bronchitis, congenital, etc. Airless condition in the ab- 

 sence of exudation. Causes, congenital persistence in butcher animals. 

 Blocking of air tubes by exudate — ball valve. Desquamation of ciliated 

 epithelium. Compression by hydrothorax, pneumothorax, and false mem- 

 brane. Symptoms. Percussion flatness, juvenile respiration elsewhere, 

 blowing sounds loud. Drum like sounds on emphysema and pneumothorax. 

 Cyanosis. Lesions, depressed, flesh-like, non-crepitatiug lobules or lobu- 

 letes, sink in water, dilatable. Treatment, rouse respiratory centres, douches, 

 cold and warm, slapping, electricity, forced inspiration, diet, massage. 

 Treat attendant disease. 



This has been already referred to as a result of bronchitis, but 

 it deserves special mention as a sequel of that affection, and in va- 

 rious domestic animals, as an independent condition. The condi- 

 tion is one of consolidation of lung by the complete exclusion of 

 air, but without any infiltration of its substance by inflammatory 

 exudate or dropsical effusion. The tissue remains in its normal 

 state apart from the fact that its bronchioles and air sacs are undi- 

 lated. The affected portion has a solid dark fleshy appearance. 

 The collapsed portion often represents one lobule or group of lo- 

 bules which communicate with a single bronchium. 



Causes. In some instances the conditions remain from birth, 

 the lobule never having been called into use. This is seen espec- 

 ially in cattle and other meat producing animals, in which active 

 breathing is systematically suppressed in the interests of rapid 

 growth and the deposition of fat. In the improved breeds the 

 lungs remain larger than the exigencies of the life demand, and 

 large portions remain out of use. In bronchitis the condition is 

 acquired, and is mainly dependent on the blocking of a bronchial 

 tube with tenacious mucus or a dessicated mass. The pathologi- 

 cal lesions of bronchitis favor this since one of the earliest changes 

 in the inflamed mucosa is the desquamation of the columnar 

 epithelium. This removal of much of the cilia and the paralysis 

 of much of what is left annihilates for a time the normal method 

 of clearing away the secretion, and this being now produced in 

 excess blocks the tubes. This secretion virtually acts like a ball 

 valve in favoring the exit of the air during the convulsive expira- 

 206 



