ATEIvECTASIS. COLLAPSE OF LUNG. 



Atelectasis in bronchitis, coiigenital, etc. Airless condition in the absence 

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

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

 Compression by hydrothorax, pneumithorax, and false membrane. Symp- 

 toms. Percussion flatness, juvenile respiration elsevifhere, blowing sounds 

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

 Lesions, depressed, flesh-like, non crepitating lobules or lobuletes, sink in 

 water, dilatable. Treatment, rouse respiratory centres, douches, cold and 

 warm, slapping, electricity, forced inspiration, diet, massage. Treat at- 

 tendant 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 

 various domestic animals, as an independent condition. The con- 

 dition is one of consolidation of lung by the complete exclusion 

 of air, but without any infiltration of its substance by inflamma- 

 tory exudate or dropsical effusion. The tissue remains in its 

 normal state apart from the fact that its bronchioles and air sacs 

 are undilated. The affected portion has a solid dark fleshy ap- 

 pearance. The collapsed portion often represents one lobule or 

 group of lobules 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 espe- 

 cially 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 



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