Pasteur described postoperative atelectasis or collapse of the lung as a condition of this organ characterized by "the total deflation (as opposed to lobular or patchy collapse) of a large area of lung tissue, of sudden onset—in the absence of any signs of obstruction of the air ways or of any known source of compression—due to failure of inspiratory power and attended by definite physical symptoms and signs."
Since then, and even long before Pasteur had again brought it up as an actuality, many papers have been written on this puzzling condition. None seems to have given a definite solution to the etiology and the mechanism of it. In this paper, we propose to give the results of our experimental work conducted on fifty-six dogs. A careful study of the clinical symptoms, the physiologic phenomena, the roentgen-ray observations on serial pictures and the pathologic and bacteriologic condition of our animals