Atelectasis of the new-born has received scant attention in recent years, despite important advances which have been made in closely related fields. In current textbooks of pathology and of pediatrics, the subject is usually treated briefly, and its presentation is based on traditional conceptions. Certain interesting and highly skilful researches by earlier investigators have been forgotten by later writers. That the term atelectasis of the new-born has been loosely used and its significance misunderstood is shown by the frequency with which atelectasis has been regarded as a complete and satisfactory cause of death, not only in mortality records, but also in autopsy protocols. Clinical and pathologic observations on more than five hundred premature and full-term babies, as well as experimental studies made in the past few years, have led us to a reconsideration of the problem of atelectasis of the new-born. We shall particularly consider the following points:
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