This study was undertaken with the hope of devising some method by which the abnormal shadows in the thorax of the newly-born could be differentiated from the normal ones. At the onset we appreciated that we had undertaken a problem of greater magnitude than we had expected. The deeper we went into the subject the greater was the variance in the shadows that we found could exist without causing any clinical symptoms. It was soon fully appreciated by us that it would require the study of a large series of cases before any attempt could be made to declare the normal to be such, and further we became more forcibly convinced that the normal shadows would first have to be determined before the abnormal could be recognized.
In presenting the observations of the study we do so in the form of a preliminary report.
Our study is based on observations