Morphologic Changes in Pulmonary Emphysema.

I NTENSE INTEREST EXPRESSED BY CLINIcians, physiologists, and pathologists in pulmonary emphysema has stimulated the need for establishing some criteria for the normal anatomy and subsequent pathologic change. Regardless of the conflict in the theories of etiology, we must be cognizant of certain changes which take place in the pulmonary parenchyma. The fine relationships between structure, function, and the effects of the disease process previously have been difficult to study. Routine histologic studies on conventional 5p sections of lung provided earlier morphologists with considerable information regarding certain structural changes. Newer techniques developed in recent years now provide a means for obtaining additional pathologic information which was beyond the capabilities of previous methods.'" One may now survey overall changes in the gnws sections of the lung, as well as investigate additional histologic responses in the alveolar wall, vasculature, and corresponding airway structures. Documentation of these changes, combined with pre-