Since the first description of bronchiectasis by Laennec in 1819 its pathogenesis has been a controversial topic, and although the many theories have their recurring moments of popularity, none has as yet found general acceptance. One reason for this lies in the widely varying views of different workers as to the essential nature of the disease. Nowadays the divergence of opinion seems to be occupational, for, while many physicians and radiologists think of the bronchial inflammatory changes as mild and the dilatations of a mechanical nature, most surgeons and pathologists regard bronchiectasis as a destructive inflammatory process.

The pathology of bronchiectasis has been investigated for over a century and the various accounts are conflicting. It has been stated that many tissue changes described in the earlier literature could be attributed to terminal infections and post-mortem autolysis, and that operation specimens show less severe lesions which are more consistent with clinical findings. However, in several recent accounts the pathological changes described have been quite as advanced as those found in postmortem material,'but such descriptions have been found unacceptable to many clinicians, who regard radiological findings as truer reflections of the underlying pathology. The popularacceptance of this view, with its effect on theories of pathogenesis, has stimulated the present investigation. It was thought that diversity in the described lesions of bronchiectasis might be explained by one or more of the following suppositions.(1) Histological sections may not have been selected (by different investigators) from comparable areas of lung tissue.(2) Variation of histology is due to the severity, extent, and duration of the illness.(3) Bronchiectasis is not a single pathological entity, but a group of differing conditions having bronchial dilatation as a common factor.-