THE PRESENT STUDY is part of an investigative project designed to classify pulmonary emphysema in the human being. One phase of the study called for an animal to be used experimentally in an effort to produce emphysema. It appeared logical to select an animal possessing a lung anatomically similar to that of man. A review of the literature revealed surprisingly little detailed information on the subject.
For many years, however, certain species differences in lungs have been recognized.1, 2 Degree of lobation and lobulation has been noted to be widely variable.3,4 A distinction has been made between animals with thick pleurae and thin pleurae.5 It has been shown that the rabbit does not possess respiratory bronchioles, but that many other animals do.6 Differences in the distribution of the bronchial artery have been reported,5 but the extent of distribution of the vessel has been the