Occlusive lesions in the pulmonary arteries of emphysematous lungs have been recognized for some time (Loeschcke, 1928; Karsner, 1933 Kountz and Alexander, 1934; Brenner, 1935; Christie, 1944; Gilmour and Evans, 1946). The changes described varied from an obliterative arteritis to patches of atheroma. Loeschcke referred to the loss of pulmonary capillaries as the cause of the pallor of emphysematous lungs, and contended thatKapillarschwund preceded the development of the lung lesions. Gilmourand Evans suggested that a weakness of the media of the pulmonary arteries had predisposed to endarteritis obliterans. This they had observed in a case of primary pulmonary hypertension. Brenner, however, believed that increasing degrees of arteriosclerosis in the lungs of patients over 40 occurred irrespective of pulmonary disease. Whereas lesions affecting the pulmonary arteries in pulmonaryemphysema have been studied, the pathology of the bronchial arteries in this disease is more obscure. In the course of investigations of the bronchial arteries in a variety of patho-logical lung conditions, it became evident to us that in cases coming to necropsy with a clinical diagnosis of pulmonary emphysema, and in others in which necropsy revealed bullous emphysema of the lungs, lesions in the bronchial arteries could be demonstrated. It is the purpose of this paper to describe these findings in the bronchial arteries, to correlate them, as far as possible, with other pathological and clinical features, and to assess their relevance in relation to this group of respiratory disorders.

The bronchial arteries were first observed by Galen (1562), and were defined as" vasa nutritiva" of the lungs by Reisseisen and von Sommering (1808). Thestudies of the normal anatomy of these vessels by Miller (1947) are of particular value. Several points from these anatomical studies are of importance for the discussion which is to follow,