Studies in the aetiology of pulmonary tuberculosis

Summary (1) By measurement of the layer of skin and surface fat visible on miniature x-ray films, it is shown that radiologically normal male people destined to develop phthisis at a later date are already thinner than comparable controls, also normal but not destined to develop phthisis. A possible explanation of this was that our P.D.N. material included a preponderance of persons of a certain body type, characteristics of which were leanness and susceptibility to tuberculosis. The existence of such a type has been suspected since the time of Hippocrates but never actually proved. (2) By comparisons with controls it was shown that tuberculous and phthisis destined males tend to have relatively long narrow chests and hearts. Nevertheless this was not found to account for the greater leanness of P.D.N. males compared with controls. Possible causes of the association between leanness and predisposition to tuberculosis are discussed.