A certain number of authors have already drawn attention to the association between interlobar pleurisy and massive pneumonia. Thiroloix and Rosenthal1 consider massive pneumonia to be the initial reaction of an interlobar pleurisy. Chauffard, and later his pupils, Guy, Laroche, Boidin and Huber, have showed the inadequacy of radioscopic examination in the diagnosis of certain interlobar pleurisies.2 More recently, Ardin-Delteil and Raynaud,3 Caussade and Deberdt4 have cited observations of interlobar pleurisy masked by massive pneumonia. This question has been the subject of a thesis by Pesle (Algiers, 1922). Finally, Ardin, Delteil, Derrien, Lévy and Valensi, from a review of the reported cases, have made the following conclusions:
That massive pneumonia may lead to an encysted pleurisy, and that one may consider it as a pulmonary reaction vis-à-vis a localized pleural inflammation.
That the diagnosis may be uncertain for a long time, even until the