The simultaneous occurrence of bilateral pleural effusions is rare except in cardiorenal disease and as a direct complication of bilateral artificial pneumothorax used in the treatment of pulmonary tuberculosis. In comparison there is a relatively high incidence of unilateral tuberculous effusions occurring spontaneously or in connection with artificial pneumothorax, as shown in a study of 700 cases studied at the Department for Diseases of the Chest of the Jefferson Hospital and of an additional series from one service of the White Haven Sanatorium. According to the past histories there had been 108 pleural effusions and following entry 151.
Concerning the group of effusions observed during hospitalization, ninety-two were definite complications of artificial pneumothorax, of which fourteen cases were bilateral, the fluid having developed somewhat in relation to the progression of the pneumothoraces; in three cases of bilateral pneumothorax the fluid was limited entirely to one pleural cavity. Five patients with