The presence OF disseminated miliary lesions in the lungs, demonstrable on the chest roentgenogram, is of frequent occurrence and is seen in a wide variety of diseases. More than 80 conditions capable of producing this appearance have been recorded (1–3). Such a long list of possibilities makes it extremely difficult to establish a clinical diagnosis in a given case, and any lead obtainable from the roentgenogram is of considerable help. For instance, roentgen evidence of associated enlargement of the hilar and mediastinal nodes, pleural involvement, or cardiac abnormality may suggest one or another etiology. Some writers have considered differences in sharpness, configuration, size, number, and distribution of the individual miliary nodules helpful in differential diagnosis. An approach which has proved particularly useful in this institution, but which has not been emphasized in the literature, is the observation of change in the roentgen findings—specifically, the rate of progression or regression of t...