Since the introduction of the erythrocyte sedimentation test into clinical practice numerous publications have dealt with its value in the diagnosis, prognosis and treatment of tuberculosis. The overwhelming majority of articles reflect the following convictions: 1. It is a reliable gage for the detection of active pulmonary tuberculosis. 2. The sedimentation rate of erythrocytes is directly proportionate to the extent of tuberculosis. 3. The test conforms rather snugly to the underlying pathologic process, being more rapid in association with the predominantly exudative type of lesion than in the case of productive or fibrosing tuberculosis. 4. An increased rate of erythrocyte sedimentation is of direct prognostic value and a sensitive signal of an oncoming spread of the disease. 5. In cases of pulmonary tuberculosis in which collapse therapy is instituted the test is a competent index of improvement which may not be detectable by other clinical means. For the purpose of