From August, 1913, to January, 1919, the Pirquet test was applied in the Babies' Hospital in 3,742 cases. It is the custom at the hospital to apply the test as a routine procedure in cases of acute and chronic illness, feeding cases, malnutrition, etc. It is not, as a rule, applied to children admitted for surgical operation for harelip, cleft palate, adenoids, tonsils, hernia, pyloric stenosis, etc. During the period covered in this study 7,494 children were admitted to the hospital. The test was applied in 3,742 cases, or in 49.9 per cent, of those admitted. The test was positive in 573 cases, or 15.3 per cent. Crude tuberculin, commonly known as Koch's O. T., furnished by the New York Department of Health, was used undiluted in every instance. The test was applied on the arm or leg. Two light scratches were made approximately ¼ inch in length and 2