A REQUEST was received in 1950 for blood sera of infants and children as a part of a national survey concerning the incidence of toxoplasmosis being conducted by Feldman. As a consequence, 47 blood samples were obtained from infants and children in the clinics and wards of the Charity Hospital of Louisiana. These specimens were collected on a single day, and the patients were selected only in that they were not suspected of having toxoplasmosis. The results of the methylene-blue dye test performed on the sera by Dr. Feldman1 were most startling in that the sera of 25% of the children in the age range of 0 to 19 years showed positive titers and that, further, in the 5- to 9-year age group 43% of the children tested had positive titers.2 It was further significant that most of these children had titers of 1: 16 or higher, suggesting