Abstract
It has been confirmed that native and clinical dextrans are antigenic in man. Three weeks after injn. of 1 mg. of dextran precipitins and cutaneous wheal and erythema sensitivity developed. The presence in human sera of antibodies to the pneumococcal polysaccharides which cross react with dextrans in other species (rabbit and horse) appears to have little to do with the reaction of humans to dextran. Antibodies produced after immunization with dextran are specific for dextran. The persistence of antibodies to dextran has been shown.