1. Characteristic cutaneous responses to the type-specific protein-free carbohydrates of both Type I and Type II pneumococci have been "produced" in cases of lobar pneumonia due to either of these types by the intravenous injection of concentrated bivalent (Types I and II) antipneumococcic sera (Felton).
2. A positive cutaneous response to the specific polysaccharide of Type II pneumococci has been passively transferred from human cases convalescing from this infection to a patient suffering from pneumonia due to this organism.
3. The cutaneous responses to the type-specific polysaccharides and circulating antibodies were studied in 51 cases of lobar pneumonia. Positive cutaneous reactions were, in most instances, associated with recovery, even when purulent complications were present. Failure to elicit a positive reaction was usually followed by a fatal outcome.
4. The positive reactions in patients who were treated with concentrated sera and recovered were most often elicited within 24 hours after the first dose and after a total of 40 cc. had been given.
5. The positive skin reactions obtained after the administration of specific antisera were associated with the presence of mouse protective antibodies and agglutinins in the sera of the patients.
6. The immune reactions in serum treated cases receiving repeated inoculations with the specific carbohydrates disappeared more rapidly than in similar cases receiving no antiserum. It is suggested that the administration of antisera in someway interferes with the production of antibodies by the intracutaneously injected carbohydrates.