Skin tests were made with Type I S.S.S. in 53 cases of Type I pneumococcus lobar pneumonia, 48 of which were treated with antipneumococcus Type I serum. In all but 1 of the 46 recovered cases a positive, immediate skin reaction was obtained at about the time of recovery. In 7 fatal cases reactions were consistently negative, even in the presence of circulating type-specific antibodies.
The skin test has proved to be an extremely valuable guide to serum therapy, and a definite prognostic aid. The test has distinct advantages over the agglutination reaction in that it is not merely an index of circulating antibodies. When positive, it invariably denotes that recovery has begun; when negative, it indicates further serum therapy. The mechanism of the positive skin test is closely related to that operative in recovery from pneumonia, and is apparently the resultant of antibody and tissue activity.