During the past two years several articles have appeared dealing with the opsonic index in the gonorrhea of adults and with the effect of therapeutic inoculation in this disease. The gonorrheal vulvovaginitis of little girls seemed to offer an interesting field for research of this kind and one as yet unexplored. Accordingly, during the summer of 1907, we undertook to examine children suffering from acute and chronic gonorrheal vulvo-vaginitis with reference to their opsonic index to the gonococcus; and later we took up the question of the influence exerted upon the index and upon the course of the disease by the injection of killed gonococci. As a result of these investigations we feel justified in making the following statements: 1. The opsonic index to the gonococcus is usually below normal in the chronic gonorrheal vaginitis of little girls and in acute vaginitis during the first weeks. 2. The index usually rises toward the end in cases which are recovering and remains more or less persistently low in cases which do not improve or improve very slowly. 3. It is sometimes possible to raise the opsonic index to the gonococcus by injections of dead gonococci, and when this occurs an improvement in the clinical condition usually occurs also. 4. The acute cases inoculated with killed gonococci from strains which had been grown for several months on artificial media improved rather more rapidly than did control cases who received no injections of killed gonococci. 5. Better results are obtained by the use of strains which have been grown for a long period on artificial media than by the use of freshly isolated strains, and there appears to be no advantage in using the patient's own organism.