Studies on the Chemotherapy of the Human Malarias

The relative effectiveness of the various cinchona alkaloids in the treatment of malaria has been the subject of numerous investigations since the meeting of the Madras Commission in 1868 (1). Without exception, studies undertaken prior to the recent war involved the appraisal of the comparative antimalarial activities of quinine, quinidine, cinchonine and cinchonidine on the basis of the oral dosage administered during one or another standard therapeutic regimen. Although the conclusions derived from these studies are not in complete agreement, it has been the general impression that all four of the cinchona alkaloids possess roughly equivalent antimalarial activities. Therefore, it is surprising that quinine alone has come into general use in the suppression and treatment of malaria. The need for a further appraisal of the other cinchona alkaloids arose early in the course of the war because of the shortage of effective antimalarial drugs. Various cinchona barks containing the principal crystallizable alka-