Abstract
Summary 1. In evaluating any chemotherapeutic procedure, information must be obtained concerning the absorption, storage in the various organs and tissues, destruction within the organism, and route and rate of excretion of the particular drug under consideration in order to ascertain not only its therapeutic effect but also its possible toxicity. 2. Since the malaria parasite, in its asexual cycle, develops and reproduces within the blood stream, it is natural to presume that any effect which an antimalarial drug exercises on the parasite depends upon the concentration of that drug in the blood stream primarily. 3. Earlier methods for the determination of atabrine in the blood are considered and their limitations and inaccuracies discussed. 4. A new method is presented for the determination of atabrine, depending upon the simultaneous precipitation of blood proteins and extraction of the drug, its recovery in a pure state, precipitation, and final nephelometric estimation.