In trying to decide what type of address I should deliver this evening, I attempted to place myself in the position of a member of this audience knowing even less than I about exoerythrocytic stages of malaria parasites, and imagine the questions about this subject likely to come to his mind. While in this position I seemed to hear questions propounded by all around me; which I noted and arranged in some kind of order, and decided to attempt their answer tonight to the best of my ability. Inasmuch as these cover a wide scope, I must warn you that my answers will necessarily be brief. Fairly comprehensive reviews of most of the phases covered have already been published (4, 5, 6, 8, 14, 15, 18).

What are exoerythrocytic stages? This is, perhaps, the easiest of the questions to be answered. As the name indicates they are stages found outside of erythrocytes.