The role of secondary vectors of malaria in North-East Tanganyika

Abstract

The original stains of Romanowsky were aqueous solutions. Their superb quality at their best has perhaps remained unrivalled. Their defect lay in their capricious behaviour, mainly from variations in the azures and in the pH of the solutions. Their displacement by the methanolic stains of Leishman, Giemsa, and others, testifies to the weight of these objections. These particular criticisms of aqueous Romanowsky stains are no longer valid: azures are usually reliable; pH is controllable. Simple and stable aqueous solutions which meet most and perhaps all the routine demands of Romanowsky staining for malaria diagnosis are technically feasible. How wide is the field for their use? To what extent do their manifest advantages in speed, simplicity, stability, and economy, weigh in their favour? These questions are implicit in this paper and in the technical trivialia—variations on the original Romanowsky theme—it records. The answers are for others, especially for the thousands of workers in the outposts by whom the diagnosed malaria of the world is mainly seen.