Abstract
1. A simply made selective tellurite medium for the isolation of Corynebacterium diphtheriae and the identification of its types has been described.2. The ingredients of this medium are easily obtained and can be stored for any length of time making the medium readily available at short notice.3. Large or small quantities of the medium can be made with equal facility.4. When grown on the medium, C. diphtheriae will produce colonies characteristic of its type, be it gravis, mitis or intermediate.5. The appearance of the colonies has been described and has been shown to resemble closely, in the case of each type respectively, the appearances described by the Leeds workers (Anderson et al. (1931)) on their medium in the original papers.6. The possibilities of the use of this medium for diagnostic routine swab examinations have been briefly referred to.