A New Phenotype (McLeod) in the Kell Blood‐group System *

Mr. McLeod, the possessor of a new Kell phenotype, lacks antigenic determinants* K1 (Kell), K3 (Penney), and K5 (Peltz). He has variants of K2 (Cellano) and K4 (Rautenberg). This phenotype appears to establish K5 as distinct from K1, K2, K3, and K4. The notation used in this paper is one proposed for the purpose of testing the usefulness of a system of basically numerical symbols.