Human hemoglobin H has been described in some detail by Rigas, Koler and Osgood.'Chemical investigations of chromatographically purifiedZ hemoglobin H, here presented, lead to a further understanding of its structure and of its relation to other human hemoglobins. When DNP-globin H was prepared and examined by methods previously described, s4s5 the result was approximately four N-terminal valyl residues per molecule ...