Folder B.37.1: 'Bacterial variation', 1946-1950. Work in collaboration with D.E. Lea. Extensive MS. drafts, working papers and calculations by Coulson and by Lea, most dated 1947. Correspondence with D.E. Lea 1947, with detailed discussion of the progress of the work. Correspondence with J.B.S. Haldane 1948-49 regarding publication of the work after Lea's death. MS. accounts by Coulson of his work with Lea, 4 pp. MS. and 6 pp. typescript (not identical texts) given as part of a discussion at…