Callan, [H G] Correspondence between H G Callan and Haldane. Includes the following letters: <ul><li>Correspondence dated 1946 between H G Callan and Haldane regarding chiasmata in mosquitoes and newts. </li> <li>Letter from H G Callan to Helen Spurway dated 1949 regarding newt specimens for study.</li> <li>Four letters dated October 1949 - March 1950 from H G Callan and Haldane regarding a meeting of the Genetical Society and a joint paper between H G Callan and Helen Spurway. </li> <li>Two letters dated December 1950 between Haldane and Callan regarding the joint paper between Callan and Spurway. </li> <li>Copy of a letter dated November 1952 from Haldane to Callan regarding chiasmata.</li> <li>Copy of a letter dated December 1952 from Haldane to Callan forwarding a letter (no copy of the forwarded letter).</li> <li>Copy of a letter from Haldane to Callan regarding a statistical test for the lack of chiasmata near the centromere</li></ul> 1946-1957