Effects of preterm delivery on the timing and rate of switch-over from fetal to adult erythropoiesis; direct determination by estimation of HbF and HbA in reticulocytes : B.M. Holland, H.M. Phillips, J.G. Jones, A.L.M. Abdel-Moiz and C.A.J. Wardrop, Paediatric Department, Queen Mother's Hospital, Glasgow, Haematology Department, University of Wales College of Medicine and Biochemistry Department, University College, Cardiff, U.K. (Introduced by J.K. Stothers)