“…More recently, experiments have examined the changes in the concentration of paramagnetic metal ions (Swartz et al, 1973;Dodd, 1975;Dodd & Silcock, 1976) and a particular free radical, the ascorbyl radical (Dodd, 1973;Dodd & GironConland, 1975;Giron-Conland, 1975;Silcock & Dodd, 1976) during the development of experimental malignancies in mice and rats. This paper reports ESR studies on a murine myeloid leukaemia carried in RFM/Un Inice, and compares the results with those obtained in RF/J mice.…”