Jenner, Gjessing, Cox, Davies-Jones, Hullin, and Hanna (1967) have presented some biochemical and clinical studies of a patient who showed a remarkably precisely timed manic-depressive psychosis. For the last eleven years the patient has been alternately depressed and lethargic for 24 hours, then elated for 24 hours, and so on almost without fail. Harding, Jeavons, Jenner, Drummond, Sheridan and Howells (1966) published electroencephalographic studies showing the 48-hour rhythm in the patient's electroencephalogram. The harmonic mean, the mean abundance and variability of the alpha rhythm all showed a striking 48-hour cycle. A number of similar patients have been described and are conveniently listed by Menninger-Lerchenthal (1960), Richter (1960), and Bunney and Hartmann (1965). Jenner (1965) made some suggestions about possibly heuristically helpful electronic analogues which might appropriately represent some of the underlying mechanisms of the 48-hour syndromes.