BIOLOGICAL RHYTHMS AND CYCLES

Abstract

The author''s category, "Periods of less than 24 hrs.," includes variation of activity in human infants, rodents, and Actinia equina, irritability in Amblystoma punctatum, frequency of human births in relation to phase of the tide. "Diurnal periods" embrace activity in invertebrates, fish, birds, and mammals, including man; color changes in invertebrates and fish; body temperature in birds and mammals, including man; and a miscellany: blood constituents, growth, heart rate, basal metabolic rate, minute volume of the heart, urinary excretion, cutaneous sensitivity, incidence of epileptic fits and of the onset of labor. "Periods of more than 24 hrs." include sexual cycles, human and otherwise, feeding in bedbugs, sleep characteristics in psychotic patients, human body temp., heart rate, blood pH, certain diseases, moods and emotions, and others, some based on laboratory data, some on vital statistics, and meteorological or astronomical tables. The physiological mechanisms underlying periodicity are discussed in a general way.