BEHAVIOUR AND MOOD CYCLES APPARENTLY RELATED TO PARATHYROID DEFICIENCY.

INCREASING interest in the cyclic behaviour of man and animals has been evidenced in recent years, especially in so far as these cyclic changes are related to glandular disturbances. In studies of the spontaneous activity of rats the following cycles have been observed: a 4-5-day cycle associated with ovulation (Wang, 1923) ; a 14-day cycle after section of the pituitary stalk (Richter, 1933) ; a 15-20-day cycle after parathyroidectomy (Richter and Eckert, 1937) ; a 25-35-day cycle after thyroidectomy (Richter, 1933) ; and a 100-day cycle after removal of one ovary and all except a small part of the other ovary (Richter, 1927). Hitherto, in other animals and in humans the only cycles definitely known to depend on endocrine glands were the ovulation and menstrual cycles. In humans with pathological disturbances we know of several other cycles, but we have no knowledge regarding their origin (1) the morning-evening variations in mood seen particularly in depressions (2) a 2-day cycle of alternating good and bad days of behaviour and sleep found in manic-depressive patients (Richter, 1938) ; (3) a 4-6-day cycle manifested in sleep (Richter, 1934) ; and (4) a 9-11-day cycle manifested in attacks of gastric pain (Levine and Richter, 1935). A cycle of approximately 40 days' duration associated with parathyroid deficiency has now been observed in a parathyroidectomized monkey, and a cycle of about the same length of time has been observed in a patient with a parathyroid deficiency.