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3. Evidence for circadian rhythm of the mitotic activity of the adrenal medullary cells with a peak at noon, has been shown in rats byMalvaldi et al.1.
4. H. Haug, inMedizinische Grundlagenforschung (Ed. K. Fr. Bauer, Georg Thieme, Stuttgart 1962), vol. 4, p. 229.
5. E. M. McKay andL. L. McKay, J. exp. Med.43, 395 (1926).