There are a number of disorders which recur with remarkably regular periodicity over many years without affecting the general health otherwise. In different persons the episodes are characterized by different features, which allow an arrangement of the disorders accordingly into four groups as periodic fever, periodic abdominalgia (benign paroxysmal peritonitis), periodic (cyclic) neutropenia and periodic (intermittent) arthralgia.1The name periodic disease was proposed to embrance the conditions in a newly established symptomcomplex, but it appears that periodicity of disease was known to the ancients and was ascribed to the influence of solar and lunar cycles.2Knowledge of its cause has not progressed much further. Infectious, allergic, endocrinologic, epileptic or migrainous influences have been held responsible; however, as Mead3wrote apropos of the subject in 1704, "and thus far the foundation was good, but when a false theory happened to be joined to true observation, this did considerably