The Derer´s biological - cosmic week and the Halberg´s circaseptan chronome.

There are three common periodic intervals in the life of each human being from time immemorial: the day, the week and the year. The first one is given by the Earth´s rotation, the latter one by its revolution around the Sun. These both do have clear biomedical counterparts. The 7-day week, basically linguistically "period of change" (or a similar period, e.g.10 days in Egypt or 8 days in Etrutria) was obviously originally considered mainly as a product of a societal agreement. Two groups of Czechoslovak clinicians-scientists, however, noted in forties of the XXth century an approximately week period in human laboratory data, after similar attempts abroad a few years earlier. In fifties, L.Dérer, respecting the mathematical and biological principles in medicine and supported by the mathematician A.Huťa, demonstrated the presence of the "6-day" rhythm in blood leukocyte counts in patients with leukemia, treated by cytostatics. Posing the question "Where is it from?", he considered also cosmic influences but was unable to study this issue more deeply due to his premature decease. Two decades later, the "Dérer´s circaseptans" found wide confirmation not only in human medicine but also in biology. The pioneering role here belongs to Franz Halberg, USA, the godfather of the "circadians" (originally "Halberg´s paranoia") since the fifties. The possible geocosmic roots of circaseptans are supposed in the geomagnetic activity from interplanetary space, generating under the influence of the Sun rotation the periods around 6-7 days. This is presently documented, surprisingly, also by analysing the Dérer´s original data using more advanced, inferentially statistical method - the Halberg cosinor regression. Thus, the optimal approximation has been achieved for the period of 6.75 days - the 4th harmonics of the Bartels solar rotation cycle. Accordingly, the week can be now, after Dérer and Halberg, understood also - same as day and year - as a biological - geocosmic phenomenon, a geomagnetic week, genetically acquired in the course of billions years´ of evolution, encoded in our chronome. The personality of Ladislav Dérer should, in the history of the Czech and Slovak biomedical sciences, be permanenly standing by such giants as the well known Jan Evangelista Purkyně ("Purkinje") or as Bohumil Němec, discoverer of the mechanism of positive geotropism of plant roots (Fig. 3, Ref. 28).