Christoph Wilhelm Hufeland (1762-1836) was one of the eminent physicians at the time of Goethe. When only 21 years old, he followed his father as a medical practitioner in Weimar. In 1793 he became Professor of Medicine at the University of Jena, from where he moved, in 1801, to Berlin as the physician in ordinary to king Friedrich Wilhelm III, council of state, and Professor at the leading hospital, the Charité. Hufeland pioneered in what today would be called public hygiene. Many of his lectures and publications were addressed to the educated laymen. In his most read book, the 'Makrobiotik', he emphasizes the importance of the 24-h periodicity as a basic unit of biological chronometry. In view of this, Hufeland has become a kind of 'patron saint' to modern chronobiologists.