[Claude Bernard (1813-1878)--remarks on his methodology].

Claude Bernard is the most distinguished French physiologist of the 19th century. He has not only performed a great number of scientific experiments. Moreover he has formulated a strictly reasoned methodology. It seems to be very useful to observe it even in temporary scientific work. Unprejudiced observations and experiments initially carried out only in thoughts are necessary premises for the formation of well supported working hypotheses. Only under these prerequisites practical experiments are justified as a decisive control. Claude Bernard emphasizes the idea that in spite of the rational principles of research the scientist is not immune to psychological dangers leading him to erroneous concepts as dogmatization of scientific statements, uncritical assumption of scientific fashions and last not least undue respect for personal authorities. The applicability of Claude Bernard's methodology is scrutinized and interpreted by three examples of the fate of scientific problems.