Physiology with cool obsession: Carl Ludwig--his time in Vienna and his contribution to isolated organ methodology.

This short report presents new information on Carl Ludwig's move from Zurich to the chair of physiology in Vienna and the 10 years he spent here and characterizes some of his contributions to experimentation methodology in working with isolated organs. Two up to now unknown documents concerning his call to the chair of physiology and zoology at the Josephs Academy, a military academy; have been found in the Public Record Offices in Vienna: a secret service report and the letter of Ludwig with his conditions for accepting the appointment. Some characteristic sections are cited. The time in Vienna between 1855 and 1865 is depicted against the background of political processes in Europe after the 1848 revolution. Ludwig's and his pupils' work with isolated organs is analysed briefly with some examples, especially relating to heart and kidney and a kymographion shown with a 20-channel registration module. The first "heart-lung machine" is discussed.