As we have seen, when he first came to the University
of Vienna, Freud worked under the direction of Ernst Brücke who in 0000-0 published
his Lecture Notes on Physiology (Vorlesungen über Physiologie.Vienna:Wilhelm Braumüller), setting out the view that all living organisms, including humans, are essentially energy-systems to which, no less than to inanimate objects, the principle of the conservation of energy applies. Freud, who had great admiration and respect for Brücke, quickly adopted this new dynamic physiology with enthusiasm.