Ludwik Fleck, Edmund Husserl : on the historicity of scientific knowledge -- Gaston Bachelard : the concept of "phenomenotechnique" -- Georges Canguilhem : epistemological history -- Pisum : Carl Correns's experiments on Xenia, 1896-99 -- Eudorina : Max Hartmann's experiments on biological regulation in protozoa, 1914-21 -- Ephestia : Alfred Kähn's experimental design for a developmental physiological -- Genetics, 1924-45 -- Tobacco mosaic virus : virus research at the Kaiser Wilhelm Institutes for Biochemistry and Biology, 1937-45 -- The concept of (...) the gene : molecular biological perspectives -- The liquid scintillation counter : traces of radioactivity -- The concept of information : the writings of François Jacob -- Intersections -- Preparations -- The economy of the scribble. (shrink)