Hermann Biow; The infusorian Christian Gottfried Ehrenberg; donation Hermann Stachow; daguerreotype; image size (clear measure): height: 21.5 cm; width: 16.1 cm; silver mark: recto o. li. on plate: asterisk; hallmark: recto o. r. on the plate: 30; numbered: verso o. r.: in black ink on label: D.S. 83; portrait photography; man; historical person; seated figure; half-figure portrait; scholar; philosopher; (applied) natural sciences; biology