POSTKARTE Preyer, William Thierry Author: Preyer, William Thierry Recipient: Haeckel, Ernst Dating: 01.01.1896
POSTKARTE Müller-Brauel, Hans Author: Müller-Brauel, Hans Recipient: Haeckel, Ernst Dating: 26.03.1896
POSTKARTE Haeckel, Ernst Author: Haeckel, Ernst Recipient: Delle Grazie, Marie Eugenie Dating: 29.10.1896
POSTKARTE Breitenbach, Wilhelm Author: Breitenbach, Wilhelm Recipient: Haeckel, Ernst Dating: 15.10.1896