BRIEF [O.A.] Moleschott, Jacob Author: Moleschott, Jacob Recipient: Haeckel, Ernst Dating: 02.01.1886
BRIEF [O.A.] Preyer, William Thierry Author: Preyer, William Thierry Recipient: Haeckel, Ernst Dating: 14.04.1886
BRIEF [O.A.] Semon, Richard W... Author: Semon, Richard W... Recipient: Haeckel, Ernst Dating: 15.03.1886
BRIEF [O.A.] Semon, Richard W... Author: Semon, Richard W... Recipient: Haeckel, Ernst Dating: 29.08.1886
BRIEF [O.A.] Betha, Antonio de Author: Betha, Antonio de Recipient: Haeckel, Ernst Corporation: Circolo Letterario Giovanile Dating: 03.09.1886
BRIEF [O.A.] Krauseneck, Heinrich Author: Krauseneck, Heinrich Recipient: Haeckel, Ernst Dating: 06.04.1886