BRIEF OHNE UMSCHLAG Altschul, Theodor Author: Altschul, Theodor Recipient: Haeckel, Ernst Dating: 28.05.1901
BRIEF OHNE UMSCHLAG Schatt, Karl Oswald [?] Author: Schatt, Karl Oswald [?] Recipient: Haeckel, Ernst Dating: 05.03.1912
BRIEF OHNE UMSCHLAG Bothe, Margarete Author: Bothe, Margarete Recipient: Haeckel, Ernst Dating: 01.12.1915
BRIEF OHNE UMSCHLAG Pick, Klärchen Author: Pick, Klärchen Recipient: Haeckel, Ernst Dating: 07.03.1917
BRIEF OHNE UMSCHLAG Wetzler, Hans; Haar, Robert Author: Wetzler, Hans; Haar, Robert Recipient: Haeckel, Ernst Dating: 16.02.1912
BRIEF OHNE UMSCHLAG Stern, Maximilian L. Author: Stern, Maximilian L. Recipient: Haeckel, Ernst Dating: 16.05.1901
BRIEF OHNE UMSCHLAG Novak, Theodor Author: Novak, Theodor Recipient: Haeckel, Ernst Dating: 14.04.1901
BRIEF OHNE UMSCHLAG Sloboda, Milan Author: Sloboda, Milan Recipient: Haeckel, Ernst Dating: 23.03.1901
BRIEF OHNE UMSCHLAG Kühnel-Engelsberg, Rudolf Author: Kühnel-Engelsberg, Rudolf Recipient: Haeckel, Ernst Dating: 09.04.1900