POSTKARTE Osborn, Henry Fairfield Author: Osborn, Henry Fairfield Recipient: Haeckel, Ernst Dating: ??.??.1906
BRIEF [O.A.] Janes, Lewis G... Author: Janes, Lewis G... Recipient: Haeckel, Ernst Corporation: The Brooklyn Ethical Association Dating: 14.11.1890
BRIEF OHNE UMSCHLAG Adler, M... M... Author: Adler, M... M... Recipient: Haeckel, Ernst Dating: 12.04.1909
BRIEF OHNE UMSCHLAG Adler, Felix Author: Adler, Felix Recipient: Haeckel, Ernst Corporation: Cornell University Dating: 19.11.1875
BRIEF [O.A.] Spencler, Otto Author: Spencler, Otto Recipient: Haeckel, Ernst Corporation: The Argus Pressclipping Bureau Dating: 13.08.1910
BRIEF OHNE UMSCHLAG Scheffauer, Herman Author: Scheffauer, Herman Recipient: Haeckel, Ernst Corporation: University Settlement Dating: 13.08.1909
BRIEF OHNE UMSCHLAG Scheffauer, Herman Author: Scheffauer, Herman Recipient: Haeckel, Ernst Corporation: University Settlement Dating: 12.09.1909
BRIEF OHNE UMSCHLAG Scheffauer, Herman Author: Scheffauer, Herman Recipient: Haeckel, Ernst Corporation: University Settlement New York Dating: 28.10.1909
BRIEF OHNE UMSCHLAG Scheffauer, Herman Author: Scheffauer, Herman Recipient: Haeckel, Ernst Corporation: University Settlement New York Dating: 01.04.1910