BRIEF OHNE UMSCHLAG Tille, Alexander Author: Tille, Alexander Recipient: Haeckel, Ernst Dating: 11.09.1895
BRIEF OHNE UMSCHLAG Tille, Alexander Author: Tille, Alexander Recipient: Haeckel, Ernst Dating: 31.12.1895
BRIEF OHNE UMSCHLAG Hoyle, William E. Author: Hoyle, William E. Recipient: Haeckel, Ernst Corporation: The Owens College Dating: 17.08.1895
BRIEF OHNE UMSCHLAG Spencer, Herbert Author: Spencer, Herbert Recipient: Haeckel, Ernst Dating: 02.11.1895