Letter from Cyrus Adler, Assistant Secretary, to Frank Baker, Superintendent of the National Zoo 2/21/1908, February 21, 1908, Smithsonian Archives - History Div, Letter from Cyrus Adler, Assistant Secretary, to Frank Baker, Superintendent, National Zoological Park, stating that Baker's request for certification of two whites only positions was being denied by the Secretary, Charles D. Walcott. Walcott recommended Baker submit two certification requests that didn't specify skin color..