English: Engraving is of a scientist sitting at a table with a taxidermied bird in front of him as he catalogs bird specimens in the Natural History Laboratory of the Smithsonian Institution Building or "Castle," from an 1857 guidebooks Assistant Secretary Spencer Fullerton Baird unpacks his office and begins his career as Assistant Secretary of the Smithsonian Institution. In the Annual Report for 1850, he sets forth a museum program to Smithsonian Secretary Joseph Henry. Acknowledging Henry's stated policy of gathering only materials not previously collected by others, Baird proposes concentrating on collections illustrating the natural history of North America. He supports a system of exchanges using duplicate specimens and proposes to furnish travelers the means of "determining the character of objects collected in various part of North America." Baird sees the Smithsonian as the custodian of all objects of natural history belonging or to belong to the United States.