The exhibit, “Dark Fields of the Republic: Alexander Gardner Photographs 1859-1862,” now at the National Portrait Gallery inspired choreographer Dana Tai Soon Burgess to create “The Foster Suite: The Remains of Loss and Longing,” which his Dana Tai Soon Burgess Dance Company presented in the Gallery’s Kogod Courtyard in two performances Feb. 28. The site served as infirmary during the Civil War where Clara Barton and Walt Whitman attended to the war wounded. At a post-performance reception at NoPa restaurant and bar, Burgess offered a toast to dance. His company will embark on two international tours as a State Department cultural envoy.