David Cappen Clapp (1806-1893), born in Massachusetts, began apprenticing at the age of 16 at the printing office of John Cotton, Jr. He eventually became sole manager of the office in 1831, entered a partnership with John Cotton, Sr., and changed the firm name to D. Clapp Jr. & Co. Clapp took over the business once more in 1834 and thirty years later his oldest son, John Cotton Clapp, joined the partnership, which became David Clapp and Son. Of notoriety in his printing business was the publication of the first weekly medical periodical in the United States, and Clapp had the distinction of being its proprietor and publisher for about fifty years.
Additionally, Clapp served in the 44th Massachusetts Volunteer Militia, April to August 1864. He then served as Second Lieutenant of the 8th Regiment of U.S. Colored Troops, which was organized between September 1863 and January 1864 at Camp William Penn, near Philadelphia, and was mustered out in November 1865, after doing duty in Texas as part of the force trying to convince France to pull its troops out of Mexico.
Sources : David C. Clapp Papers, 1856-1915, Dolph Briscoe Center for American History, University of Texas at Austin.
Acton Memorial Library Civil War Archives. Forty-Fourth Regiment Massachusetts Volunteer Militia (Infantry) Nine Months. Acton Memorial Library. http://www.actonmemoriallibrary.org/civilwar/Regiments/Mass/44MVI.htm (accessed June 17, 2010).
Battle of Olustee or Ocean Pond--Florida. Eighth United States Colored Troops. Florida Department of Environmental Protection--Recreation and Parks, Olustee Battlefield Historic State Park Citizens Support Organization, University of Florida--Thomas R. Fasulo. http://battleofolustee.org/8th_usct.html (accessed June 17, 2010).
From the guide to the Clapp, David C. Papers 66-28., 1856-1915, (Dolph Briscoe Center for American History, The University of Texas at Austin)