Dewey Jackson Short, 81, a former Republican representative in Congress from Missouri's 7th District and later an assistant secretary of the Army, died of a heart attack Monday at his home in Washington.

The "Ozark hillbilly," as he like to refer to himself, continued to maintain homes in Washington and his native Galena, Mo., after his retirement from government service in 1961.

Known for his silver-tongued oratory, Mr. Short, who at one time had been a Methodist minister and teacher of philosophy, continued to serve as a lecturer after retirement.

He was first elected in 1928 as a "boy congressman" shortly after serving as pastor of the Grace Methodist Church in Springfield, Mo. He served two years in Congress but failed in his bid for reelection.

Mr. Short was sent back to Congress by the voters in 1934, and held his seat until January 1957. The 7th District he represented included Missouri's section of the Ozark Mountains.

During his tenure Mr. Short became the ranking Republican on the House Armed Services Committee and served as its chairman in 1953-54, when the Republicans had control of Congress.

On military matters, Mr. Short generally believed in strong military forces and he backed Pentagon programs to bolster national defense. He was strongly opposed, however, to universal military training.

After he lost another reelection bid in 1956, he was named assistant Army secretary for civil-military affairs. As such, he was chairman of the board that directed operations of the Panama Canal. He also was responsible for the rivers and harbors and flood control work of the Army Engineers and was the military contact with Civil Defense.

Mr. Short grew up in Galena. After serving with the U.S. Army in World War I, he graduated from Baker University in Baldwin City, Kan. He also graduated from Boston University in Massachusetts.

He took further studies at Harvard University, at Heidelberg University and the University of Berlin in Germany and Oxford University in England. a

Mr. Short was a professor of ethics, psychology and political philosophy at Southwestern College in Winfield, Kan., in the 1920s.

He was president emeritus of the National Rivers and Harbors Congress.

He is survived by his wife, Helen, of the home, and two sisters, Helen Pauley, of West Palm Beach, Fla., and Fan Vineyard, of Galena.