John C. Watson, 78, an attorney handling adoption matters for the D.C. Legal Aid Society, died Tuesday at his home in Washington after a heart attack.

He had been with the society since 1966.

Born in Crystal Falls, Mich., Mr. Watson was a graduate of the University of Michigan. He received a doctor of jurisprudence degree from the University of Florida in 1926.

After practicing law for two years in Florida, he returned to Crystal Falls, where he was in practice until 1939. He then earned a master's degree in political science from the University of Michigan.

Mr. Watson came to Washington in 1941 to serve with the Federal Rubber Reserve Corporation during World War II.

After the war, he went to Germany as a civilian employee of the War Department and served on legal and military teams working with the Allied Control Authority. He resumed his law practice in Crystal Falls in 1948, retiring in 1964.

Mr. Watson was a member of the Michigan, Florida and D.C. bars. He belonged to the Civil War Round Table.

He is survived by his wife, Edna Little Watson, of the home; two sons, Richard M. C. Watson and Dr. Charles H. Watson II, both of Washington, and six grandchildren.