PRESS GALLERY: Congress and the Washington Correspondents by Donald A. Ritchie (Harvard University Press: $29.95; 293 pp.). It's appropriate that Donald Ritchie, a historian for the U.S. Senate, commences "Press Gallery" by pointing out that the House of Representatives considered barring journalists from its floor just 24 hours after approving the First Amendment more than 200 years ago. The politicians' ambivalent attitude toward the news profession runs throughout this volume, and Ritchie demonstrates, between the lines, that the ambivalence derived to a significant degree from the amateur status of the Washington correspondents (most also served as committee clerks, lobbyists and political advisers). "Press Gallery" can be read as a history of journalism's professionalization, which occurred surprisingly late. Ritchie confirms the common idea that Washington is a corrupting place, and especially so for the journalist constantly facing (in the words of Marquis Childs) the "temptation to be a player, not just an observer."