I couldn't find any on-line sources. You should be looking in the city directory for the year(s) in question, but they appear to exist only in hard copy. The Boston Public Library (main branch, on Boylston St.) maintains copies. The state library (at the State House on Beacon St.) has some as well. The City of Boston, where I thought to look first, didn't list them, but may have them available, too. The BPL also keeps copies of telephone books from bygone years. The Yellow Pages might help you there. Washington St. is quite long, so you will have to get a better feel for what neighborhood you're looking at. Identifying the cross streets nearby should help. BTW, you're missing all my favorites from that era: the Boston Tea Party, the Rathskellar ("the Rat"), Paul's Mall/the Jazz Workshop, the Eliot Lounge... They were in the Back Bay/Kenmore area.