Rare posters of pharmaceutical products are among fine prints, drawings, caricatures and trade cards on display at the Philadelphia Museum of Art. The posters tout cures for arthritis, coughs and colds--and even bad breath. They are part of the collection of William Helfand, longtime employee of a pharmaceutical company in Paris. The pharma posters are rare because they promote products carried by certain pharmacies, operating in limited areas. Among the earliest is an American poster advertising quinine bitters from 1846. Review