Front: FIRST DAY OF ISSUE MERCK & CO. PHOTO AAC Στον Art Craft LEER 75th Anniversary CHEMICAL SOCIETY 413N HORK SEP 4 9-AM 1951 N.N AMERICAN CHEMICAL SOCIETY DIAMOND 1876 AAC JUBILEE 1951 3CU.S.POSTAGE 30 FIRST DAY OF ISSUE Back: 102 1/THA