Exhibit 23.1 CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS As independent public accountants, we hereby consent to the incorporation of our reports dated July 21, 1997 included in this Form 10-Q, into the Company's previously filed Registration Statements on Forms S-3 (File No. 333-20991 and File No. 333-20999) and Forms S-8 (File No. 333-14243 and File No. 333-28427). ARTHUR ANDERSEN LLP Philadelphia, Pa., August 13, 1997