Exhibit 23.1 CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS As independent public accountants, we hereby consent to the incorporation of our report included in this Form 10-K, into the Company's previously filed Registration Statements on Forms S-3 (File No. 333-20999, File No. 333-39155 and File No. 333-46647) and Forms S-8 (File No. 333-14243 and File No. 333-28427). ARTHUR ANDERSEN LLP Philadelphia, PA March 30, 1998