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 Form S-8 (File Nos. 333-31709, 333-31721, 333-31723 and 333-31727). ARTHUR ANDERSEN LLP /s/ Arthur Andersen LLP San Antonio, Texas February 26, 1998