EXHIBIT 23

                    CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS


As independent  public  accountants,  we hereby consent to the  incorporation by
reference of our reports dated January 22, 1998,  included in this Form 10-K for
the year ended  December  31,  1997,  into the  Corporation's  previously  filed
Registration  Statements Nos. 33-40136 and 33-64217 on Form S-3 and 33-22581, as
amended, 33-22930,  33-36303, 33-52573, 33-52715, 33-63554 and 33-65383 on Form
S-8.



                                                     /s/ Arthur Andersen LLP
                                                     -----------------------
                                                     ARTHUR ANDERSEN LLP

Chicago, Illinois
January 22, 1998