
<PAGE>

                                        COMMON STOCK


NUMBER              [PHOTO]               ALLEGIANCE                      SHARES


                 SEE REVERSE FOR CERTAIN DEFINITIONS
                                   CUSIP 017475 10 4


                             ALLEGIANCE CORPORATION

              INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE
     THIS CERTIFICATE IS TRANSFERABLE IN THE CITY OF NEW YORK OR IN CHICAGO






      FULLY PAID AND NON-ASSESSABLE SHARES OF COMMON STOCK OF THE PAR VALUE
                           OF ONE DOLLAR PER SHARE OF

                              CERTIFICATE OF STOCK

     WITNESS THE SEAL OF THE CORPORATION AND THE FACSIMILE SIGNATURES OF ITS
     DULY AUTHORIZED OFFICERS

DATED:
                                   ALLEGIANCE
COUNTERSIGNED AND REGISTERED:      CORPORATION
     FIRST CHICAGO TRUST COMPANY    CORPORATE             /s/ Lester B. Knight
      OF NEW YORK                     SEAL
                TRANSFER AGENT      DELAWARE
                 AND REGISTRAR                         CHAIRMAN OF THE BOARD AND
                                                       CHIEF EXECUTIVE OFFICER
BY   /s/ Joseph F. Sandifer
                                                      /s/ William L. Feather
          AUTHORIZED SIGNATURE
                                                                       SECRETARY

<PAGE>

     ALLEGIANCE CORPORATION WILL FURNISH WITHOUT CHARGE TO EACH STOCKHOLDER WHO
SO REQUESTS A STATEMENT OF THE DESIGNATIONS, PREFERENCES AND RELATIVE,
PARTICIPATING, OPTIONAL OR OTHER SPECIAL RIGHTS OF EACH CLASS OF STOCK OR SERIES
THEREOF WHICH IT IS AUTHORIZED TO ISSUE AND THE QUALIFICATIONS, LIMITATIONS OR
RESTRICTIONS OF SUCH PREFERENCES AND/OR RIGHTS. ANY SUCH REQUEST IS TO BE
ADDRESSED TO THE SECRETARY OF ALLEGIANCE CORPORATION OR TO THE TRANSFER AGENT.

For value received, ______________________ hereby sell, assign and transfer unto

   PLEASE INSERT SOCIAL SECURITY OR OTHER
      IDENTIFYING NUMBER OF ASSIGNEE
____________________________________________

________________________________________________________________________________

________________________________________________________________________________
                  (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS,
                     INCLUDING POSTAL ZIP CODE, OF ASSIGNEE)

________________________________________________________________________________

________________________________________________________________________________

_________________________________________________________________________ Shares
of the stock represented by the within Certificate, and do hereby irrevocably
constitute and appoint _________________________________________________________

________________________________________________________________________________
Attorney to transfer the said stock on the Books of the within-named Corporation
with full power of substitution in the premises.

Dated __________________________________

                         _______________________________________________________
                              NOTICE: THE SIGNATURE TO THIS ASSIGNMENT MUST
                              CORRESPOND WITH THE NAME AS WRITTEN UPON THE FACE
                              OF THE CERTIFICATE IN EVERY PARTICULAR WITHOUT
                              ALTERATION OR ENLARGEMENT OR ANY CHANGE WHATEVER.

