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                                                                    EXHIBIT 4.14



                          Supplemental Indenture No. 2



               This Supplemental Indenture No. 2, dated as of March 6, 1998
(this "Supplemental Indenture"), among Beckman Instruments (Naguabo) Inc., a
California corporation, Hybritech Incorporated, a California corporation,
SmithKline Diagnostics, Inc., a Delaware corporation, Coulter Corporation, a
Delaware corporation, and Coulter Leasing Corporation, an Illinois corporation
(the "Debenture Guarantors"), Beckman Instruments, Inc., a Delaware corporation
(together with its successors and assigns, the "Company"), and The First
National Bank of Chicago (the "Trustee"), as Trustee under the Indenture
referred to below.


                               W I T N E S S E T H


               WHEREAS, the Company and the Trustee have heretofore become
parties to an Indenture, dated as of May 15, 1996 (as amended, supplemented,
waived or otherwise modified, the "Indenture");

               WHEREAS, Section 1011 of the Indenture provides that under
certain circumstances the Company is required to cause a Debenture Guarantor to
execute and deliver to the Trustee a supplemental indenture pursuant to which
the Debenture Guarantor shall guarantee the Company's obligations under the
Debentures pursuant to a series of Securities on the terms and conditions set
forth herein; and

               WHEREAS, the Debenture Guarantors are executing this Supplemental
Indneture pursuant to which the Debenture Guarantors will guarantee the
Company's obligations under its 7.05% Debentures due June 1, 2026 (the
"Securities") on the terms and conditions set forth herein; and

               WHEREAS, pursuant to Sections 901 and 1011 of the Indenture, the
parties hereto are authorized to execute and deliver this Supplemental Indenture
to amend the Indenture, without the consent of any Holder;

               NOW, THEREFORE, in consideration of the foregoing and for other
good and valuable consideration, the receipt of which is hereby acknowledged,
the Debenture Guarantor, the Company, the other Debenture Guarantors, if any,
and the Trustee mutually covenant and agree for the benefit of the Holders of
the Securities as follows:



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                                   ARTICLE I.
                                   DEFINITIONS

SECTION 1.1.   DEFINED TERMS.

               Capitalized terms used herein and not otherwise defined herein
have the meanings assigned to them in the Indenture. The words "herein,"
"hereof" and "hereby" and other words of similar import used in this
Supplemental Indenture refer to this Supplemental Indenture as a whole and not
to any particular section hereof.

                                   ARTICLE II.
                             AGREEMENT TO GUARANTEE

SECTION 2.1.   AGREEMENT TO GUARANTEE.

               The Debenture Guarantor hereby agrees to be bound by all
applicable provisions of the Indenture as a Debenture Guarantor and to guarantee
the Company's obligations under the Indenture and the Securities on the terms
and subject to the conditions set forth below:

        SECTION 2.1.1 UNCONDITIONAL GUARANTEE.

                      (a) Each Debenture Guarantor hereby jointly and severally
        and fully and unconditionally guarantees to each Holder of a Security
        authenticated and delivered by the Trustee and its successors and
        assigns that: (1) the principal of, and premium, if any, and interest
        on, the Securities of each series will be duly and punctually paid in
        full when due, whether at maturity, by acceleration or otherwise, and
        interest on the overdue principal and (to the extent permitted by law)
        interest, if any, on the Securities of each series and all other
        obligations of the Company or the Debenture Guarantors to the Holders or
        the Trustee hereunder and thereunder (including fees, expenses or other)
        and all other Indenture Obligations will be promptly paid in full or
        performed, all in accordance with the terms hereof; and (2) in case of
        any extension of time of payment or renewal of any Securities of either
        series or any of such other Indenture Obligations with respect to the
        Securities of either series, the same will be promptly paid in full when
        due in accordance with the terms of the extension or renewal, whether at
        Stated Maturity, by acceleration or otherwise. Failing payment when due
        of any amount so guaranteed, or failing performance of any other
        obligation of the Company to the Holders of Securities of either series,
        for whatever reason, each Debenture Guarantor will be obligated to pay
        or cause the payment of, or to perform or cause the performance of, the
        same immediately. An Event of Default under this Indenture or the
        Securities of either series shall constitute an event of default under
        this Debenture Guarantee, and shall entitle the Holders of Securities of
        such series to accelerate the obligations of the Debenture Guarantor
        hereunder in the same manner and to the same extent as the obligations
        of the Company.



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                      Each Debenture Guarantor hereby agrees that its
        obligations hereunder shall be unconditional, irrespective of the
        validity, regularity or enforceability of this Indenture, the Securities
        of either series or the obligations of the Company or any other
        Debenture Guarantor to the Holders or the Trustee hereunder or
        thereunder, the absence of any action to enforce the same, any waiver or
        consent by any Holder of Securities with respect to any provisions
        hereof or thereof, any release of any other Debenture Guarantor, the
        recovery of any judgment against the Company, any action to enforce the
        same, whether or not a Debenture Guarantee is affixed to any particular
        Security, or any other circumstance which might otherwise constitute a
        legal or equitable discharge or defense of a guarantor.

                      Each Debenture Guarantor hereby waives the benefit of
        diligence, presentment, demand of payment, filing of claims with a court
        in the event of insolvency or bankruptcy of the Company, any right to
        require a proceeding first against the Company, protest, notice and all
        demands whatsoever and covenants that (except as otherwise provided in
        Section 2.1.2) its Debenture Guarantee will not be discharged except by
        complete performance of the obligations contained in the Securities,
        this Indenture and this Debenture Guarantee. This Debenture Guarantee is
        a guarantee of payment and not of collection. Each Debenture Guarantor
        further agrees that, as between it, on the one hand, and the Holders of
        Securities and the Trustee, on the other hand (1) subject to this
        Section 2.1, the maturity of the obligations guaranteed hereby may be
        accelerated as and to the extent provided in Article Five of the
        Indenture for the purposes of this Debenture Guarantee, notwithstanding
        any stay, injunction or other prohibition preventing such acceleration
        in respect of the obligations guaranteed hereby, and (2) in the event of
        any acceleration of such obligations as provided in Article Five of the
        Indenture, such obligations (whether or not due and payable) shall
        forthwith become due and payable by such Debenture Guarantor for the
        purpose of this Debenture Guarantee. Neither the Trustee nor any other
        Person shall have any obligation to enforce or exhaust any rights or
        remedies or to take any other steps under any security for the Indenture
        Obligations or against the Company or any other Person or any property
        of the Company or any other Person before the Trustee is entitled to
        demand payment and performance by any or all Debenture Guarantors of
        their liabilities and obligations under their respective Debenture
        Guarantees or under this Indenture.

                      Until terminated in accordance with Section 2.1.2, this
        Debenture Guarantee shall remain in full force and effect and continue
        to be effective should any petition be filed by or against the Company
        for liquidation or reorganization, should the Company become insolvent
        or make an assignment for the benefit of creditors or should a receiver
        or trustee be appointed for all or any significant part of the Company's
        assets, and shall, to the fullest extent permitted by law, continue to
        be effective or be reinstated, as the case may be, if at any time
        payment and performance of the Securities of either series are, pursuant
        to applicable law, rescinded or reduced in amount, or



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        must otherwise be restored or returned by any obligee on such
        Securities, whether as a "voidable preference," "fraudulent transfer" or
        otherwise, all as though such payment or performance had not been made.
        In the event that any payment, or any part thereof, is rescinded,
        reduced, restored or returned, the Securities of the relevant series
        shall, to the fullest extent permitted by law, be reinstated and deemed
        reduced only by such amount paid and not so rescinded, reduced, restored
        or returned.

                      (b) Each Debenture Guarantor that makes a payment or
        distribution under this Debenture Guarantee shall have the right to seek
        contribution from any non-paying Debenture Guarantor so long as the
        exercise of such right does not impair the rights of the Holders under
        this Debenture Guarantee.

                      (c) Notwithstanding any of the foregoing, each Debenture
        Guarantor's liability under this Debenture Guarantee shall be limited to
        the maximum amount that would not result in this Debenture Guarantee
        constituting a fraudulent conveyance or fraudulent transfer under
        applicable law.

                      (d) Each Debenture Guarantor acknowledges that it will
        receive direct and indirect benefits from the financing arrangements
        contemplated by this Indenture and that its Debenture Guarantee, and the
        waiver set forth in Section 2.1.3, is knowingly made in contemplation of
        such benefits.

        SECTION 2.1.2. RELEASE OF A DEBENTURE GUARANTEE.

                      (a) Any Debenture Guarantor shall be automatically and
        unconditionally released and discharged from all of its obligations
        under its Debenture Guarantee, and such Debenture Guarantee shall
        terminate, at any such time that such Debenture Guarantor is released
        and discharged from all of its obligations under all of its Guarantees
        in respect of Bank Indebtedness, unless such release results from
        payment under such Guarantee. Upon the delivery by the Company to the
        Trustee of an Officers' Certificate and, if requested by the Trustee, an
        Opinion of Counsel to the effect that the transaction giving rise to
        such release of such Debenture Guarantee was made by the Company in
        accordance with the provisions of this Indenture and the Securities, the
        Trustee shall execute any documents reasonably required in order to
        evidence such release and discharge of such Debenture Guarantor from its
        obligations under and termination of its Debenture Guarantee.

                      (b) Upon the sale, exchange or transfer to any Person not
        an Affiliate of the Company of all of the Capital Stock held by the
        Company and its Subsidiaries in, or all or substantially all the assets
        of, a Debenture Guarantor (which sale, exchange or transfer is not
        prohibited by this Indenture), such Debenture Guarantor shall be
        automatically and unconditionally released and discharged from all its
        obligations under its Debenture Guarantee, and such Debenture Guarantee
        shall terminate. Upon such



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        occurrence, the Trustee shall execute any documents reasonably required
        in order to evidence such release, discharge and termination in respect
        of such Debenture Guarantee.

                      (c) Upon the release of any Debenture Guarantor from its
        Debenture Guarantee pursuant to the provisions of the Indenture, each
        other Debenture Guarantor not so released shall remain liable for the
        full amount of principal of, and premium, if any, and interest on, the
        Securities as and to the extent provided in this Section 2.1.

                      (d) Each Debenture Guarantee shall terminate and cease to
        be of further effect upon (i) defeasance of the Company's obligations in
        accordance with Section 1402 of the Indenture and (ii) satisfaction and
        discharge of this Indenture in accordance with Section 401 of the
        Indenture.

        SECTION 2.1.3. WAIVER OF SUBROGATION.

                      Each Debenture Guarantor hereby irrevocably waives any
        claim or other rights which it may now or hereafter acquire against the
        Company that arise from the existence, payment, performance or
        enforcement of the Company's obligations under the Securities of either
        series and this Indenture or such Debenture Guarantor's obligations
        under its Debenture Guarantee and this Indenture, including, without
        limitation, any right of subrogation, reimbursement, exoneration,
        indemnification, and any right to participate in any claim or remedy of
        any Holder of Securities of either series against the Company, whether
        or not such claim, remedy or right arises in equity, or under contract,
        statute or common law, until this Indenture is discharged and all of the
        Securities of both series are discharged and paid in full. If any amount
        shall be paid to any Debenture Guarantor in violation of the preceding
        sentence and the Securities of the relevant series shall not have been
        paid in full, such amount shall have been deemed to have been paid to
        such Debenture Guarantor for the benefit of, and held in trust for the
        benefit of, the Holders of the Securities of such series, and shall
        forthwith be paid to the Trustee for the benefit of such Holders to be
        credited and applied upon such Securities, whether matured or unmatured,
        in accordance with the terms of this Indenture.

        SECTION 2.1.4. RELIANCE ON JUDICIAL ORDER OR CERTIFICATE OF LIQUIDATING
                       AGENT REGARDING DISSOLUTION, ETC.

                      Upon any payment or distribution of assets of any
        Debenture Guarantor referred to in this Section 2.1, the Trustee,
        subject to the provisions of Section 601 of the Indenture, and the
        Holders of Securities of either series shall be entitled to rely upon
        any order or decree entered by any court of competent jurisdiction in
        which such insolvency, bankruptcy, receivership, liquidation,
        reorganization, dissolution, winding-up or similar case or proceeding is
        pending, or a certificate of the trustee in



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        bankruptcy, receiver, liquidating trustee, custodian, assignee for the
        benefit of creditors, agent or other Person making such payment or
        distribution, delivered to the Trustee or to such Holders, for the
        purpose of ascertaining the Persons entitled to participate in such
        payment or distribution, the holders of other Indebtedness of such
        Debenture Guarantor, the amount thereof or payable thereon, the amount
        or amounts paid or distributed thereon and all other facts pertinent
        thereto or to this Section 2.1; provided that the foregoing shall apply
        only if such court has been fully apprised of the provisions of this
        Section 2.1.

        SECTION 2.1.5. SECTION 2.1 APPLICABLE TO PAYING AGENTS.

                      In case at any time any Paying Agent other than the
        Trustee shall have been appointed by the Company and be then acting
        hereunder, the term `Trustee' as used in this Section 2.1 shall in such
        case (unless the context otherwise requires) be construed as extending
        to and including such Paying Agent within its meaning as fully for all
        intents and purposes as if such Paying Agent were named in this Section
        2.1 in addition to or in place of the Trustee.

        SECTION 2.1.6. NO SUSPENSION OF REMEDIES.

                      Nothing contained in this Section 2.1 shall limit the
        right of the Trustee or the Holders of Securities of either series to
        take any action to accelerate the maturity of such Securities pursuant
        to Article Five of the Indenture or to pursue any rights or remedies
        hereunder or under applicable law.

                                  ARTICLE III.
                                  MISCELLANEOUS

SECTION 3.1.   TERMINATION.

               The Debenture Guarantor's Debenture Guarantee shall terminate and
be of no further force or effect, and the Debenture Guarantor shall be released
and discharged from all obligations in respect of such Debenture Guarantee, as
and when provided in Section 2.1.2.

SECTION 3.2.   PARTIES.

               Nothing in this Supplemental Indenture is intended or shall be
construed to give any Person, other than the Holders and the Trustee, any legal
or equitable right, remedy or claim under or in respect of the Debenture
Guarantor's Debenture Guarantee or any provision contained herein or in Section
2.1.



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SECTION 3.3.   GOVERNING LAW.

               THIS SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK (WITHOUT GIVING EFFECT TO THE
CONFLICT OF LAWS PRINCIPLES THEREOF, OTHER THAN ANY MANDATING THE APPLICATION OF
SUCH LAWS).

SECTION 3.4.   RATIFICATION OF INDENTURE; SUPPLEMENTAL INDENTURES PART OF
               INDENTURE.

               Except as expressly amended hereby, the Indenture is in all
respects ratified and confirmed and all the terms, conditions and provisions
thereof shall remain in full force and effect. This Supplemental Indenture shall
form a part of the Indenture for all purposes, and every Holder of Securities
heretofore or hereafter authenticated and delivered shall be bound hereby. The
Trustee makes no representation or warranty as to the validity or sufficiency of
this Supplemental Indenture.

SECTION 3.5.   COUNTERPARTS.

               The parties hereto may sign one or more copies of this
Supplemental Indenture in counterparts, all of which together shall constitute
one and the same agreement.

SECTION 3.6.   HEADINGS.

               The section headings herein are for convenience of reference only
and shall not be deemed to alter or affect the meaning or interpretation of any
provisions hereof.



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               IN WITNESS WHEREOF, the parties hereto have caused this
Supplemental Indenture to be duly executed, and their respective corporate seals
to be hereunto affixed and attested, all as of the date first above written.

                                        BECKMAN INSTRUMENTS, INC.


                                        By:  /s/ Dennis K. Wilson
                                             -----------------------------------
                                             Name:  Dennis K. Wilson
                                             Title: Vice President, Finance and
Attest:                                             Chief Financial Officer


--------------------------

                                        THE FIRST NATIONAL BANK OF CHICAGO


                                        By:  /s/ Leland Hansen
                                             -----------------------------------
                                             Name:  Leland Hansen
Attest:                                      Title: Assistant Vice President


--------------------------

                                        BECKMAN INSTRUMENTS (NAGUABO) INC.


                                        By:  /s/ William H. May
                                             -----------------------------------
                                             Name:  William H. May
Attest:                                      Title: Vice President and Secretary


--------------------------

                                        HYBRITECH INCORPORATED


                                        By:  /s/ William H. May
                                             -----------------------------------
                                             Name:  William H. May
Attest:                                      Title: Vice President and Secretary


--------------------------



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                                        SMITHKLINE DIAGNOSTICS, INC.


                                        By:  /s/ Dennis K. Wilson
                                             -----------------------------------
                                             Name:  Dennis K. Wilson
Attest:                                      Title: Vice President, Finance and
                                                    Chief Financial Officer

--------------------------

                                        COULTER CORPORATION


                                        By:  /s/ William H. May
                                             -----------------------------------
                                             Name:  William H. May
Attest:                                      Title: Vice President and
                                                    Assistant Secretary

--------------------------

                                        COULTER LEASING CORPORATION


                                        By:  /s/ William H. May
                                             -----------------------------------
                                             Name:  William H. May
Attest:                                      Title: Vice President and
                                                    Assistant Secretary

--------------------------



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