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                                                                     EXHIBIT 4.9

                                                                       EXHIBIT F


                                     FORM OF
            FOURTH AMENDED AND RESTATED SUBSIDIARIES PLEDGE AGREEMENT


                  FOURTH AMENDED AND RESTATED PLEDGE AGREEMENT, dated as of July
  , 1999, made by each of the undersigned corporations (each, a "Pledgor", and
collectively, the "Pledgors") in favor of The Chase Manhattan Bank, as
Administrative Agent (in such capacity, the "Administrative Agent"), for the
banks and other financial institutions (the "Lenders") from time to time parties
to the Third Amended and Restated Credit Agreement, dated as of July   , 1999
(as amended, supplemented or otherwise modified from time to time, the "Credit
Agreement"), among Sybron International Corporation, a Wisconsin corporation
("the Parent"), Ormco Corporation, a Delaware corporation ("Ormco"), Kerr
aCorporation, a Delaware corporation ("Kerr"), Nalge Nunc International
Corporation, a Delaware corporation ("NNI"), Erie Scientific Company, a Delaware
corporation ("Erie"), Barnstead Thermolyne Corporation, a Delaware corporation
("Barnstead"), Remel Inc., a Wisconsin corporation ("Remel"; Ormco, Kerr, NNI,
Erie, Barnstead and Remel are collectively referred to herein as the "Subsidiary
Borrowers"), the Lenders, the Administrative Agent and Chase Securities Inc., as
arranger.


                              W I T N E S S E T H:


                  WHEREAS, each Pledgor is the legal and beneficial owner of the
shares of Pledged Stock (as hereinafter defined) hereby pledged by such Pledgor;

                  WHEREAS, each Pledgor is the legal and beneficial owner of
each of the Pledged Notes (as hereinafter defined) hereby pledged by such
Pledgor; and

                  NOW, THEREFORE, in consideration of the premises and to induce
the Administrative Agent and the Lenders to enter into the Credit Agreement and
to induce the Lenders to make their respective extensions of credit to the
Parent and Subsidiary Borrowers under the Credit Agreement, each Pledgor hereby
agrees with the Administrative Agent, for the ratable benefit of the Lenders, as
follows:

                  1.   Defined Terms. (a) Unless otherwise defined herein, terms
defined in the Credit Agreement or the Subsidiaries Guarantee and used herein
are so used as so defined.

                  (b)  The following terms shall have the following meanings:

                  "Agreement": this Fourth Amended and Restated Pledge
         Agreement, as the same may be amended, modified or otherwise
         supplemented from time to time.

                  "Code": the Uniform Commercial Code from time to time in
         effect in the State of New York.



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                  "Collateral": the Pledged Stock, the Pledged Notes and all
         Proceeds.

                  "Issuers": the collective reference to the companies
         identified on Schedule 1 hereto as the issuers of the Pledged Stock.

                  "Obligations" means (a) as to any Pledgor, all of its
         obligations and liabilities (i) under the Subsidiaries Guarantee,
         subject to the limitations on liability contained therein and (ii) to
         any Lender or an Affiliate of any Lender under or in connection with
         any Interest Rate Agreement or foreign exchange contract and (b)
         without duplication, as to any Pledgor which is a Subsidiary Borrower,
         the unpaid principal of and interest on (including, without limitation,
         interest accruing after the maturity of the Loans made to such Pledgor
         and interest accruing on or after the filing of any petition in
         bankruptcy, or the commencement of any insolvency, reorganization or
         like proceeding, relating to such Pledgor, whether or not a claim for
         post-filing or post-petition interest is allowed in such proceeding)
         the Notes of such Pledgor and all other obligations and liabilities of
         such Pledgor to the Administrative Agent or to the Lenders, whether
         direct or indirect, absolute or contingent, due or to become due, or
         now existing or hereafter incurred, which may arise under, out of, or
         in connection with, the Credit Agreement, the Notes, any other Loan
         Document and any other document made, delivered or given in connection
         herewith or therewith, whether on account of principal, interest,
         reimbursement obligations, fees, indemnities, costs, expenses
         (including, without limitation, all fees and disbursements of counsel
         to the Administrative Agent or to the Lenders) or otherwise; where the
         context requires, "Obligations" refers to the Obligations (as defined
         herein) of each and every Pledgor.

                  "Obligors": the collective reference to the companies
         identified on Schedule 2 hereto, as such Schedule may be amended from
         time to time.

                  "Pledged Notes": the promissory note or notes of the Obligors
         identified on Schedule 2, together with all substitutes, replacements
         or refinancings thereto that may be issued or granted by any Obligor to
         any Pledgor while this Agreement is in effect.

                  "Pledged Stock": the shares of capital stock or other equity
         interests listed on Schedule 1 hereto, together with all stock
         certificates, options or rights of any nature whatsoever that may be
         issued or granted by any Issuer to any Pledgor in respect of the
         Pledged Stock while this Agreement is in effect.

                  "Proceeds": all "proceeds" as such term is defined in Section
         9-306(1) of the Uniform Commercial Code in effect in the State of New
         York on the date hereof and, in any event, shall include, without
         limitation, all dividends or other income from the Pledged Stock and
         the Pledged Notes, collections thereon or distributions with respect
         thereto.

                  "Securities Act": the Securities Act of 1933, as amended.

                  (c) The words "hereof," "herein" and "hereunder" and words of
similar import when used in this Agreement shall refer to this Agreement as a
whole and not to any particular

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provision of this Agreement, and Section and paragraph references are to this
Agreement unless otherwise specified.

                  (d) The meanings given to terms defined herein shall be
equally applicable to both the singular and plural forms of such terms.

                  2. Pledge; Grant of Security Interest. Each Pledgor hereby
delivers to the Administrative Agent, for the ratable benefit of the Lenders,
all of the Pledged Stock (except such Pledged Stock which is not certificated)
and the Pledged Notes listed with its name on Schedule 1 or Schedule 2 hereto,
as the case may be, and hereby grants to the Administrative Agent, for the
ratable benefit of the Lenders, a first security interest in the Collateral
granted by such Pledgor, as collateral security for the prompt and complete
payment and performance when due (whether at the stated maturity, by
acceleration or otherwise) of the Obligations of such Pledgor.

                  3. Stock Powers and Allonges. (a) Concurrently with the
delivery to the Administrative Agent of each certificate representing one or
more shares of Pledged Stock to the Administrative Agent, the relevant Pledgor
shall deliver an undated stock power covering such certificate, duly executed in
blank by such Pledgor with, if the Administrative Agent so requests, signature
guaranteed.

                  (b) Concurrently with the delivery to the Administrative Agent
of each note representing one of the Pledged Notes, the relevant Pledgor shall
deliver executed allonges endorsing such notes to "Bearer" with, if the
Administrative Agent so requests, signature guaranteed.

                  4. Representations and Warranties. Each Pledgor represents and
warrants that:

                  (a) except as set forth on Schedule 1 hereto, the shares of
Pledged Stock of such Pledgor constitute all the issued and outstanding shares
of all classes of the capital stock of the Issuers thereof; provided, however,
that the parties acknowledge that the capital stock of Microgenics Corporation
has not been pledged hereunder nor have the shares of capital stock of entities
which do not meet the criteria set forth in the definition of Pledge Guidelines
or which otherwise constitute the capital stock of a Specified Entity.

                  (b) the Pledged Notes of such Pledgor constitute all of the
issued and outstanding promissory notes payable by the Parent and the direct and
indirect Subsidiaries of the Parent (other than such Pledgor) to such Pledgor;

                  (c) all the shares of such Pledged Stock have been duly and
validly issued and are fully paid and nonassessable (except as provided in Wis.
Stat. ss.180.0622(2)); and each of such Pledged Notes has been duly and validly
issued and is the legal, valid and binding obligation of the maker thereof,
enforceable in accordance with its terms, except as affected by bankruptcy,
insolvency, fraudulent conveyance, reorganization, moratorium and other similar
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laws relating to or affecting creditors' rights generally, general equitable
principles (whether considered in a proceeding in equity or at law) and an
implied covenant of good faith and fair dealing;

                  (d) such Pledgor is the record and beneficial owner of, and
has good and marketable title to, such Pledged Stock and Pledged Notes, free of
any and all Liens or options in favor of, or claims of, any other Person, except
the security interest created by this Agreement;

                  (e) upon delivery to the Administrative Agent of the stock
certificates evidencing such Pledged Stock (or in the case of certain Issuers
organized under foreign jurisdictions, the deed or other document evidencing
such Pledged Stock) and upon delivery to the Administrative Agent of such
Pledged Notes, the security interest created by this Agreement will constitute a
valid, perfected first priority security interest in the Collateral granted by
such Pledgor, enforceable in accordance with its terms against all creditors of
such Pledgor and any Persons purporting to purchase any Collateral from such
Pledgor, except as affected by bankruptcy, insolvency, fraudulent conveyance,
reorganization, moratorium and other similar laws relating to or affecting
creditors' rights generally, general equitable principles (whether considered in
a proceeding in equity or at law) and an implied covenant of good faith and fair
dealing;

                  (f) such Pledgor has obtained from each Issuer and has
delivered to the Administrative Agent an Acknowledgement and Consent,
substantially in the form attached hereto as Annex A, executed by each such
Issuer; and

                  (g) no consent or authorization of, filing with or other act
by or in respect of any Person is required in connection with the execution,
delivery, performance, validity or enforceability of such Pledged Notes, and
such Pledgor has fully performed all its obligations under such Pledged Notes.

                  5. Covenants. Each Pledgor covenants and agrees with the
Administrative Agent and the Lenders that, from and after the date of this
Agreement until the Obligations are paid in full and the Commitments are
terminated:

                  (a) If such Pledgor shall, as a result of its ownership of any
Pledged Stock, become entitled to receive or shall receive any stock certificate
(including, without limitation, any certificate representing a stock dividend or
a distribution in connection with any reclassification, increase or reduction of
capital or any certificate issued in connection with any reorganization), option
or rights, whether in addition to, in substitution of, as a conversion of, or in
exchange for any shares of any Pledged Stock, or otherwise in respect thereof,
such Pledgor shall accept the same as the agent of the Administrative Agent and
the Lenders, hold the same in trust for the Administrative Agent and the Lenders
and deliver the same forthwith to the Administrative Agent in the exact form
received, duly indorsed by such Pledgor to the Administrative Agent, if
required, together with an undated stock power covering such certificate duly
executed in blank by such Pledgor and with, if the Administrative Agent so
requests, signature guaranteed, to be held by the Administrative Agent, subject
to the terms hereof, as

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additional collateral security for the Obligations of such Pledgor. Any sums
paid to such Pledgor upon or in respect of any Pledged Stock or any Pledged
Notes upon the liquidation or dissolution of any Issuer or any Obligor, as the
case may be, shall be paid over to the Administrative Agent to be held by it
hereunder as additional collateral security for the Obligations of such Pledgor,
and in case any distribution of capital or payment of principal shall be made to
such Pledgor on or in respect of any Pledged Stock or any Pledged Notes or any
property shall be distributed upon or with respect to any Pledged Stock or any
Pledged Notes pursuant to the recapitalization or reclassification of the
capital of any Issuer or any Obligor, as the case may be, or pursuant to the
reorganization thereof, the property so distributed to such Pledgor shall be
delivered to the Administrative Agent to be held by it hereunder as additional
collateral security for the Obligations of such Pledgor. If any sums of money or
property so paid or distributed in respect of any Pledged Stock or any Pledged
Notes shall be received by such Pledgor, such Pledgor shall, until such money or
property is paid or delivered to the Administrative Agent, hold such money or
property in trust for the Lenders, segregated from other funds of such Pledgor,
as additional collateral security for the Obligations such Pledgor.
Notwithstanding the foregoing, in no event shall more than 65% of the issued and
outstanding shares of stock, or any property distributed in respect thereof, of
any Issuer which is a Controlled Foreign Corporation constitute collateral
security for the Obligations.

                  (b) Without the prior written consent of the Administrative
Agent, no Pledgor shall (1) vote to enable, or take any other action to permit,
any Issuer to issue any stock or other equity securities of any nature or to
issue any other securities convertible into or granting the right to purchase or
exchange for any stock or other equity securities of any nature of such Issuer
(2) sell, assign, transfer, exchange, or otherwise dispose of, or grant any
option with respect to, the Collateral, or (3) create, incur or permit to exist
any Lien or option in favor of, or any claim of any Person with respect to, any
of the Collateral, or any interest therein, except for the security interests
created by this Agreement and Liens permitted by the Credit Agreement. Each
Pledgor will defend the right, title and interest of the Administrative Agent
and the Lenders in and to the Collateral against the claims and demands of all
Persons whomsoever.

                  (c) At any time and from time to time, upon the written
request of the Administrative Agent to a Pledgor, and at the sole expense of
such Pledgor, such Pledgor will promptly and duly execute and deliver such
further instruments and documents and take such further actions as the
Administrative Agent may reasonably request for the purposes of obtaining or
preserving the full benefits of this Agreement and of the rights and powers
herein granted. If any amount payable under or in connection with any of the
Collateral shall be or become evidenced by any promissory note, other instrument
or chattel paper, such note, instrument or chattel paper shall be immediately
delivered to the Administrative Agent, duly endorsed in a manner satisfactory to
the Administrative Agent, to be held as Collateral pursuant to this Agreement.

                  (d) Each Pledgor shall pay, and save the Administrative Agent
and the Lenders harmless from, any and all liabilities with respect to, or
resulting from any delay in paying, any and all stamp, excise, sales or other
taxes which may be payable or determined to be


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payable with respect to any of the Collateral granted by such Pledgor or in
connection with any of the transactions contemplated by this Agreement.

                  (e) Each Pledgor will not (i) amend, modify, terminate or
waive any provision of any Pledged Note in any manner materially adverse to the
interests of the Administrative Agent or the Lenders, (ii) fail to exercise
promptly and diligently each and every material right which it may have under
any Pledged Note where such failure could reasonably be expected to have an
adverse affect on the interests of the Administrative Agent or the Lenders or
(iii) fail to deliver to the Administrative Agent a copy of each material
demand, notice or document received by it relating in any way to any Pledged
Note.

                  (f) Without the prior written consent of the Administrative
Agent, no Pledgor will grant any extension (other than, so long as no Default or
Event of Default shall exist, extensions granted in accordance with prudent
business judgment) of the time of payment of any Pledged Note, compromise,
compound or settle the same for less than the full amount thereof, release,
wholly or partially, any Person liable for the payment thereof, or allow any
credit or discount whatsoever thereon.

                  (g) Each Pledgor shall deliver to the Administrative Agent, in
the exact form received, to be held by the Administrative Agent, subject to the
terms hereof, as additional collateral security for the Obligations of such
Pledgor any additional promissory notes made by any Obligor for the benefit of
such Pledgor or other securities, options or rights received by it in
substitution or exchange for, or as a conversion of, or in addition to, any of
the Pledged Notes, or otherwise in respect thereof, together with an undated
endorsement or power, as the case may be, duly executed to the order of "Bearer"
or in blank, as the case may be, by such Pledgor and with, if the Administrative
Agent reasonably requests, signature guaranteed.

                  6. Cash Dividends; Voting Rights; Interest and Principal
Payments. (a) Unless an Event of Default shall have occurred and be continuing
and the Administrative Agent shall have given notice to a Pledgor of the
Administrative Agent's intent to exercise its corresponding rights pursuant to
Section 7 below, such Pledgor shall be permitted to receive all cash dividends
paid in the normal course of business and consistent with past practice, to the
extent permitted in the Credit Agreement, in respect of the Pledged Stock of
such Pledgor and to exercise all voting and corporate rights with respect to
such Pledged Stock; provided, however, that no vote shall be cast or corporate
right exercised or other action taken which, in the Administrative Agent's
reasonable judgment, would impair the Collateral or which would be inconsistent
with or result in any violation of any provision of the Credit Agreement, the
Notes, this Agreement or any other Loan Document.

                  (b) Unless an Event of Default shall have occurred and be
continuing and the Administrative Agent shall have given notice to a Pledgor of
the Administrative Agent's intent to exercise its corresponding rights pursuant
to Section 7 hereof, such Pledgor shall be permitted to receive and retain all
scheduled interest and principal payments on account of the Pledged Notes of
such Pledgor.



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                  7. Rights of the Lenders and the Administrative Agent. (a) If
an Event of Default shall occur and be continuing and the Administrative Agent
shall give notice of its intent to exercise such rights to a Pledgor, (1) the
Administrative Agent shall have the right to receive any and all cash dividends
paid in respect of the Pledged Stock of such Pledgor and any and all interest,
principal or other payments paid in respect of the Pledged Notes of such Pledgor
and make application thereof to the Obligations of such Pledgor in such order as
the Administrative Agent may determine, and (2) all shares of such Pledged Stock
shall be registered in the name of the Administrative Agent or its nominee, and
the Administrative Agent or its nominee may thereafter exercise (A) all voting,
corporate and other rights pertaining to such Pledged Stock at any meeting of
shareholders of any Issuer or otherwise and (B) any and all rights of
conversion, exchange, subscription and any other rights, privileges or options
pertaining to such Pledged Stock as if it were the absolute owner thereof
(including, without limitation, the right to exchange at its discretion any and
all of such Pledged Stock upon the merger, consolidation, reorganization,
recapitalization or other fundamental change in the corporate structure of any
Issuer, or upon the exercise by such Pledgor or the Administrative Agent of any
right, privilege or option pertaining to such Pledged Stock, and in connection
therewith, the right to deposit and deliver any and all of such Pledged Stock
with any committee, depositary, transfer agent, registrar or other designated
agency upon such terms and conditions as the Administrative Agent may determine)
and (3) the Administrative Agent or its nominee may thereafter exercise all
rights pertaining to such Pledged Notes (including without limitation, any and
all rights of conversion, exchange, subscription and any other rights,
privileges or options pertaining thereto) as if it were the absolute owner
thereof, all without liability except to account for property actually received
by it, but the Administrative Agent shall have no duty to such Pledgor to
exercise any such right, privilege or option and shall not be responsible for
any failure to do so or delay in so doing.

                  (b) Anything herein to the contrary notwithstanding, each
Pledgor shall remain liable under the Pledged Notes of such Pledgor to observe
and perform all the conditions and obligations to be observed and performed by
it thereunder all in accordance with the terms and provisions of such Pledged
Notes. Neither the Administrative Agent nor the Lenders shall have any
obligation or liability under any Pledged Note by reason of or arising out of
this Agreement or the receipt by the Administrative Agent or the Lenders of any
payment relating to such Pledged Note pursuant hereto (other than to account for
monies actually received by it), nor shall the Administrative Agent or any of
the Lenders be obligated in any manner to perform any of the obligations of any
Pledgor under or pursuant to any Pledged Note, to make any payment, to make any
inquiry as to the nature or the sufficiency of any payment received by it or as
to the sufficiency of any performance by any party under any Pledged Note, to
present or file any claim, to take any action to enforce any performance or to
collect the payment of any amounts which may have been assigned to it or to
which it may be entitled at any time or times.

                  (c) The rights of the Administrative Agent and the Lenders
hereunder shall not be conditioned or contingent upon the pursuit by the
Administrative Agent or any Lender of any right or remedy against any Issuer or
any Obligor or against any other Person which may be or become liable in respect
of all or any part of the Obligations or against any collateral security
therefor, guarantee thereof or right of offset with respect thereto. Neither the
Administrative

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Agent nor any Lender shall be liable for any failure to demand, collect or
realize upon all or any part of the Collateral or for any delay in doing so, nor
shall the Administrative Agent be under any obligation to sell or otherwise
dispose of any Collateral upon the request of a Pledgor or any other Person or
to take any other action whatsoever with regard to the Collateral or any part
thereof.

                  8. Remedies. If an Event of Default shall occur and be
continuing, the Administrative Agent, on behalf of the Lenders, may exercise, in
addition to all other rights and remedies granted in this Agreement and in any
other instrument or agreement securing, evidencing or relating to the
Obligations, all rights and remedies of a secured party under the Code. Without
limiting the generality of the foregoing, the Administrative Agent, without
demand of performance or other demand, presentment, protest, advertisement or
notice of any kind (except any notice required by law referred to below) to or
upon any Pledgor, any Issuer, any Obligor or any other Person (all and each of
which demands, defenses, advertisements and notices are hereby waived), may in
such circumstances forthwith collect, receive, appropriate and realize upon the
Collateral, or any part thereof, and/or may forthwith sell, assign, give option
or options to purchase or otherwise dispose of and deliver the Collateral or any
part thereof (or contract to do any of the foregoing), in one or more parcels at
public or private sale or sales, in the over-the-counter market, at any
exchange, broker's board or office of the Administrative Agent or any Lender or
elsewhere upon such terms and conditions as it may deem advisable and at such
prices as it may deem best, for cash or on credit or for future delivery without
assumption of any credit risk. The Administrative Agent or any Lender shall have
the right upon any such public sale or sales, and, to the extent permitted by
law, upon any such private sale or sales, to purchase the whole or any part of
the Collateral so sold, free of any right or equity of redemption in any
Pledgor, which right or equity is hereby waived or released. The Administrative
Agent shall apply any Proceeds from time to time held by it and the net proceeds
of any such collection, recovery, receipt, appropriation, realization or sale,
after deducting all reasonable costs and expenses of every kind incurred in
respect thereof or incidental to the care or safekeeping of any of the
Collateral or in any way relating to the Collateral or the rights of the
Administrative Agent and the Lenders hereunder, including, without limitation,
reasonable attorneys' fees and disbursements of counsel to the Administrative
Agent, to the payment in whole or in part of the Obligations, in such order as
the Administrative Agent may elect, and only after such application and after
the payment by the Administrative Agent of any other amount required by any
provision of law, including, without limitation, Section 9-504(1)(c) of the
Code, need the Administrative Agent account for the surplus, if any, to any
Pledgor. To the extent permitted by applicable law, each Pledgor waives all
claims, damages and demands it may acquire against the Administrative Agent or
any Lender arising out of the exercise by them of any rights hereunder, except
such claims and damages arising out of the gross negligence or willful
misconduct of the Administrative Agent or any such Lender. If any notice of a
proposed sale or other disposition of Collateral shall be required by law, such
notice shall be deemed reasonable and proper if given at least 10 days before
such sale or other disposition. Each Pledgor shall remain liable for any
deficiency if the proceeds of any sale or other disposition of Collateral are
insufficient to pay the Obligations of such Pledgor and the fees and
disbursements of any attorneys employed by the Administrative Agent or any
Lender to collect such deficiency.



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                  9.  Registration Rights; Private Sales. (a) If the
Administrative Agent shall determine to exercise its right to sell any or all of
the Pledged Stock of any Pledgor pursuant to paragraph 8 hereof, and if in the
opinion of the Administrative Agent it is necessary or advisable to have such
Pledged Stock, or that portion thereof to be sold, registered under the
provisions of the Securities Act, such Pledgor will cause the Issuer thereof to
(1) execute and deliver, and cause the directors and officers of such Issuer to
execute and deliver, all such instruments and documents, and do or cause to be
done all such other acts as may be, in the opinion of the Administrative Agent,
necessary or advisable to register such Pledged Stock, or that portion thereof
to be sold, under the provisions of the Securities Act, (2) to use its best
efforts to cause the registration statement relating thereto to become effective
and to remain effective for a period of one year from the date of the first
public offering of such Pledged Stock, or that portion thereof to be sold and
(3) to make all amendments thereto and/or to the related prospectus which, in
the opinion of the Administrative Agent, are necessary or advisable, all in
conformity with the requirements of the Securities Act and the rules and
regulations of the Securities and Exchange Commission applicable thereto. Such
Pledgor agrees to cause such Issuer to comply with the provisions of the
securities or "Blue Sky" laws of any and all jurisdictions which the
Administrative Agent shall designate and to make available to its security
holders, as soon as practicable, an earnings statement (which need not be
audited) which will satisfy the provisions of Section 11(a) of the Securities
Act.

                  (b) Each Pledgor recognizes that the Administrative Agent may
be unable to effect a public sale of any or all the Pledged Stock, by reason of
certain prohibitions contained in the Securities Act and applicable state
securities laws or otherwise, and may be compelled to resort to one or more
private sales thereof to a restricted group of purchasers which will be obliged
to agree, among other things, to acquire such securities for their own account
for investment and not with a view to the distribution or resale thereof. Such
Pledgor acknowledges and agrees that any such private sale may result in prices
and other terms less favorable than if such sale were a public sale and,
notwithstanding such circumstances, agrees that any such private sale shall be
deemed to have been made in a commercially reasonable manner. The Administrative
Agent shall be under no obligation to delay a sale of any of the Pledged Stock
for the period of time necessary to permit the Issuer thereof to register such
securities for public sale under the Securities Act, or under applicable state
securities laws, even if such Issuer would agree to do so.

                  (c) Each Pledgor further agrees to use its best efforts to do
or cause to be done all such other acts as may be necessary to make such sale or
sales of all or any portion of the Pledged Stock pursuant to this Section valid
and binding and in compliance with any and all other applicable Requirements of
Law. Such Pledgor further agrees that a breach of any of the covenants contained
in this Section will cause irreparable injury to the Administrative Agent and
the Lenders, that the Administrative Agent and the Lenders have no adequate
remedy at law in respect of such breach and, as a consequence, that each and
every covenant contained in this Section 9 shall be specifically enforceable
against such Pledgor, and such Pledgor hereby waives and agrees not to assert
any defenses against an action for specific performance of such covenants except
for a defense that no Event of Default has occurred under the Credit Agreement.



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                  10. Irrevocable Authorization and Instruction to Issuer and
Obligor. Each Pledgor hereby authorizes and instructs each Issuer of its Pledged
Stock and each Obligor of its Pledged Notes to comply with any instruction
received by it from the Administrative Agent in writing that (a) states that an
Event of Default has occurred and (b) is otherwise in accordance with the terms
of this Agreement, without any other or further instructions from such Pledgor,
and such Pledgor agrees that each such Issuer and each such Obligor shall be
fully protected in so complying.

                  11. Administrative Agent's Appointment as Attorney-in-Fact.
(a) Each Pledgor hereby irrevocably constitutes and appoints the Administrative
Agent and any officer or agent of the Administrative Agent, with full power of
substitution, as its true and lawful attorney-in-fact with full irrevocable
power and authority in the place and stead of such Pledgor and in the name of
such Pledgor or in the Administrative Agent's own name, from time to time in the
Administrative Agent's discretion, for the purpose of carrying out the terms of
this Agreement, to take any and all appropriate action and to execute any and
all documents and instruments which may be necessary or desirable to accomplish
the purposes of this Agreement, including, without limitation, any financing
statements, endorsements, assignments or other instruments of transfer.

                  (b) Each Pledgor hereby ratifies all that said attorneys shall
lawfully do or cause to be done pursuant to the power of attorney granted in
paragraph 11.(a). All powers, authorizations and agencies contained in this
Agreement are coupled with an interest and are irrevocable until the Obligations
are paid in full and the Commitments are terminated.

                  12. Duty of Administrative Agent. The Administrative Agent's
sole duty with respect to the custody, safekeeping and physical preservation of
the Collateral in its possession, under Section 9-207 of the Code or otherwise,
shall be to deal with it in the same manner as the Administrative Agent deals
with similar securities and property for its own account. Neither the
Administrative Agent, any Lender nor any of their respective directors,
officers, employees or agents shall be liable for failure to demand, collect or
realize upon any of the Collateral or for any delay in doing so or shall be
under any obligation to sell or otherwise dispose of any Collateral upon the
request of any Pledgor or any other Person or to take any other action
whatsoever with regard to the Collateral or any part thereof.

                  13. Execution of Financing Statements. Pursuant to Section
9-402 of the Code, each Pledgor authorizes the Administrative Agent to file
financing statements with respect to the Collateral without the signature of
such Pledgor in such form and in such filing offices as the Administrative Agent
reasonably determines appropriate to perfect the security interests of the
Administrative Agent under this Agreement.

                  14. Authority of Administrative Agent. Each Pledgor
acknowledges that the rights and responsibilities of the Administrative Agent
under this Agreement with respect to any action taken by the Administrative
Agent or the exercise or non-exercise by the Administrative Agent of any option,
voting right, request, judgment or other right or remedy provided for herein or
resulting or arising out of this Agreement shall, as between the Administrative
Agent and the Lenders, be governed by the Credit Agreement and by such other
agreements with respect thereto


<PAGE>   11
                                                                              11

as may exist from time to time among them, but, as between the Administrative
Agent and a Pledgor, the Administrative Agent shall be conclusively presumed to
be acting as agent for the Lenders with full and valid authority so to act or
refrain from acting, and neither any Pledgor, any Issuer nor any Obligor shall
be under any obligation, or entitlement, to make any inquiry respecting such
authority.

                  15. Notices. All notices, requests and demands to or upon the
Administrative Agent, any Pledgor, any Issuer or any Obligor to be effective
shall be in writing (or by telex, fax or similar electronic transfer confirmed
in writing) and shall be deemed to have been duly given or made (1) when
delivered by hand or (2) if given by mail, three days after being deposited in
the mail, postage prepaid, or (3) if by telex, fax or similar electronic
transfer, when sent and receipt has been confirmed, addressed to the
Administrative Agent at its address or transmission number for notices provided
in the Credit Agreement, to each Pledgor at its address or transmission number
for notices provided in the Subsidiaries Guarantee and to each Issuer and each
Obligor at its address set forth in its Acknowledgment and Consent. Any Pledgor,
any Issuer and any Obligor may change their addresses and transmission numbers
for notices by written notice to the Administrative Agent.

                  16. Severability. Any provision of this Agreement which is
prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction,
be ineffective to the extent of such prohibition or unenforceability without
invalidating the remaining provisions hereof, and any such prohibition or
unenforceability in any jurisdiction shall not invalidate or render
unenforceable such provision in any other jurisdiction.

                  17. Amendments in Writing; No Waiver; Cumulative Remedies. (a)
None of the terms or provisions of this Agreement as it affects any Pledgor may
be waived, amended, supplemented or otherwise modified except by a written
instrument executed by such Pledgor and the Administrative Agent, provided that
any provision of this Agreement may be waived by the Administrative Agent and
the Lenders in a letter or agreement executed by the Administrative Agent or by
telex or facsimile transmission from the Administrative Agent.

                  (b) Neither the Administrative Agent nor any Lender shall by
any act (except by a written instrument pursuant to paragraph 17(a) hereof),
delay, indulgence, omission or otherwise be deemed to have waived any right or
remedy hereunder or to have acquiesced in any Default or Event of Default or in
any breach of any of the terms and conditions hereof. No failure to exercise,
nor any delay in exercising, on the part of the Administrative Agent or any
Lender, any right, power or privilege hereunder shall operate as a waiver
thereof. No single or partial exercise of any right, power or privilege
hereunder shall preclude any other or further exercise thereof or the exercise
of any other right, power or privilege. A waiver by the Administrative Agent or
any Lender of any right or remedy hereunder on any one occasion shall not be
construed as a bar to any right or remedy which the Administrative Agent or such
Lender would otherwise have on any future occasion.

                  (c) The rights and remedies herein provided are cumulative,
may be exercised singly or concurrently and are not exclusive of any other
rights or remedies provided by law.
<PAGE>   12
                                                                              12

                  18. Section Headings. The Section headings used in this
Agreement are for convenience of reference only and are not to affect the
construction hereof or be taken into consideration in the interpretation hereof.

                  19. Successors and Assigns. This Agreement shall be binding
upon the successors and assigns of each Pledgor and shall inure to the benefit
of the Administrative Agent and the Lenders and their successors and assigns.

                  20. GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY, AND
CONSTRUED AND INTERPRETED IN ACCORDANCE WITH, THE LAW OF THE STATE OF NEW YORK.


<PAGE>   13
                                                                              13

                  IN WITNESS WHEREOF, the undersigned has caused this Agreement
to be duly executed and delivered as of the date first above written.


                                       ERIE SCIENTIFIC COMPANY
                                       NALGE NUNC INTERNATIONAL CORPORATION
                                       SYBRON DENTAL SPECIALTIES, INC.
                                       ORMCO CORPORATION
                                       SAC/KERR, INC.
                                       KERR CORPORATION
                                       SAC/COMMONWEALTH, INC.
                                       SYBRON COMMONWEALTH HOLDINGS, INC.
                                       NUNC U.K. LIMITED
                                       SYBRON LABORATORY PRODUCTS CORPORATION
                                       LRS ACQUISITION CORP.
                                       DIAGNOSTIC REAGENTS, INC.
                                       CASCO-NERL DIAGNOSTICS CORPORATION
                                       BARNSTEAD THERMOLYNE CORPORATION


                                       -----------------------------------------
                                       By: John Buono
                                           Title:  Assistant Treasurer


<PAGE>   14

                                                                      SCHEDULE 1
                                                             TO PLEDGE AGREEMENT



                          DESCRIPTION OF PLEDGED STOCK
                                [NAME OF PLEDGOR]


<TABLE>
<CAPTION>
-----------------      -------------------   ----------------------------   ---------------          ------------------
                                                                                                       Total No. of
                                                Stock Certificate No.        No. of Shares           Shares Outstanding
    Issuer                Class of Stock                                         Pledged
<S>                    <C>                   <C>                            <C>                      <C>
</TABLE>





                                   [Attached]


<PAGE>   15




                                                                      SCHEDULE 2
                                                             TO PLEDGE AGREEMENT



                                  PLEDGED NOTES
                                [NAME OF PLEDGOR]




<TABLE>
<CAPTION>
                                                           Original
                                 Date of                   Principal
       Obligor                    Note                      Amount
       -------                 ----------                 ----------
<S>                            <C>                       <C>
                                                         $
                                                          ----------
</TABLE>

<PAGE>   16

                           ACKNOWLEDGEMENT AND CONSENT


         Each of the undersigned is an Issuer referred to in the foregoing
Pledge Agreement, and each of the undersigned hereby acknowledges receipt of a
copy of the Pledge Agreement, dated as of July   , 1999, made by the Pledgors
(as defined therein) in favor of The Chase Manhattan Bank, as Administrative
Agent (as amended, supplemented or otherwise modified from time to time, the
"Pledge Agreement"). The undersigned agree for the benefit of the Administrative
Agent and the Lenders as follows:

         1. The undersigned will be bound by the terms of the Pledge Agreement
and will comply with such terms insofar as such terms are applicable to the
undersigned.

         2. The undersigned will notify the Administrative Agent promptly in
writing of the occurrence of any of the events described in paragraph 5.(a) of
the Pledge Agreement.

         3. The terms of paragraph 9.(c) of the Pledge Agreement shall apply to
it, mutatis mutandis, with respect to all actions that may be required of it
under or pursuant to or arising out of Section 9 of the Pledge Agreement.

                                       BARNSTEAD THERMOLYNE CORPORATION
                                       ERIE SCIENTIFIC COMPANY
                                       ERIE ELECTROVERRE S.A.
                                       ERIE SCIENTIFIC COMPANY OF PUERTO RICO
                                       ERIE-WATALA GLASS COMPANY LIMITED
                                       ERIE SCIENTIFIC HUNGARY KFT.
                                       EVER READY THERMOMETER CO., INC.
                                       RICHARD-ALLAN SCIENTIFIC COMPANY
                                       CASCO-NERL DIAGNOSTICS CORPORATION
                                       THE NAUGATUCK GLASS COMPANY
                                       NALGE NUNC INTERNATIONAL CORPORATION
                                       ORMCO CORPORATION
                                       ORMCO (EUROPE) A.G.
                                       ORMEX, S.A. DE C.V.
                                       ORMCO PTY. LTD.
                                       ORMCO DE MEXICO SA de CV
                                       ALLESEE ORTHODONTIC APPLIANCES, INC.
                                       S.D.S. DE MEXICO, SA de CV
                                       SAC/KERR, INC.
                                       KERR CORPORATION
                                       KERR AUSTRALIA PTY. LIMITED
                                       KERR ITALIA S.P.A.
                                       KERR (EUROPE) A.G.
                                       METREX RESEARCH CORPORATION
                                       BELLE DE ST. CLAIRE, INC.
                                       SYBRON DEUTSCHLAND GMBH



<PAGE>   17


                                       SAC/COMMONWEALTH, INC.
                                       SYBRON COMMONWEALTH HOLDINGS, INC.
                                       SYBRON CANADA LIMITED
                                       SYBRON U.K. LIMITED
                                       SYBRON HOLDINGS A/S
                                       REMEL INC.
                                       SYBRON DENTAL SPECIALTIES JAPAN, INC.
                                       DIAGNOSTIC REAGENTS, INC.
                                       ALEXON-TREND, INC.
                                       CHASE SCIENTIFIC GLASS, INC.
                                       OWL SEPARATION SYSTEMS INC.
                                       NALGE NUNC INTERNATIONAL K.K.
                                       SUMMIT BIOTECHNOLOGY, INC.
                                       SOCODENT S.A.
                                       SYBRON HOLDINGS A/S
                                       MAQUILADORA ACI - MEX S.A. de C.V.
                                       APPLIED BIOTECH, INC.
                                       SAMCO SCIENTIFIC CORPORATION
                                       MOLECULAR BIOPRODUCTS, INC.
                                       MICROGENICS HOLDING CORPORATION
                                       LAB-LINE INSTRUMENTS, INC.
                                       LRS ACQUISITION CORP.
                                       ORMCO B.V.



                                       ----------------------------------------
                                       By:  John Buono
                                            Title:  Assistant Treasurer or
                                                    Authorized Agent



                                       Address for Notices:

                                       c/o Sybron International Corporation
                                       411 East Wisconsin Avenue, 24th Floor
                                       Milwaukee, Wisconsin  53202
                                       Fax:  (414) 274-6561