Exhibit 4.19


                                     $75,000,000
                                   DEMAND DEBENTURE

                                 64804 MANITOBA LTD.
                                  150 Beghin Avenue
                                  Winnipeg, Manitoba
                                       R2J 3W2
                                           
1.  PROMISE TO PAY

         The above-named corporation (the "CORPORATION") for value received
promises to pay to The Bank of Nova Scotia (the "CANADIAN AGENT") at its offices
at 44 King Street West, Toronto, Ontario, M5H 1Hl on demand all amounts now or
hereafter owing by the Corporation to the Canadian Secured Parties (as defined
below) or any of them, up to the maximum principal amount of $75,000,000 in
lawful money of Canada, and interest at the rate of 25% per annum, calculated
daily and payable on demand, both before and after maturity and default, with
interest on overdue interest at the same rate.  

         This Debenture is granted to the Canadian Agent on its own behalf and
as agent for the following:

    (a)  the Canadian Lenders and the Canadian Issuers, each as defined in the
         credit agreement dated as of 30 June 1997 (as amended, supplemented,
         restated and replaced from time to time, the "CREDIT AGREEMENT")
         between Vita Health Company (1985) Ltd. (the "Canadian Borrower"), The
         Bank of Nova Scotia as Canadian Agent, the Canadian Lenders and
         certain other parties;

    (b)  each counterparty to a Rate Protection Agreement (as defined in the
         Credit Agreement) entered into by the Corporation or the Canadian
         Borrower that is (or at the time the Rate Protection Agreement was
         entered into, was) a Canadian Lender or an Affiliate (as defined in
         the Credit Agreement) of a Canadian Lender; and

    (c)  their respective successors, permitted transferees and permitted
         assigns.

         The Canadian Agent and the persons listed above are collectively
referred to in this Debenture as the "CANADIAN SECURED PARTIES".  The
Corporation and the Canadian Borrower are collectively referred to in this
Debenture as the "CANADIAN OBLIGORS".

2.  OBLIGATIONS SECURED

         This Debenture secures payment and performance by the Canadian
Obligors or any of them to the Canadian Secured Parties or any of them of all
debts, liabilities and obligations, present or future, direct or indirect,
absolute or contingent, matured or not, choate or inchoate, in any currency, at
any time owing by the Canadian Obligors or any of them to the Canadian Secured
Parties or any of them under or in connection with the Credit 




Documents (as defined below) or remaining unpaid by the Canadian Obligors or 
any of them to the Canadian Secured Parties or any of them under or in 
connection with the Credit Documents, whether arising from dealings between 
the Canadian Secured Parties or any of them and the Canadian Obligors or any 
of them or from any other dealings or proceedings by which the Canadian 
Secured Parties or any of them may be or become in any manner whatever a 
creditor of the Canadian Obligors or any of them under or in connection with 
the Credit Documents, and wherever incurred, and whether incurred by the 
Canadian Obligors or any of them alone or with another or others and whether 
as principal or surety (including but not limited to any guarantee by the 
Canadian Obligors or any of them of obligations of other persons to the 
Canadian Secured Parties or any of them), and all interest, commissions, 
legal and other costs, charges and expenses (collectively, the "OBLIGATIONS 
SECURED").  The "CREDIT DOCUMENTS" include the Credit Agreement, all 
promissory notes of the Corporation delivered under or in connection with the 
Credit Agreement, as the promissory notes are amended, endorsed or otherwise 
modified from time to time, standby or documentary letters of credit issued 
for the account of the Corporation pursuant to the Credit Agreement from time 
to time, any guarantee by the Corporation required by the Credit Agreement, 
any Rate Protection Agreement to which the Canadian Obligors or any of them 
is a party and any other Loan Document (as defined in the Credit Agreement) 
to which the Canadian Obligors or any of them is a party.

3.  GRANT OF SECURITY

         As security for the payment of the obligations secured, the
Corporation charges as and by way of a floating charge to and in favour of the
Canadian Agent, and grants to the Canadian Agent a security interest in, all of
the present and after-acquired property, undertaking and assets of the
Corporation for the time being, both real and personal, movable and immovable,
of whatsoever nature and kind now owned or hereafter acquired, including its
goodwill and uncalled capital, (all property, undertaking and assets subject to
the said mortgages, charges and security interests being collectively referred
to as the "MORTGAGED PROPERTY").

4.  LEASES

         The charge of the mortgaged property contained in section 3 shall not
extend or apply to the last day of the term of any lease or any agreement
therefor now held or hereafter acquired by the Corporation, but should the said
charge become enforceable the Corporation shall thereafter stand possessed of
such last day and shall hold it in trust to assign the same to any person
acquiring such term or the part thereof charged in the course of any enforcement
of the said charge or any realization of the subject matter thereof.

5.  CONTRACTS, RIGHTS OR LICENCES

         In this section 5, "RESTRICTED ASSET" shall mean any contract, right
or licence of the Corporation, including any right of the Corporation as a
security holder, shareholder or holder of a partnership interest, if pursuant to
the terms of such contract, right or licence, 




or pursuant to the terms of any agreement affecting such contract, right or 
licence, the contract, right or licence would automatically terminate if it 
was part of the mortgaged property, or would be terminable at the option of 
the other party thereto or of the grantor thereof, or would be subject to 
disposition, alteration or amendment at the option of another party including 
another security holder, shareholder or holder of a partnership interest. The 
charge of the mortgaged property contained in section 3 shall not extend or 
apply to any Restricted Asset.  Should the charge become enforceable, the 
Corporation shall thereafter stand possessed of each Restricted Asset and 
shall hold it in trust to assign the same or dispose of the same to any 
person as requested by the Canadian Agent.  In order that the full value of 
all such Restricted Assets may be realized for the benefit of the Canadian 
Secured Parties, the Corporation shall at its expense and at the request of 
the Canadian Agent from time to time, take all such action and do or cause to 
be done all such things as shall, in the opinion of the Canadian Agent acting 
reasonably (with advice of counsel as the Canadian Agent considers 
appropriate), be necessary or proper in order that all such Restricted Assets 
shall enure to the benefit of the Canadian Agent.

6.  NEGATIVE PLEDGE

         The Corporation covenants that it shall not, without the consent in
writing of the Canadian Agent, create, assume, incur or permit the existence of
any mortgage, hypothec, charge, lien or other encumbrance upon the mortgaged
property or any part thereof, other than as may be permitted by the Credit
Agreement.

7.  INSPECTION OF MORTGAGED PROPERTY

         Until an event of default occurs, the Corporation may use the
mortgaged property in any lawful manner not inconsistent with this Debenture,
but the Canadian Agent shall have the right at reasonable times and intervals to
verify the existence and state of the mortgaged property in any manner the
Canadian Agent may consider appropriate and the Corporation agrees to furnish
all assistance and information and to perform all such acts as the Canadian
Agent may reasonably request in connection therewith, and for such purpose shall
permit the Canadian Agent or its agents access at reasonable times and intervals
to all places where any mortgaged property may be located and to all premises
occupied by the Corporation to examine and inspect the mortgaged property and
related records and documents.

8.  EVENTS OF DEFAULT

         The obligations secured shall immediately become payable and the
security constituted by this Debenture shall immediately become enforceable in
each of the following events:

    (a)  if any Canadian Obligor defaults in payment of any of the obligations
         secured and the default continues beyond any applicable grace period;




    (b)  if the Corporation defaults in performance of any covenant or
         condition of this Debenture and the default continues beyond any
         applicable grace period; or

    (c)  if an event of default occurs and is continuing pursuant to the Credit
         Agreement.

9.  WAIVER OF DEFAULT

         The Canadian Agent may by notice to the Corporation waive any default
of any Canadian Obligor on such terms and conditions as the Canadian Agent may
determine, but no such waiver shall be taken to affect any subsequent default or
the rights resulting therefrom.

10. REMEDIES

         Whenever the security constituted by this Debenture becomes
enforceable and so long as it remains enforceable, the Canadian Agent may:

    (a)  immediately take possession of the mortgaged property and, whether or
         not the Canadian Agent has done so, may sell, lease or otherwise
         dispose thereof either as a whole or in separate parcels, at public
         auction, by public tender or by private sale, with or without notice,
         either for cash or upon credit, and upon such terms and conditions as
         the Canadian Agent may determine; and the Canadian Agent may execute
         and deliver to any purchaser of the mortgaged property or any part
         thereof good and sufficient deeds and documents for the same, the
         Canadian Agent being irrevocably constituted the attorney of the
         Corporation for the purpose of making any such sale, lease or other
         disposition and executing such deeds and documents;

    (b)  by instrument in writing appoint any person to be a receiver (which
         term shall include a receiver and manager) of the mortgaged property
         or of any part thereof and may remove any receiver so appointed and
         appoint another in his stead; and any such receiver so appointed shall
         have power:(i) to take possession of the mortgaged property or any
         part thereof,(ii) to carry on all or any part of the business of the
         Corporation relating to the mortgaged property,(iii) to borrow money
         on the security of the mortgaged property in priority to the Debenture
         for the purpose of the maintenance, preservation or protection of the
         mortgaged property or any part thereof or for carrying on all or any
         part of the business of the Corporation relating to the mortgaged
         property, and (iv) to sell, lease or otherwise dispose of the whole or
         any part of the mortgaged property, at public auction, by public
         tender or by private sale, with or without notice, either for cash or
         upon credit, at such time and upon such terms and conditions as the
         receiver may determine; provided that any such receiver shall be
         deemed the agent of the Corporation and the Canadian 




         Secured Parties shall not be in any way responsible for any misconduct 
         or negligence of any such receiver; and

    (c)  exercise any of the other rights to which the Canadian Agent is
         entitled as holder of this Debenture, including the right to take
         proceedings in any court of competent jurisdiction for the appointment
         of a receiver and manager, for the sale of the mortgaged property or
         any part thereof or for foreclosure, and the right to take any other
         action, suit, remedy or proceeding authorized or permitted under the
         Debenture or by law or by equity in order to enforce the security
         constituted by this Debenture.

         In the exercise of their rights, powers and authorities under this
Debenture, the Canadian Agent and any receiver or receiver and manager appointed
by the Canadian Agent shall be the agent of the Corporation, and the Canadian
Agent shall not be in any way responsible for any misconduct or negligence of
any such receiver or receiver and manager.  The Canadian Agent or any agent or
representative thereof, may become purchasers at any public sale of the
mortgaged property, whether made under a power of sale provided for in this Deed
or pursuant to judicial proceedings.

11. TAXES AND OTHER CHARGES

         The Corporation shall pay all rents, taxes, rates, levies, assessments
and government fees or dues levied, assessed or imposed in respect of the
mortgaged property or any part thereof (collectively "TAXES") as and when the
same shall become due and payable and shall pay all charges, liens and other
encumbrances on the mortgaged property (collectively "CHARGES") as and when the
same shall become due and payable.  If the Corporation does not pay any Taxes or
Charges as and when the same shall become due and payable, the Canadian Agent
may, at its option, elect to pay any such amounts and charge to the Corporation
all amounts so paid as additional amounts secured under this Deed, together with
interest thereon from the date of payment by the Canadian Agent of any such
amounts at the highest rate applicable to Canadian dollar advances pursuant to
the Credit Agreement.  The Corporation may contest in good faith the payment of
any Taxes or Charges provided that the Corporation is proceeding diligently and
in good faith and in the best possible manner to contest the claim, the
Corporation's interest in the mortgaged property cannot be forfeited, sold or
affected in any other way while contesting the claim, the Corporation keeps the
Canadian Agent fully informed of the proceedings, the Corporation has made
arrangements satisfactory to the Canadian Agent acting reasonably in respect of
the payment of the contested Taxes or Charges and the Corporation pays in
accordance with section 12 any expenses incurred by the Canadian Agent in
connection with the proceedings.

12. EXPENSES

         The Corporation shall pay to the Canadian Agent upon demand the amount
of all reasonable expenses incurred in recovering any obligations secured or in
enforcing the security  constituted by this Debenture, including but not limited
to, the expenses incurred in 




connection with the repossession, holding, repairing, processing, preparing 
for disposition, and disposing of any of the mortgaged property (including 
reasonable legal and other expenses), with interest thereon from the date of 
the incurring of such expenses at the highest rate applicable to Canadian 
dollar advances pursuant to the Credit Agreement.

13. DISCHARGE

         If the Corporation pays to the Canadian Agent the obligations secured
by this Debenture or if the obligations secured by this Debenture are otherwise
paid in full and the Corporation otherwise observes and performs the terms and
conditions of this Debenture, then the Canadian Agent shall at the request and
at the expense of the Corporation cancel and discharge the mortgage and charge
of this Debenture and execute and deliver to the Corporation such deeds and
other instruments as shall be requisite therefor.  For the purposes of this
section 13 only, "obligations secured" shall not include Rate Protection
Agreements that are not entered into pursuant to the Credit Agreement.

14. NOTICES

         Unless otherwise provided in any agreement to which the Canadian Agent
and the Corporation are parties, any notice or demand required or permitted to
be given or made under this Debenture by the Canadian Agent to the Corporation
may be served personally on a director, officer or employee of the Corporation
or may be given or made by mailing the same by prepaid registered mail addressed
to the Corporation at its address as set out above and shall, unless a different
date of receipt is established by law, be conclusively deemed to have been
received by the Corporation if served personally on the day served and if given
or made by mailing by prepaid registered mail on the third business day
following the date of such mailing.

15. CONTINUING AND ADDITIONAL SECURITY

         This Debenture shall not be considered as satisfied or discharged by
any intermediate payment (as distinct from a final payment) of the whole or part
of the obligations secured but shall constitute and be a continuing security for
a current or running account and shall be in addition to and not in substitution
for any other security now or hereafter held by or for the benefit of the
Canadian Agent. The remedies of the Canadian Agent under this Debenture may be
exercised from time to time separately or in combination and are in addition to
and not in substitution for any other rights of the Canadian Agent however
created.

16. AMALGAMATIONS

         If the Corporation amalgamates with any corporation or corporations,
the obligations secured by this Debenture and the mortgage and charge created by
this Debenture shall continue and shall extend to the present and future
undertaking, property and assets of 




the amalgamated corporation, as if the amalgamated corporation had executed 
this Debenture as the Corporation.

17. TRANSFERABLE

         Subject to any restrictions on transfer contained in the Credit
Agreement or any other agreement to which the Corporation and the Canadian Agent
are parties, the obligations secured by this Debenture shall be paid and this
Debenture shall be transferable without regard to any set-off or counter-claim
between the Corporation and the Canadian Agent.

18. EFFECT OF HEADINGS

         The headings and marginal notes of the sections in this Deed are
inserted for convenience of reference only and shall not affect the
interpretation of this Debenture.

19. LAW GOVERNING

         This Debenture shall be governed in all respects by the law of the
Province of Manitoba and the federal laws of Canada applicable therein.

20. FURTHER COVENANTS

         The Corporation shall not:

    (a)  change its name without providing the Canadian Agent with prior 30
         days written notice thereof and promptly taking other steps, if any,
         as the Canadian Secured Parties reasonably request to permit the
         Canadian Agent to perfect the Security with respect to the change in
         name;

    (b)  permit its chief executive office or chief place of business to be
         located out of the Province of Manitoba without providing the Canadian
         Agent with 30 days prior written notice thereof and promptly taking
         other steps, if any, as the Canadian Secured Parties reasonably
         request to permit the Canadian Agent to perfect the security with
         respect to the change in location;

    (c)  permit any of its tangible personal property (other than (i) inventory
         in transit (ii) goods of a type normally used in more than one
         jurisdiction which are equipment or inventory leased or held for lease
         by the Corporation to others or (iii) tangible personal property of a
         value which is not material in relation to the obligations secured
         which is temporarily located out of Manitoba) to be located out of
         Manitoba without providing the Canadian Agent with 30 days prior
         written notice thereof and promptly taking other steps, if any, as the
         Canadian Secured Parties reasonably request to permit the Canadian
         Agent to perfect the security with respect to the change in location.




         The Corporation shall, forthwith on demand, deliver to the Canadian
Agent possession of all "instruments," "securities," "letters of credit,"
"advices of credit" and "negotiable documents of title" as those terms are
defined or used in the Personal Property Security Act (Manitoba) as amended from
time to time.  The Corporation shall also, forthwith on demand, deliver to the
Canadian Agent all such security agreements, mortgages and other documents as
may be reasonably required to provide the Canadian Agent with a fixed and
specific mortgage and charge and a security interest in all patents, trademarks
and other intellectual property in which the Corporation now or hereafter holds
an interest and to provide the Canadian Agent with a fixed and specific mortgage
and charge and a security interest in any or all real and immovable property
(including leaseholds), equipment, machinery, vehicles and other tangible
personal property hereafter acquired by the Corporation.

         The Corporation represents and warrants that as of the date of this
Debenture, all of its tangible property, other than inventory in transit, is
located in the Province of Manitoba and all of its accounts receivable are
billed from, and payment is customarily received in, the same place.

         IN WITNESS WHEREOF this Debenture has been signed by its duly
authorized officer as of 30 June 1997.

                                    64804 MANITOBA LTD.



                                    By: /s/ William B. Towne                 c/s
                                       --------------------------------------
                                       Name:  William B. Towne
                                       Title: Treasurer