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                                                                   Exhibit 10.41

                            THIRD AMENDMENT TO LEASE

         THIS THIRD AMENDMENT TO LEASE (hereinafter referred to as the "Third
Amendment"), dated September 16, 1999 is between OTR, an Ohio general
partnership acting as the duly authorized nominee of the board of The State
Teachers Retirement System of Ohio (hereinafter referred to as "Lessor"), whose
address is 275 East Broad Street, Columbus, Ohio 43215, and NORTHFIELD
LABORATORIES, INC., a Delaware corporation (hereinafter referred to as
"Lessee").


                              W I T N E S S E T H:


         A.  Lessor and Lessee have entered into a certain Lease dated June 8,
1989 which Lease was amended by First Amendment to Lease dated November 24, 1992
(hereinafter referred to as the "First Amendment to Lease") and by Second
Amendment to Lease dated May 5, 1998 (hereinafter referred to as the "Second
Amendment to Lease" and said Lease as amended by the First Amendment to Lease
and the Second Amendment to Lease is hereinafter referred to as the "Lease"),
with respect to certain premises as therein described (hereinafter referred to
as the "Original Premises") located in the Property (hereinafter referred to as
"Property") known and described as 1200 Business Center Drive, Suite 200, Mt.
Prospect, Illinois 60056.

         B.  Lessor and Lessee now desire to expand the Original Premises by
adding certain additional premises which the parties hereto acknowledge contain
an area of thirty-five thousand four hundred and twenty-four (35,424) square
feet and which are depicted on Exhibit "A" attached hereto and by this reference
incorporated herein (hereinafter referred to as the "Expansion Space"). The
parties hereto acknowledge that upon the addition of the Expansion Premises to
the Original Premises the total area demised to Lessee shall increase to
fifty-five thousand eight hundred and twenty-four (55,824) square feet and
Lessee's Pro Rata Share shall increase to fifty-two and 66/100 percent (52.66%).

         NOW, THEREFORE, in consideration of the mutual promises, covenants and
conditions contained in this Agreement and the foregoing recitals which are, by
this reference, incorporated herein, the parties agree as follows:

         1.  DEMISE. The Lessor hereby demises the Expansion Premises to Lessee
for a term commencing on September 15, 1999 (hereinafter referred to as the "New
Start Date") whereupon all references in the Lease to the Premises shall be
deemed to refer to the Original Premises and the Expansion Premises. The Lessee
hereby accepts the Expansion Premises in their present "as-is" condition. The
Lessee's taking possession of the Expansion Premises shall be deemed to the
Lessee's acceptance of the Expansion Premises in the order and condition as then
exists. No promise of the Lessor to alter, remodel, decorate, clean or improve
the Expansion Premises of the Property and no representation respecting the
condition of the Expansion Premises or the Property have been made by the Lessor
or by any agent or representative of the Lessor to the Lessee. Any improvement,
alteration, addition or installation to the Expansion Premises shall be made
only in compliance with the terms of Article VIII of the Lease. Notwithstanding
the foregoing, Lessee shall not be required to post a performance bond.
Furthermore, Lessor approves (xxxxxxxx xxxxxxxxxx xxxxxxxxxxxx xxxxxx) as the
contractor and (xxxxxxxx xxxxxxxxxx xxxxxxxxxxxx xxxxxx) subcontractors for the
improvements, alterations, additions or installations to the Expansion Premises
and approves the space plan and plans and specifications attached hereto and
incorporated herein as Exhibit "B" (the "Plans"). Lessor reserves the right to
notify Lessee, at or



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prior to the termination of the Lease, that Lessee must remove the improvements
installed by Lessee under the terms of this paragraph, at Lessee's sold cost and
expense and repair or restore any damage caused by the installation or such
removal. Lessor acknowledges that the Plans do not show layouts for machinery
and piping because of the confidential nature of Lessee's trade secrets. Any
charges for Lessor's engineer shall be limited to those charges for inspection
and engineering time as set forth in Article VIII for structural items, building
systems and other items shown on the Plans. Any inspections of construction
operations performed by Lessor or Lessor's agents shall be reasonable and Lessor
and Lessor's agents agree to not disclose to any independent third party the
nature of such construction, unless required by law, court order or in relation
to any litigation arising out of this Lease or the improvements. Effective on
the New Start Date the Lessee's Pro Rata Share shall increase to be fifty-two
and 66/100 percent (52.66%) of the Excess Real Estate Taxes for the applicable
Lease Year, and the term Lessee's Pro Rata Share of Excess Expenses shall mean
fifty-two and 66/100 percent (52.66%) of the Excess Expenses for the applicable
Lease Year.

         2.  TERM. The terms of the Lease is hereby extended for a period of one
(1) month and shall terminate on August 30, 2004 ("Term").

         3.  BASE RENT.

             (a)  Commencing on the New Start Date and terminating on June 30,
2002 the Annual Base Rent shall be the sum of TWO HUNDRED SIXTY-SEVEN THOUSAND
NINE HUNDRED FIFTY-FIVE AND 20/100 ($267,955.20) DOLLARS which shall be payable
monthly, in advance on the first day of each and every month during such
period, in equal monthly installments in the amount of TWENTY-TWO THOUSAND THREE
HUNDRED TWENTY-NINE AND 60/100 ($22,329.60) DOLLARS. The Annual Base Rent is
comprised of Annual Base Rent for the Original Premises in the amount of NINETY
SEVEN THOUSAND NINE HUNDRED TWENTY AND 00/100 ($97,920.00) DOLLARS and Annual
Base Rent for the Expansion Space in the amount of ONE HUNDRED SEVENTY THOUSAND
THIRTY-FIVE AND 20/100 ($170,035.20) DOLLARS.

             (b)  The Annual Base Rent for the period commencing on July 1, 2002
and terminating on August 30, 2004 shall be the sum of TWO HUNDRED EIGHTY-FOUR
THOUSAND SEVEN HUNDRED TWO AND 40/100 ($284,702.40) DOLLARS which shall be
payable monthly, in advance on the first day of each and every month during such
period, in equal monthly installments in the amount of TWENTY THREE THOUSAND
SEVEN HUNDRED TWENTY FIVE AND 20/100 ($23,725.20) DOLLARS.

         If the New Start Date is a date other than the first day of a calendar
month the monthly rent attributable to the Expansion Space for the remainder of
the first calendar month shall be prorated based upon the number of days in such
month. If the Term expires on a day other than the last day of a calendar month,
the rent for such month shall be prorated based upon the ratio that the number
of days of the Term in such month bears to the total number of days in such
month.

             4.  COMMERCIAL. The words "small scale" appearing in the eighth
line of the second paragraph of the Lease and in Article VI of the Lease shall
be deleted and replaced with the word "commercial".

             5.   MORTGAGE. Lessor represents that as of the date of this Third
Amendment, there is no mortgage encumbering the Property.



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             6.   DAMAGE BY FIRE OR OTHER CASUALTY. The number one hundred
twenty (120) appearing in line 4 and line 8 of the first paragraph, line 4 and
line 7 of the second paragraph, and line 4 of the third paragraph of Article XII
is hereby deleted and replaced with the number three hundred sixty-five (365).

             7.   NOTICES. Paragraph C. of Article XVII is hereby deleted and
the following Paragraph C is hereby inserted in place thereof:

             C.   All notices, demands, requests, consents and approvals that
             may or are required to be given by either party to the other shall
             be in writing and shall be deemed given when sent by United States
             certified or registered mail, postage prepaid, or by overnight
             courier (a) if for Lessor addressed to Lessee at Suite 1000, 1560
             Sherman Avenue, Evanston, Illinois 60201, Attention: Jack Kogut
             with a copy to Sidney Saltz, Jenner & Block, One IBM Plaza,
             Chicago, Illinois 60601, or at such other place as Lessee may from
             time to time designate by notice to Lessor, or (b) if for Lessor,
             addressed to Insignia/ESG, Inc., 8420 W. Bryn Mawr, Suite 900,
             Chicago, Illinois 60631 with a copy to Lessor, c/o OTR, 275 East
             Broad Street, Columbus, Ohio 43215, Attention: Real Estate Manager,
             or at such other place as Lessor may from time to time designate by
             notice to Lessee. All consents and approvals provided for herein
             must be in writing to be valid. Notice shall be deemed to have been
             given if addressed and sent as above provided on the date of
             delivery or, if delivery is refused, on the date of such attempted
             delivery.

             8.   NOTICE UPON ENTRY. After the phrase "Lessee's security and
cleanliness" in line 12 of Article XX in the Rider to Lease, the phrase "and
confidentiality" is hereby added.

             9.   PARKING RIGHTS. The numbers forty-three (43) and twenty-two
(22) appearing in the third paragraph of Article XXI are hereby deleted and the
numbers one hundred and eighteen (118) and sixty-two (62), respectively, are
inserted in place thereof.

             10.  OPTION TO RENEW. Lessee shall have the option to renew the
Lease for two (2) successive five (5) year terms, commencing on the expiration
of the Term as set forth in Paragraph 2 hereof, in accordance with the terms and
conditions of Article XXIV of the Lease.

             11.  ASSIGNMENT AND SUBLETTING. The phrase "provided, however, such
parent, subsidiary or affiliate has a financial net worth, as evidenced by
financial statements prepared by a certified public accountant in excess of the
total financial net worth of all parties obligated under the terms and
conditions constituting the obligations of Lessee herein" beginning in line 10
of Article XXX in the Rider to Lease is hereby deleted.

             12.  WATER USE. Article XXXI of the Lease is hereby amended to
provide that Lessee agrees it shall cause the water service to the Premises to
be separately metered and Lessee shall be responsible for all costs and expenses
arising in connection with said installation of facilities necessary for the
separate metering including without limitation all increased sewer charges
directly attributable to Lessee's water use at the Premises. Pursuant to Article
XXXI of the Lease, the category of water service and sewer charges is hereby
excluded from the computation of Operating Expenses.



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             13.  BROKERAGE COMMISSION. Except for any broker, agent or other
person named below, Lessor and Lessee represent and warrant each to the other
that each has dealt with no broker, agent or other person in connection with
this transaction and that no broker, agent or other person brought about this
transaction. Lessor hereby agrees to pay Insignia/ESG, Inc. ("Agent") a leasing
commission as set forth in that certain Management Agreement between Lessor and
Agent, from which Agent has agreed to pay a "co-op" leasing commission to
Cushman & Wakefield of Illinois, Inc. ("Co-op Broker"). Lessee agrees to
indemnify and hold Lessor harmless from and against any claims by any other
broker, agent or other person (including, without limitation, Co-op Broker)
claiming a commission to other form of compensation by virtue of having dealt
with Lessee with regard to this leasing transaction. The provisions of this
Paragraph 6 shall survive the termination of the Lease as amended by this Third
Amendment.

             14.  NON-CONFLICTING LEASE TERMS RATIFIED. Except as modified
herein, the terms, covenants and conditions of the Lease are ratified and
confirmed and the parties shall be bound by, and shall have the benefits of, all
the terms, covenants and conditions of the Lease.

             15.  THIRD AMENDMENT CONTROLS. If any terms, covenants or
conditions of this Third Amendment conflict with the terms, covenants and
conditions of the Lease, then the terms and conditions of this Third Amendment
shall control.

             16.  EXCULPATION. This Third Amendment to Lease is executed by
certain employees of The State Teachers Retirement System of Ohio, not
individually, but solely on behalf of Lessor, the authorized nominee and agent
for The State Teachers Retirement Board of Ohio ("STRBO"). In consideration for
entering into this Third Amendment to Lease, Lessee hereby waives any rights to
bring a cause of action against the individuals executing this Lease on behalf
of Lessor (except for any cause of action based upon lack of authority or
fraud), and all persons dealing with Lessor must look solely to the Property for
the enforcement of any claim against Lessor, and the obligations under the
Lease, as amended hereby, are not binding upon, nor shall resort be had to the
private property of any of, the trustees, officers, directors, employees or
agents of STRBO.







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         IN WITNESS WHEREFORE, the parties to this Third Amendment to Lease
Agreement have extended the same on the day and year written above.


                                    LESSOR:

                                    OTR, an Ohio General Partnership


                                    By:
                                       ------------------------------------

                                       Its:
                                            -------------------------------


                                     LESSEE:

                                     NORTHFIELD LABORATORIES INC.,
                                     a Delaware Corporation


                                     By:
                                       ------------------------------------
                                       Its:
                                            -------------------------------