LEASE
                                      -----

                                    ARTICLE I
                               ------------------

                          Fundamental Lease Provisions
                          ----------------------------

              1.1 Reference Subjects. Each reference in this Lease to any of the
following  subjects shall be construed to incorporate the information stated for
that subject in this Section.

DATE:                             February 5, 1997

PREMISES:                         Portions    of    the    Building     totaling
                                  approximately   43,268  rentable  square  feet
                                  described on Appendix Al attached, (consisting
                                  of  approximately  22,753 rentable square feet
                                  on  the  200  level  of  the  East  Wing  (the
                                  "Expansion  Premises"),   approximately  9,356
                                  rentable  square  feet on the 100 level of the
                                  East Wing,  currently  leased to J. Howard and
                                  scheduled   to  be   delivered  to  Tenant  as
                                  described   in   Section   2.3  (the   "Second
                                  Expansion   Premises"),   approximately  1,000
                                  square feet of storage  space on the 100 level
                                  in the parking  garage (the  "Storage  Space")
                                  and approximately  10,159 rentable square feet
                                  on  the  300  Level  of  the  East  Wing  (the
                                  "Existing  Premises")).  The  areas  set forth
                                  herein  are  determined   under  the  Standard
                                  Method  of  Floor   Measurement   for   Office
                                  Buildings  published  by The Real Estate Board
                                  of New York, Inc.

BUILDING:                         The  Building   complex   known  as  Ledgemont
                                  Development   Center  and  consisting  of  the
                                  "Richards  House,"  "Building  B," "B  Annex,"
                                  "Building C," "East Wing," the parking  garage
                                  and other appurtenances thereto located at 128
                                  Spring Street, Lexington,  Massachusetts.  The
                                  Building  consists  of  approximately  182,317
                                  rentable  square feet,  of which the East Wing
                                  consists  of  approximately   50,883  rentable
                                  square feet.









LANDLORD:                         LEDGEMONT  REALTY  TRUST u/d/t dated  December
                                  12, 1984

ORIGINAL ADDRESS                  c/o The Beal Companies
    OF LANDLORD:                  177 Milk Street
                                  Boston, Massachusetts   02109

LANDLORD'S MANAGING               The Beal Companies
     AGENT:                       177 Milk Street
                                  Boston, Massachusetts   02109

TENANT:                           Interneuron Pharmaceuticals,  Inc., a Delaware
                                  corporation

ORIGINAL ADDRESS                  99 Hayden Avenue
      OF TENANT:                  Lexington, Massachusetts   02173

INITIAL TERM:                     Five (5) years and one and one-half months

COMMENCEMENT DATE:                March 1, 1997, or, if later, the date on which
                                  both (i) Landlord has delivered  possession of
                                  the  Expansion  Premises  to  Tenant  and (ii)
                                  Landlord  has given  Tenant  14 days'  advance
                                  notice  of when  possession  of the  Expansion
                                  Premises will be delivered.

RENT COMMENCEMENT DATE:           One and one-half months after the Commencement
                                  Date, estimated to be April 15, 1997.

ENDING DATE:                      April 14,  2002,  subject to  extension as set
                                  forth herein



                                      -2-





ANNUAL FIXED RENT--
   INITIAL TERM:
<TABLE>
<CAPTION>

                                                       Commencement Date to Delivery of        Delivery of Second
                                                           Second Expansion Premises         Expansion Premises to
                                                                                                   3/31/2002
<S>                                                   <C>                                  <C>
----------------------------------------------------- ------------------------------------ ---------------------------
----------------------------------------------------- ------------------------------------ ---------------------------
Rent Per Square Foot of Existing Premises and         $17.00                               $17.00
Expansion Premises
----------------------------------------------------- ------------------------------------ ---------------------------
----------------------------------------------------- ------------------------------------ ---------------------------
                        (1)                           $559,504.00                          $559,504.00
 Rent For Existing Premises and Expansion Premises
----------------------------------------------------- ------------------------------------ ---------------------------
----------------------------------------------------- ------------------------------------ ---------------------------
Rent Per Square Foot of Storage Space                 $6.00                                $6.00
----------------------------------------------------- ------------------------------------ ---------------------------
----------------------------------------------------- ------------------------------------ ---------------------------

----------------------------------------------------- ------------------------------------ ---------------------------
----------------------------------------------------- ------------------------------------ ---------------------------
                        (2)                           $6,000.00                            $6,000.00
               Rent For Storage Space
----------------------------------------------------- ------------------------------------ ---------------------------
----------------------------------------------------- ------------------------------------ ---------------------------
Rent Per Square Foot of Second Expansion Premises                                          $14.00
----------------------------------------------------- ------------------------------------ ---------------------------
----------------------------------------------------- ------------------------------------ ---------------------------
                        (3)                                                                $130,984.00
         Rent for Second Expansion Premises
----------------------------------------------------- ------------------------------------ ---------------------------
----------------------------------------------------- ------------------------------------ ---------------------------
                      (1+2+3)                         $565,504.00                          $696,488.00
                     TOTAL RENT

</TABLE>



EXTENSION TERM:                           Five (5) Lease years

ANNUAL FIXED RENT --                      95% of Fair Market Rent as provided in
    EXTENSION TERM:                       Section 4.1.2, but never less than the
                                          Annual Base  Rent  payable  during the
                                          year    immediately   preceding    the
                                          beginning of the Extension Term.

MINIMUM NET WORTH:                        N/A

SECURITY DEPOSIT:                         None




                                      -3-





TENANT IMPROVEMENT
ALLOWANCE:                               $392,000

PARKING SPACES:                          Ninety (90) spaces  until  delivery of
                                         the Second Expansion  Premises and One
                                         Hundred Twenty (120) spaces thereafter

TENANT'S OPERATING                       64.7%  until  delivery of  the  Second 
PERCENTAGE SHARE:                        Expansion Premises and 83.1% thereafter

TENANT'S TAX PERCENTAGE:                 18.5%  until  delivery  of  the  Second
SHARE                                    Expansion Premises and 23.8% thereafter
                                         Tenant's Operating Percentage Share and
                                         Tenant's Tax Percentage Share shall not
                                         increase  as  a  result  of  Landlord's
                                         remeasurement of the Building.

PERMITTED USES:                          Office use and all lawful uses  related
                                         thereto.

PUBLIC LIABILITY INSURANCE:              $1,500,000

BROKER:                                  Whittier Partners

APPENDICES:                              Appendix A - Premises Sketch Plan
                                         Appendix B - Special Maintenance and 
                                         Operation Requirements
                                         Appendix C - Initial Hazardous 
                                         Substances or Materials per Section 
                                         5.1.8
                                         Appendix D - Tenant Work Insurance 
                                         Schedule
                                         Appendix E - Description of W.R. Grace
                                         Space
                                         Appendix F - Cleaning Specifications



                                      -4-







                                   ARTICLE II
                                   ----------

                                Premises and Term
                                -----------------

     2.1 Premises.  Landlord  hereby  leases to Tenant, and Tenant hereby leases
from Landlord,  the Premises  identified in Section 1.1, subject to and with the
benefit of the terms,  covenants and  conditions  of this Lease,  and of rights,
agreements,  easements and restrictions of record  applicable to the property of
which the  Premises are a part,  all of which  Tenant shall  perform and observe
insofar as the same are  applicable to the Premises.  Subject to the  reasonable
rules and regulations established by Landlord, Tenant shall have the appurtenant
rights in common with others to use (a) the  exterior  walkways,  sidewalks  and
driveways  necessary  for  access to the  Premises;  and (b) up to the number of
Parking Spaces as set forth in Section 1.1 for the  non-exclusive  use of Tenant
and Tenant's employees and business invitees in areas located on-site designated
from time to time by Landlord.

     Tenant,  at its sole cost and  expense,  shall be  permitted to furnish the
existing  reception area in the East Wing (the  "Reception  Area") in the manner
consistent  with its condition as of the date hereof and to staff such Reception
Area  with a  receptionist,  so  long  as  such  receptionist  provides  general
reception  services to all tenants of the East Wing. No additional rent shall be
charged for Tenant's use of the Reception Area in accordance with the foregoing.

     Landlord  excepts and  reserves the right from time to time (a) to install,
use, maintain,  repair, replace and relocate within the Premises and other parts
of the  Building,  or  either,  pipes,  meters and other  equipment,  machinery,
apparatus and  appurtenant  fixtures;  and (b) to make additions to the Building
and  alter or  relocate  any  entranceways,  common  areas  or other  facilities
(including without limitation all access driveways,  walkways and parking areas)
serving the  Premises,  provided in either case that there shall be no reduction
in the useable  area of the  Premises  except to a de minimis  extent.  Landlord
shall restore at Landlord's  expense any part of the Premises  disturbed by such
acts of Landlord  pursuant to this  paragraph and there shall be no reduction in
the services or parking spaces available to Tenant hereunder.  In performing any
such work,  Landlord shall not  unreasonably  interfere  with Tenant's  business
operations at the Premises.

     2.2 Acceptance of Premises.  Tenant acknowledges that it currently occupies
the Existing  Premises  and is  satisfied  with the  condition  thereof.  Tenant
further acknowledges that neither Landlord nor any agent or employee of Landlord
has made any  representations  or  warranties  concerning  the  Premises,  their
condition or this Lease, except as set forth herein.




                                      -5-






     2.3 Delivery of Possession.  Landlord shall endeavor to cause possession of
the Expansion  Premises to be delivered to Tenant on or before March 1, 1997. If
there is a holding over or retention of possession of the Expansion Premises, or
any portion  thereof,  by any prior  tenant or  occupant,  or if Landlord  shall
otherwise be unable to deliver  possession of the Expansion Premises on March 1,
1997 due to causes beyond its  reasonable  control,  then Landlord  shall not be
subject to any liability for the failure or delay in giving  possession and such
failure to give  possession  shall in any other  respect  affect the validity of
this  Lease  (including  the date on which  the Term  ends) or any  other of the
obligations  of Tenant,  except that the term of this Lease  shall not  commence
until  Landlord  has  delivered  the  Expansion  Premises  to Tenant  vacant and
broom-clean  and given Tenant 14 days' prior written notice of the date on which
possession of the Expansion  Premises will be delivered.  If the delivery of the
Expansion Premises is delayed beyond July 1, 1997 for causes not attributable in
whole or in part to the action or inaction  of Tenant,  Tenant may give a 14-day
termination  notice to  Landlord.  This Lease shall  terminate 14 days after the
giving of such notice if the  Expansion  Premises  are not  delivered  to Tenant
before such time.

     Landlord shall endeavor to deliver the Second Expansion  Premises to Tenant
on September 1, 1997.  If there is a holding over or retention of  possession of
the Second Expansion  Premises,  or any portion thereof,  by any prior tenant or
occupant,  or if Landlord shall otherwise be unable to deliver possession of the
Second  Expansion  Premises  on  September  1,  1997 due to  causes  beyond  its
reasonable control,  then Landlord shall not be subject to any liability for the
failure or delay in giving possession, except that the Second Expansion Premises
shall not be added to the  Premises  until the  Second  Expansion  Premises  are
delivered  to Tenant  vacant and in  broom-clean  condition  but no earlier than
September 1, 1997. No such failure to give possession shall in any other respect
affect the validity of this Lease (including the date on which the Term ends) or
any other of the  obligations of Tenant.  Landlord hereby consents to a sublease
by Tenant of the Second Expansion Premises to J. Howard,  Inc.,  provided Tenant
furnishes  notice and a copy of such  sublease  within 30 days  after  execution
thereof. If Tenant executes such a sublease, the Second Expansion Premises shall
be deemed  delivered upon  expiration of the J. Howard,  Inc. lease and Landlord
shall be excused from the  obligation to deliver the Second  Expansion  Premises
vacant and in broom-clean condition.

     2.4 Term. This Lease is for an initial Term  beginning  on the Commencement
Date and ending on the Ending Date as set forth in Section 1.1.

     2.5 Option to Extend. The Lease may be extended for the  Extension Term set
forth in Section 1.1 (and Annual Fixed Rent for such Extension Term  determined)
in accordance with Section 4.1.2, time being of the essence to such exercise, so
long as at the time of such notice and at the  beginning of the  Extension  Term
Tenant is not in



                                      -6-





default  beyond any  applicable  notice and grace period.  All references to the
Term shall mean the Initial Term as it may be extended by any Extension Term.

     2.6  Existing  Lease  Extension.  Tenant  currently  occupies  the Existing
Premises in the Building  pursuant to a Lease with Landlord dated as of November
1, 1991 (the "Existing Lease"). The term of the Existing Lease shall be extended
until  the day  before  the  Rent  Commencement  Date  hereunder.  Upon the Rent
Commencement  Date,  the  Existing  Lease  shall  terminate  without any further
liability of Tenant to Landlord thereunder,  and Tenant shall continue to occupy
and lease the Existing Premises under the provisions of this Lease.

     2.7 Right of Refusal for W.R. Grace Space.  Prior to or simultaneously with
any offer by Landlord to lease all or a portion of the space on the 300 level of
the  East  Wing  of the  Building  currently  leased  to  W.R.  Grace  and  more
particularly described in Appendix E (the "W.R. Grace Space") to any third party
other than the tenant of such space or an  affiliate  of such  tenant,  Landlord
shall  offer to lease such space to Tenant on the same terms and  conditions  as
Landlord is then willing to lease such space to third parties provided, however,
that (a) Tenant shall lease the space in question for a time period  coterminous
with the term of this Lease,  as it may be extended,  (b) if there are less than
36 months  remaining  on the term of the  Lease at the time the  space  would be
added to the  Premises  hereunder,  Tenant  and  Landlord  mutually  agree on an
extension  of the Term to at  least 36  months  and (c) any free  rent  amounts,
tenant work  allowances,  or other similar  concessions to be provided under the
proposed  third party lease shall be prorated to account for any amount by which
the lease to Tenant is shorter than the proposed lease term to third parties.

     Any offer by Landlord  under this  Section 2.7 may be accepted by Tenant by
notice  given within 10 business  days of receipt of  Landlord's  offer.  In the
event that Tenant accepts any offer by Landlord under this Section,  the leasing
of such  additional  space shall be  documented  by an  Amendment to this Lease.
Tenant's  rights under this Section 2.7 shall be rendered  void,  at  Landlord's
election, if Tenant is in default (after expiration of any applicable notice and
cure  period) at the time  Landlord  offers any space to a third party or at the
time  Tenant's  lease of any  space  under  this  Section  2.7  would  otherwise
commence.

     2.8 Tenant Improvement  Allowance.  Landlord shall pay to Tenant the Tenant
Improvement  Allowance specified in Section 1.1 in up to two installments within
20 days after  presentation  by Tenant to Landlord of paid  invoices  for Tenant
Alterations in the Existing Premises and/or the Expansion Premises.



                                      -7-





                                   ARTICLE III
                                   -----------

                          Landlord Work and Tenant Work
                          -----------------------------

     3.1  Landlord  Work. Except as provided  in Section  5.2 and this  Section,
Landlord  shall not be required to perform any work in connection  with Tenant's
occupancy  of the  Premises.  Tenant  acknowledges  that  it has  had  the  full
opportunity to inspect the Premises.  Landlord,  at its sole expense,  shall (a)
recarpet the 200 level common area,  including  the stairs  leading from the 200
level to the 300 level; and (b) touch up paint such common areas, as Landlord in
its reasonable discretion deems necessary ("Landlord's Work").

     3.2      Tenant Alterations.

              3.2.1 General. "Tenant Alterations" shall mean all work, including
demolition,  improvements,  additions  and  alterations,  in or to the  Premises
exclusive of Landlord's Work.  Without limiting the generality of the foregoing,
except for Landlord  Work  described in Section 3.1,  Tenant  Alterations  shall
specifically  include all signs visible from the exterior of the  Premises,  and
any change in the exterior  appearance of the windows in the Premises (including
shades,  curtains  and the  like).  All Tenant  Alterations  shall be subject to
Landlord's  prior written  approval  which  approval  shall not be  unreasonably
withheld  or delayed  and shall be  arranged  and paid for by Tenant as provided
herein. Tenant shall neither propose nor effect any Tenant Alterations (i) which
might in any manner affect any structural  component of the Building (including,
without  limitation,  exterior walls,  exterior windows,  core walls,  roofs, or
floor  slabs),  (ii)  which  might  in any  respect  be  incompatible  with  the
electrical  or mechanical  components  or systems of the  Building,  (iii) which
might  materially  affect in any respect other space in the Building  other than
the Premises, including the exterior of the Building), (iv) which might diminish
the value of the Premises for any general purpose office use, (v) or which might
require any unusual  expense to re-adapt the  Premises  for any general  purpose
office use. In  addition,  with  respect to any floor not  occupied  entirely by
Tenant,   Tenant  shall  neither  propose  nor  effect  any  Tenant  Alterations
consisting of improvements,  additions, or alterations to the entranceway to the
Premises or any adjoining  elevator  lobby,  corridor,  or common area; and with
respect  to  floors  entirely  occupied  by  Tenant,  any such  work  will be in
compliance with this Article III.

              3.2.2  Construction  Documents. No  Tenant  Alterations  shall  be
effected  except in accordance  with complete,  consistent,  final  construction
drawings and specifications  ("Construction  Documents")  approved in advance by
Landlord  in  writing,  which  approval  shall not be  unreasonably  withheld or
delayed. The Construction Documents shall be prepared by an architect ("Tenant's
Architect")  experienced in the  construction  of tenant space  improvements  in
buildings in the greater Boston area and approved by Landlord in



                                      -8-





writing, which approval shall not be unreasonably withheld or delayed,  whenever
any  structural  component of the Building is affected or  architectural  design
services are required in Landlord's reasonable judgment.  Tenant shall be solely
responsible  for  the  liabilities  of and  expenses  of all  architectural  and
engineering  services  relating  to  Tenant  Alterations  and for the  adequacy,
accuracy,  and completeness of the Construction  Documents approved by Landlord,
even if Tenant's  Architect has been otherwise engaged by Landlord in connection
with the  Building.  The  Construction  Documents  shall set forth in detail the
requirements  for  construction  of  the  Tenant   Alterations   (including  all
architectural,  mechanical,  electrical  and  structural  drawings  and detailed
specifications),  shall be fully  coordinated  with one  another  and with field
conditions  as they exist in the Premises and  elsewhere  in the  Building,  and
shall show all work necessary to complete the Tenant  Alterations  including all
cutting,  fitting,  and  patching  and all  connections  to the  mechanical  and
electrical  systems and components of the Building.  Tenant shall be responsible
for ensuring  that the work  described in  Construction  Documents  submitted to
Landlord  for  approval  (i) complies  with all  applicable  laws,  regulations,
building codes,  and the highest design  standards,  (ii) does not in any manner
affect any structural component of the Building (including,  without limitation,
exterior walls, exterior windows, core walls, roofs or floor slabs), (iii) is in
all respects  compatible  with the  electrical  and  mechanical  components  and
systems  of the  building,  (iv)  does not  materially  affect  any space in the
Building other than the Premises  (including the exterior of the Building),  (v)
conforms  to floor  loading  limits,  (vi) and with  respect  to all  materials,
equipment and special designs,  processes, or products, does not infringe on any
patent  or  other  proprietary   rights  of  others.   Landlord's   approval  of
Construction  Documents  shall  only  signify  Landlord's  consent to the Tenant
Alterations shown thereon and shall not result in any responsibility of Landlord
concerning  compliance  of the Tenant  Alterations  with laws,  regulations,  or
codes,  coordination  of any  aspect of the  Tenant  Alterations  with any other
aspect of the Tenant Alterations or any component or system of the Building,  or
the feasibility of constructing the Tenant Alterations without damage or harm to
the Building, all of which shall be the sole responsibility of Tenant.

              3.2.3  Performance  of Tenant  Alterations.  The  identity  of any
person or entity  (including  any  employee or agent of Tenant)  performing  any
Tenant  Alterations  ("Tenant  Contractor") shall be subject to Landlord's prior
written approval,  which approval shall not be unreasonably withheld or delayed.
Once any Tenant  Contractor has been  approved,  then the same may thereafter be
used by Tenant until Landlord  notifies Tenant that such Tenant Contractor is no
longer approved for future Tenant Alterations projects. Tenant shall procure all
necessary  governmental  permits,  licenses and approvals before undertaking any
Tenant Alterations. Tenant shall perform all Tenant Alterations at Tenant's risk
in compliance with all applicable  laws, codes and regulations and in a good and
workmanlike  manner  employing  new  materials of good  quality and  producing a
result at least  equal in quality to the other parts of the  Premises.  When any
Tenant  Alterations  is in  progress,  Tenant shall cause to be  maintained  (i)
insurance as described in the Tenant




                                      -9-






Alterations  Insurance Schedule attached hereto as Appendix D naming Landlord as
an additional insured,  and (ii) a statutory lien bond pursuant to M.G.L. c.254,
ss.12 or any successor statute (or such other protection of Landlord's  interest
in the Building  against liens to which Landlord may  reasonably  agree) for the
benefit of  Landlord.  It shall be a  condition  of  Landlord's  approval of any
Tenant  Alterations  that  certificates  of such  insurance  and a lien  bond in
recordable  form (or other  equivalent  security  agreed to by  Landlord),  both
issued  by  responsible   insurance   companies  qualified  to  do  business  in
Massachusetts  and  reasonably  approved by Landlord,  shall have been deposited
with Landlord,  that Tenant has provided Tenant's certification of the insurable
value of the work in question for casualty insurance  purposes,  and that all of
the other  conditions of the Lease have been  satisfied.  Tenant shall reimburse
Landlord's reasonable out-of-pocket costs of reviewing plans for proposed Tenant
Alterations  other  than  the  initial  Tenant  Alterations.  Tenant  shall  pay
Landlord's  Agent a  supervisory  fee of 3% of the  cost of the  initial  Tenant
Alterations   performed  by  Tenant.   At  all  times  while  performing  Tenant
Alterations,  Tenant  shall  require  any Tenant  Contractor  to comply with all
applicable  laws,  regulations and permits  relating to such work of the Town of
Lexington. In performing Tenant Alterations, each Tenant Contractor shall comply
with  Landlord's  reasonable  requirements  relating to the time and methods for
such work,  use of delivery  elevators and other Building  facilities;  and each
Tenant  Contractor  shall not  interfere  or disrupt  any other  tenant or other
person using the Building except to a de minimis extent.  Landlord shall provide
adequate access to the Building at reasonable  times to each Tenant  Contractor.
Each Tenant  Contractor shall in all events work on the Premises without causing
labor disharmony,  coordination difficulties, or delay or impair any guaranties,
warranties  or  obligations  of any  contractors  of  Landlord.  If  any  Tenant
Contractor uses any Building  services or facilities,  such Contractor,  jointly
and  severally  with  Tenant,  shall agree to  reimburse  Landlord  for the cost
thereof based on Landlord's  schedule of charges  established  from time to time
(and  if no such  charges  have  been  established,  then  based  on  Landlord's
reasonable charge established at the time).

              3.2.4 Payment for Tenant  Alterations.  Tenant shall pay, prior to
the due date  thereof,  the entire  cost of all Tenant  Alterations  so that the
Premises shall always be free of liens for labor or materials. If any mechanic's
lien (which term shall include all similar liens  relating to the  furnishing of
labor and  materials)  is filed against the Premises or the Building or any part
thereof which is claimed by the  Contractor to be  attributable  to Tenant,  its
agents,  employees or  contractors  (other than on account of Landlord's  Work),
Tenant shall promptly discharge the same by payment or filing any necessary bond
within 20 days  after  Tenant has notice  (from any  source) of such  mechanic's
lien.  Landlord may, as a condition of its approval of any Tenant Alterations of
$100,000 or more,  require  Tenant to deposit  with  Landlord a bond,  letter of
credit or other similar security in the amount of Landlord's reasonable estimate
of the value of such Work  securing  Tenant's  obligations  to make payments for
such Work.



                                      -10-





                                   ARTICLE IV
                                   ----------

                                      Rent
                                      ----

              4.1.1 Annual Fixed Rent - Initial  Term.  Annual Fixed Rent during
the  initial  Term of this  Lease  shall be the  amount  per  annum set forth in
Section 1.1.

              4.1.2 Annual Fixed Rent - Extension  Term. If the Term is extended
for the Extension  Term,  then Annual Fixed Rent will be as set forth in Section
1.1.

     Fair  Market  Rent  for the  Premises  during  the  Extension  Term for the
purposes of  determining  the Annual Fixed Rent for the Extension  Term shall be
ascertained, and notice of extension given, as follows:

              (a) If Tenant  wishes  to  exercise  its  extension  option  under
Section 1.1, Tenant shall so notify Landlord no less than 12 months prior to the
date the Term is then  scheduled  to expire (the  "Extension  Notice").  Failure
timely to send a notice shall  constitute  a waiver of Tenant's  right to extend
the Term.  Tenant's  notice shall  specify which of the Existing  Premises,  the
Expansion  Premises,  the Second Expansion Premises and the W.R. Grace Space (if
it has been added to the  Premises)  Tenant  wishes to continue to occupy during
the Extension  Term.  Tenant may elect to extend the Term with respect to all or
any combination of such four components of the Premises,  but once the Extension
Notice is given,  such  election  shall be  irrevocable.  A failure to designate
components of the Premises in the  Extension  Notice shall be deemed an election
to extend with respect to the entire premises.

              (b) Not later than one (1) month  after  receipt of the  Extension
Notice,  Landlord shall give written  notice to Tenant setting forth  Landlord's
determination  of Fair Market Rent for each of the Lease years of the  Extension
Term (which may be different from year to year).

              (c) Tenant may  thereafter  invoke  arbitration  according  to the
procedure  set forth below or negotiate  with  Landlord with respect to the Fair
Market Rent. If Tenant accepts Landlord's estimate of the Fair Market Rent or if
the parties  reach  agreement on Fair Market Rent,  the parties shall execute an
agreement  specifying  the agreed Fixed Annual Rent  hereunder for the Extension
Term,  specifying the modifications to the Lease necessary if Tenant has elected
to extend with respect to less than all of the Premises  and  acknowledging  the
extension  of the Term.  If Tenant  invokes  arbitration  by  written  notice to
Landlord,  the matter of the Fair Market Rent  promptly  shall be  submitted  to
arbitration  in accordance  with the following  procedure.  Landlord  shall give
notice to Tenant of an appraiser  whom  Landlord  designates  to ascertain  such
rent. If within 10 days of such notice Tenant objects to such person then Tenant
shall give notice to Landlord and 



                                      -11-






designate another appraiser (and failure so to notify Landlord shall bind Tenant
to the  appraiser  designated  by  Landlord).  If within 10 days of such  notice
Landlord  objects to such person  (and  failure so to notify  Tenant  shall bind
Landlord to the appraiser designated by Tenant), then both such appraisers shall
meet and within 10 days of such objection designate a third appraiser, who alone
shall within 20 days of his or her designation  ascertain such fair market rent.
(If the two appraisers fail to designate the third  appraiser  within such time,
then either Landlord or Tenant may request the American Arbitration Association,
Boston Office to designate the third appraiser.) Any appraiser  designated shall
have had at least 10 years experience in the leasing, ownership or management of
office  buildings  similar in character to the Premises and shall be a member of
A.S.R.E.C.  or M.A.I. (or successor professional  organization) and duly qualify
as an expert witness over objection to give opinion  testimony  addressed to the
issue in a court of competent jurisdiction. Fair market rent shall be the Annual
Fixed Rent which a willing  tenant would pay to lease the Premises for each year
of the Extension Term in question under terms and conditions  substantially  the
same as those of this Lease, with the Premises considered free and clear of this
Lease and as though then  available for single or multiple  occupancies  for the
Permitted Uses (or any higher and better use then being made by Tenant,  the mix
of any multiple  occupancies  being what is then customary in light of good real
estate  practice)  in the  condition in which Tenant is required to maintain the
Premises (or if in Landlord's  reasonable  judgment Tenant Alterations have been
installed which adversely affect rental value and Landlord has the right to have
Tenant remove such Tenant  Alterations at the  termination of the Term,  then as
though such Tenant  Alterations  were removed),  based on rentals for comparable
space over a comparable period with appropriate adjustments made to such rentals
as necessary to establish  comparability,  with rental  historically  paid under
this Lease  disregarded and taking into account all other then relevant factors.
If the parties do not agree in writing on such rent, then the written opinion of
fair market rent of the appraiser so chosen shall  conclusively  establish  such
rent ("Fair Market  Rent").  Both parties shall have the  opportunity to present
evidence in accordance with reasonable  procedures  prescribed by the appraiser,
and the fee of the  appraiser  giving his or her written  opinion  shall be paid
equally by the  parties.  If Landlord  should  delay in giving the notice  which
begins the valuation  procedures  of this  paragraph,  or if the process  should
otherwise be delayed for any reason,  then such  procedures  shall  nevertheless
remain in effect and be  applicable  when and as invoked  with respect to Annual
Fixed Rent payable  during the Extension  Term.  Notwithstanding  the foregoing,
Landlord  agrees  to use  reasonable  efforts  to cause  the  arbitration  to be
completed  prior to the first day of the ninth  remaining  calendar month in the
Term.

     Unless the parties have already executed an agreement specifying the agreed
Annual  Fixed  Rent  hereunder  for the  Extension  Term and  acknowledging  the
extension  of the Term,  then on or before the first day of the ninth  remaining
calendar month in the Term (calculated  without regard to any future extension),
Tenant may  withdraw  its  exercise of Tenant's  extension  option  hereunder by
giving Landlord notice to such effect.



                                      -12-





              4.2.1 Method of Payment.  Tenant  covenants  and agrees to pay the
Annual Fixed Rent to Landlord in advance in equal  monthly  installments  (or in
the appropriate monthly  installments for monthly periods during any Lease year,
if and as referred to in Section  1.1) on the first day of each  calendar  month
during the Term beginning on the Rent Commencement Date. "Lease year" shall mean
the twelve month period following the Rent Commencement  Date. Tenant shall make
ratable  payment of Annual Fixed Rent for any portion of a Lease year (or month)
in which the same accrues, all payments of Annual Fixed Rent and additional rent
and other sums due hereunder to be paid in current U.S. exchange at the Original
Address of Landlord or such other place as Landlord  may by notice in writing to
Tenant  from time to time  direct (or if  requested  by  Landlord in the case of
Annual Fixed Rent,  by electronic  fund  transfer),  without  demand and without
set-off or deduction, except as set forth herein.

     Without limiting the generality of the foregoing, Tenant's obligation so to
pay shall not be discharged or otherwise  affected by reason of the  application
of any law or regulation  now or hereafter  applicable  to the Premises,  or any
other  restriction of or interference with the use thereof by Tenant, or (except
as and to the extent expressly  provided herein) any damage to or destruction of
the Premises by casualty or taking,  or on account of any failure by Landlord to
perform hereunder or otherwise,  or due to any other occurrence;  nor (except as
expressly  provided  herein)  shall  Tenant ever be entitled  and Tenant  hereby
waives all rights now or  hereafter  conferred  by statute or otherwise to quit,
terminate or surrender  this Lease or the  Premises or any part  thereof,  or to
assert any defense in the nature of constructive  eviction to any action seeking
to recover  rent.  Tenant  shall,  however,  have and  maintain,  subject to the
provisions  hereof, the right to seek and obtain from time to time judgments for
direct money damages  occasioned  by Landlord's  breach of the covenants of this
Lease.

              4.3.1  Additional Rent - Landlord's  Taxes.  Tenant  covenants and
agrees to pay to Landlord, as additional rent, Tenant's Tax Percentage Share (as
set forth in Section  1.1) of  Landlord's  Taxes  (hereafter  defined)  for each
fiscal tax period,  or ratable  portion  thereof,  included in the Lease Term in
monthly  installments  on the  first  day of each  month in  amounts  reasonably
estimated  from time to time by  Landlord  to  provide  for the full  payment of
Tenant's  obligation with respect to Landlord's Taxes on the date such Taxes are
due.

              4.3.2 Landlord's Taxes - Definition. "Landlord's Taxes" shall mean
all  taxes,  assessments,   betterments,   excises,  user  fees  and  all  other
governmental  charges and fees of any kind or nature,  or  impositions or agreed
payments in lieu  thereof or  voluntary  payments  made in  connection  with the
provision of  governmental  services or  improvements of benefit to the Building
(including any so-called linkage, impact or voluntary betterment payments),  and
all penalties and interest  thereon (but only if due to Tenant's failure to make
timely payments on account of Landlord's taxes), assessed or




                                      -13-






imposed  against the  Premises or the  property of which the Premises are a part
(including  without  limitation  any  personal  property  taxes  levied  on such
property or on fixtures or  equipment  used in  connection  therewith),  or upon
Landlord by virtue of its ownership thereof ("Landlord's  Taxes"),  other than a
federal  or state  income tax of general  application  and any  federal or state
inheritance  taxes. If during the Term the present system of ad valorem taxation
of property  shall be changed so that, in lieu of or in addition to the whole or
any part of such ad  valorem  tax there  shall be  assessed,  levied or  imposed
exclusively  on  owners or  lessees  of real  property  or any kind or nature of
federal,  state,  county,  municipal or other governmental capital levy, income,
sales,  franchise,  excise or similar tax,  assessment,  levy, charge or fee (as
distinct from the federal and state income tax or  inheritance  tax in effect on
the  Commencement  Date)  measured by or based in whole or in part upon Building
valuation,  mortgage  valuation,  rents  or any  other  incidents,  benefits  or
measures of real property or real property operations,  then any and all of such
taxes, assessments, levies, charges and fees, calculated as if the Building were
Landlord's sole asset and the rents  Landlord's  sole income,  shall be included
within the term  Landlord's  Taxes. To the extent any assessments or betterments
are permitted to be paid in  installments,  Landlord's  Taxes shall include such
assessments  or  betterments  only up to the amount of the  installment(s)  that
would be due during the relevant year if such betterment or assessment were paid
over the longest  period  permitted,  whether or not  Landlord  elects to pay in
installments.

     Landlord's Taxes include reasonable expenses,  including reasonable fees of
attorneys,  appraisers and other  consultants,  incurred in connection  with any
efforts  to  obtain  abatements  or  reductions  or  to  assure  maintenance  of
Landlord's  Taxes for any tax fiscal  year wholly or  partially  included in the
Term,   whether  or  not  such  efforts  involve  filing  of  actual   abatement
applications or initiation of formal  proceedings,  but only if such efforts are
successful.  Landlord's  Taxes  shall be reduced to the extent of any refund (in
excess of the cost of obtaining such refund) in the year in which such refund is
received.

              4.4.1 Additional Rent - Operating  Expenses.  Tenant covenants and
agrees to pay to Landlord,  as additional rent,  Tenant's  Operating  Percentage
Share (as set forth in Section 1.1) of Landlord's  Operating Expenses (hereafter
defined)  for each of  Landlord's  fiscal  years,  or ratable  portion  thereof,
included  in the Lease  Term in  monthly  installments  on the first day of each
month in advance,  based on amounts  reasonably  estimated  from time to time by
Landlord, and with a final payment adjustment between the Parties within 14 days
after Landlord provides Tenant a statement of Landlord's  Operating Expenses for
Landlord's  most recent  fiscal year. If Landlord does not render a statement of
Landlord's  Operating  Expenses  within 90 days after a particular  fiscal year,
then Tenant shall not be obligated to pay  installments of Landlord's  Operating
Expenses for the next fiscal year until such statement is rendered.  All monthly
installments deferred pursuant to the preceding sentence shall be due within ten
days after  Landlord  furnishes  the  statement for the fiscal year in question.
Tenant and its accountants may examine Landlord's books and



                                      -14-






records  supporting such statement of Landlord's  Operating  Expenses by written
request to Landlord within 30 days of receipt of such statement.

              4.4.2  Landlord's  Operating  Expenses -  Definition.  "Landlord's
Operating Expenses" means all costs incurred in servicing,  operating, managing,
maintaining,   and  repairing  the  Building  and  the  land,   facilities   and
appurtenances thereto,  including without limitation the costs of the following:
(i)  supplies,  materials  and  total  wage and  labor  costs  and all costs and
expenses of independent  contractors  paid or incurred on account of all persons
engaged in the  operation,  maintenance,  security,  cleaning  and repair of the
Building and the land,  facilities and appurtenances  thereto,  including social
security,  unemployment  compensation,  pension,  vacation,  sick pay and  other
so-called "fringe benefits"; (ii) services furnished generally to tenants of the
Building by Landlord;  (iii)  utilities  consumed  and expenses  incurred in the
operation of the Building and the land,  facilities and  appurtenances  thereto;
(iv)  casualty,  liability,  workmen's  compensation  and  all  other  insurance
expenses (and the amount of any deductible in the event of an insured loss), all
insurance to be in such amounts and insuring against such risks as Landlord may,
in its sole  discretion  from time to time decide;  (v) snow removal,  planting,
landscaping,  grounds and parking  operation,  maintenance and repair  expenses;
(vi) management fees which do not exceed those  customarily paid with respect to
buildings in the area which are similar to the  Building,  and fees for required
licenses or permits;  (vii) rental or reasonable  depreciation of equipment used
in the  operation  of the Building and the land,  facilities  and  appurtenances
thereto,  and personal  property taxes assessed upon such equipment;  and (viii)
expenses of periodic  testing to assure that the Premises and  surrounding  land
are free of hazardous materials,  agents or substances, and to assure compliance
with codes,  regulations  and laws.  In addition,  if Landlord from time to time
repairs or replaces any existing  improvements  or equipment or installs any new
improvements  or  equipment  to the  Building  for  the  purpose  of  decreasing
Operating   Expenses   (including   without   limitation   energy   conservation
improvements or other improvements),  then the cost of such items amortized over
their reasonable life,  together with an actual or imputed interest rate (at the
level not to exceed that then being charged by  institutional  first  mortgagees
for new  permanent  first  mortgage  loans on  buildings  in the area  which are
similar to the  Building)  shall be included in Landlord's  Operating  Expenses.
Costs  and  expenses  referred  to in  this  Section  shall  be  ascertained  in
accordance  with  generally  accepted  accounting  principles  and  allocated to
appropriate  fiscal  periods on the  accrual  method of  accounting.  Landlord's
Operating  Expenses shall not include  payments of principal,  interest or other
charges on  mortgages  or  payments  of any rent by  Landlord  on account of any
ground  lease of the land on which the  Building is situated or any lease of the
Building;   costs  of  work  or  services  for  particular   tenants  separately
reimbursable  to  Landlord by such  tenants;  advertising,  marketing  costs and
leasing  commissions;  any and all costs of removing hazardous waste or asbestos
from the Building  (except to the extent such removal is required as a result of
Tenant's  actions);  legal fees  incurred  by  Landlord  in  negotiating  and/or
enforcing leases; costs incurred by




                                      -15-





Landlord to ensure the Building's compliance with laws and regulations which are
in effect  as of the date the Lease  begins;  any  expenses  and costs for which
Landlord is reimbursed by its insurer or other parties;  costs  associated  with
the  operating of the business of the entity which  constitutes  Landlord as the
same are  distinguished  from the costs of operation of the Building,  including
the salaries and benefits of executive-level  personnel and the pro rata portion
of wages of any  employee who does not devote  substantially  all of his time to
the Building fairly  allocable to time spent on other matters (but  specifically
excluding wages and benefits of the assistant  property manager and the building
manager) and costs of so-called leasehold  improvements to rentable areas in the
Building.

     The term "Landlord's Operating Expenses",  shall not, however,  include the
following items:

         1.       the cost of any work or services  performed  for any tenant of
                  the  Building,  whether  at the  expense of  Landlord  or such
                  tenant, to the extent that such work or services are in excess
                  of the work or services which Landlord is furnishing to Tenant
                  under this Lease at the expense of Landlord;

         2.       Landlord's Taxes;

         3.       the cost of any repairs  made by Landlord to remedy  damage to
                  the extent caused by or resulting from the gross negligence of
                  Landlord, its agents, servants or employees;

         4.       any funds or money given to any tenants in cash,  by offset or
                  otherwise,  or the cost of any work  done for any  tenants  in
                  connection with the leasing of space in the Building;

         5.       that portion of any cost paid to a corporation or other entity
                  affiliated with Landlord (i.e., controlling,  controlled by or
                  under common control with Landlord)  which is in excess of the
                  amount   which   would  be  paid  in  the   absence   of  such
                  relationship;

         6.       financing and refinancing costs in respect of any indebtedness
                  of Landlord whether secured or unsecured,  including legal and
                  accounting  fees  and  expenses,   prepayment   penalties  and
                  interest and amortization payments in connection therewith;

         7.       rent and additional rent under any ground or underlying lease;



                                      -16-






         8.       franchise,    gross   receipts,    unincorporated    business,
                  inheritance,  foreign  ownership  or control  or income  taxes
                  imposed upon  Landlord or any taxes  similar to the  foregoing
                  excluded  items  (other  than sales taxes on items or services
                  otherwise includible in Operating Expenses);

         9.       costs incurred in connection  with the transfer or disposition
                  of direct or indirect  ownership  interests in the Building or
                  Landlord;

         10.      the  costs  of  repairs   or   restoration   necessitated   by
                  condemnation;

         11.      fines,   judgments  or  awards   against   Landlord  based  on
                  Landlord's  negligence,  willful  misconduct  or criminal  act
                  (except  to the  extent  all or any  portion  of  such  fines,
                  judgments  or  awards  represent  that  cost  of  maintenance,
                  repairs  or other  items  otherwise  includible  in  Operating
                  Expenses);

         12.      general overhead of Landlord's or the managing agent's office;

         13.      costs  resulting  from  Landlord's  default  under any  lease,
                  except  to the  extent  such  costs  represent  the  costs  of
                  maintenance,  repairs or other items  otherwise  includible in
                  operating expenses;

         14.      costs for purchasing works of fine art; and

         15.      items to the extent actually  reimbursed to Landlord  pursuant
                  to any warranties or guarantees.

         16.      capital  expenditures,  except as  expressly  included  in the
                  second sentence of Section 4.4.2.

     4.5  Allocation of Certain  Operating  Expenses.  If at any time during the
Term,  Landlord  provides services only with respect to portions of the Building
which  include the  Premises or incurs  other  Operating  Expenses  allocable to
portions of the Building which include the Premises  alone,  then such Operating
Expenses shall be charged entirely to those tenants,  including  Tenant, of such
portions  receiving  such  services,   notwithstanding   the  provisions  hereof
referring  to  Tenant's  Percentage  Share.  If,  during  any  period  for which
Landlord's Operating Expenses are being computed,  less than all of the Building
is occupied by tenants,  or if Landlord is not  supplying  all tenants  with the
services  being  supplied  hereunder,  Operating  Expenses  shall be  reasonably
estimated and extrapolated by Landlord to determine the Operating  Expenses that
would have been incurred if the Building  were fully  occupied for such year and
such  services  were being  supplied  to all  tenants,  and such  estimated  and
extrapolated amount shall be deemed to be Landlord's Operating Expenses for such
period.



                                      -17-






                                    ARTICLE V
                                    ---------

                              Additional Covenants
                              --------------------

     5.1 Tenant's Covenants.  Tenant covenants that at all times during the Term
and such  further time as Tenant (or persons  claiming by,  through or under it)
occupies  the  Premises or any part  thereof,  it shall  perform and observe the
following conditions, all at its sole cost and expense:

              5.1.1  Utilities  and  Services.  Tenant shall provide and pay all
charges and deposits for telephone  service.  It is  understood  and agreed that
except  as may be  expressly  provided  hereunder,  Landlord  shall  be under no
obligation  whatsoever to furnish any such  services to the Premises,  and shall
not be liable for (nor  suffer  any  reduction  in any rent on  account  of) any
interruption or failure in the supply of the same.

              5.1.2  Maintenance.  Except  to the  extent  that  same  shall  be
Landlord's  responsibility  hereunder,  Tenant shall maintain, repair and secure
the Premises,  all  improvements  and  appurtenances  thereto,  all access areas
thereof,  and all  utilities,  facilities,  installations  and equipment used in
connection therewith,  and shall pay all costs and expenses of so doing, keeping
the Premises in good order, repair and condition,  reasonable wear and tear, and
damage by  casualty  and  taking  (to the  extent  provided  in Article VI only)
excepted.  Without  limiting the generality of the foregoing,  Tenant shall keep
all  interior  walls,  floor  surfaces and  coverings,  glass,  windows,  doors,
partitions,  all fixtures and equipment,  utilities,  pipes and drains and other
installations  used in connection  with the Premises in such good order,  repair
and  condition,  shall provide all painting and floor  covering to the Premises,
except as  otherwise  stated in this Lease and shall  remove all refuse from the
Premises.  Landlord agrees to operate and maintain the Building as a first class
suburban office building.

     Attached  as Appendix B and a part hereof are  particular  requirements  of
certain  aspects of maintenance and operation of the Premises which Tenant shall
perform and conform to in addition to, and not in limitation of, the foregoing.

              5.1.3 Use and Compliance  with Law.  Tenant shall use the Premises
only for the Permitted Uses set forth in Section 1.1, and then only as permitted
under  laws,  regulations  and orders  applicable  from time to time,  including
without  limitation  municipal  by-laws,  land  use and  environmental  laws and
regulations,  and shall procure all  approvals,  licenses and permits  necessary
therefor,  in each case giving  Landlord  true and  complete  copies of the same
which affect the Building and all applications  therefor.  Tenant shall promptly
comply with all present and future laws applicable to Tenant's particular use of
the Premises or Tenant's signs thereon,  foreseen or unforeseen,  and whether or
not  the  same  necessitate   structural  or  other  extraordinary   changes  or
improvements to the Premises



                                      -18-






or  interfere  with its use and  enjoyment of the  Premises,  and shall keep the
Premises equipped with adequate non-structural safety appliances and comply with
all requirements reasonable in light of the use Tenant is making of the Premises
of insurance  inspection  or rating  bureaus  having  jurisdiction.  If Tenant's
particular  use of the  Premises  results in any increase in the premium for any
insurance  carried by Landlord,  then upon  Landlord's  notice to Tenant of such
increase  Tenant shall  either  cease the  relevant  activity or pay the same to
Landlord  within 20 days after demand as additional  rent.  Tenant shall, in any
event,  indemnify and save Landlord harmless from all loss, claim,  damage, cost
or expense (including reasonable attorneys' fees of counsel of Landlord's choice
against  whom  Tenant  makes no  reasonable  objection)  on account of  Tenant's
failure so to comply with the  obligations  of this Section  (paying the same to
Landlord upon demand as additional rent). Tenant shall bear the sole risk of all
present or future laws  affecting  Tenant's  particular  use of the  Premises or
appurtenances  thereto (as opposed to its mere occupancy thereof),  and Landlord
shall not be liable for (nor suffer any reduction in any rent on account of) any
interruption,  impairment or prohibition  affecting the Premises or Tenant's use
thereof  resulting from the enforcement of laws with which Tenant is responsible
for complying. Tenant shall conform to all reasonable rules and regulations from
time to time  promulgated  by Landlord  for the  operation,  care and use of the
common  areas of the Building and  appurtenant  improvements  and areas in which
Tenant is granted  rights of use by the terms of this Lease.  Landlord shall not
enforce or fail to enforce the Building  rules and  regulations in such a manner
as to discriminate against Tenant.  Notwithstanding  anything to the contrary in
this  Section,  Landlord  shall be  responsible  for  compliance  with  laws and
regulations  that  relate  to the  Building  generally  (except  those  laws and
regulations which apply specifically to Tenant's particular use of the Premises,
with respect to which Tenant shall be  responsible),  and Landlord shall pay for
the  cost of  installing  any life  safety  systems  which  are  installed  on a
Building-wide basis.

              5.1.4 Liens and  Encumbrances.  Tenant shall not create or suffer,
shall keep Landlord's property, the Premises and Tenant's leasehold free of, and
shall  promptly  remove and  discharge,  any lien,  notice of contract,  charge,
security interest,  mortgage (except for chattel mortgages,  equipment leases or
security  interests in Tenant's  movable  property) or other  encumbrance  which
arises for any reason,  voluntarily or involuntarily,  as a result of any act or
omission by Tenant or persons  claiming by,  through or under Tenant,  or any of
their agents, employees or independent contractors, including without limitation
liens which arise by reason of labor or  materials  furnished or claimed to have
been furnished to Tenant or for the Premises.

              5.1.5  Indemnity.  Tenant  shall assume  exclusive  control of all
areas of the Premises,  including all  improvements,  utilities,  facilities and
installations now or hereafter thereon,  and all liabilities,  including without
limitation tort  liabilities,  incident  thereto  relating to Tenant's acts; and
Tenant  shall  indemnify,  save  harmless  and  defend  Landlord  its  partners,
mortgagees, agents, employees, (collectively "Indemnitees") from all liability,



                                      -19-






claim  or  cost  (including   reasonable   attorneys'  fees  of  counsel  of  an
Indemnitee's  choice against whom Tenant makes no reasonable  objection) arising
in whole or in part out of any injury,  loss, theft or damage (except if such is
due to the  negligence  or misconduct  of Landlord or its  employees,  partners,
mortgagees  or agents) to any person or property  while on or about the Premises
or the  Reception  Area,  or out of any  condition  within the  Premises  or the
Reception  Area which is not  Landlord's  responsibility,  or arising out of any
breach of any Lease  covenant,  or from any act or omission of Tenant or persons
claiming  by,  through  or  under  Tenant,  or any of their  agents,  employees,
independent  contractors,  or invitees (while in the Premises only),  paying the
same to Landlord upon demand as additional rent. Landlord shall assume exclusive
control  of all common  areas of the  Building  (other  than  Tenant's  right to
operate the  Reception  Area) and Landlord  shall  indemnify,  save harmless and
defend Tenant from all liability, claim or cost (including reasonable attorneys'
fees of counsel of Tenant's  choice  against whom  Landlord  makes no reasonable
objection) arising in whole or in part out of any injury, loss or damage (except
if such is due to the  operation of the Reception  Area or to the  negligence or
misconduct of Tenant or its employees or agents) to any person or property while
on or about the common areas of the Building or out of any condition  within the
common areas of the Building.  The  provisions of this Section shall survive the
Term of this Lease.

              5.1.6  Landlord's  Right to  Enter.  Landlord  and its  agents  or
employees may upon  reasonable  notice enter the Premises  during business hours
(and in case of emergency at any time), for the purpose of exercising any of the
rights  reserved  to Landlord  herein,  or  securing  or  protecting  Landlord's
property or the Premises, or removing any alterations or additions not consented
to by Landlord,  and similarly upon  reasonable  notice may show the Premises to
prospective purchasers and lenders, and during the last 12 months of the Term to
prospective tenants.  Except in case of emergency,  Landlord shall be subject in
entering the Premises to reasonable  security  conditions,  if any, set forth by
Tenant in writing to Landlord.

              5.1.7 Personal  Property at Tenant's Risk. All of the furnishings,
fixtures,  equipment, effects and property of every kind, nature and description
which,  during the occupancy of the Premises by Tenant (or persons  claiming by,
through or under  Tenant) may be on the  Premises  or  elsewhere  on  Landlord's
property,  shall be at the sole risk and hazard of Tenant.  Except to the extent
such damage is caused by the negligence or misconduct or breach of this Lease by
Landlord  or its  employees,  Landlord  shall  not be  liable  for,  and  Tenant
expressly  waives all claims against  Landlord,  its agents and  employees,  for
damage to person or property  sustained  by Tenant,  or any person  claiming by,
through or under Tenant,  resulting from any accident or occurrence in or on the
Premises or the  property of which the Premises  are a Part,  including  but not
limited to, claims for damage resulting from water, wind, ice, steam,  explosion
or  otherwise,  or from the rising of water or the  leakage or bursting of water
pipes,  steam pipes,  gas pipes,  the sprinkler  system or other pipes,  or from
theft, vandalism, lack of repair, defect, structural




                                      -20-






or non-structural  failure, or from any other cause whatsoever,  and except only
to the extent  provided  above in this  Section,  no part of said loss or damage
shall be charged to or borne by Landlord or Landlord's agents or employees.

              5.1.8 Overloading, Nuisance, Etc. Tenant shall not, either with or
without  negligence,   injure,  overload,   deface,  damage  or  otherwise  harm
Landlord's property,  the Premises or any part or component thereof;  commit any
nuisance;  permit the emission of any hazardous agents or substances;  allow the
release  or other  escape  of any  biologically  or  chemically  active or other
hazardous  substances or materials so as to impregnate,  impair or in any manner
affect,  even  temporarily,  any element or part of  Landlord's  property or the
Premises,  or allow the storage or use of such  substances  or  materials in any
manner not  sanctioned  by law or by the  highest  standards  prevailing  in the
industry  for the storage and use of such  substances  or  materials;  nor shall
Tenant bring onto the Premises any such materials or substances except to use in
the ordinary course of Tenant's business,  and then only after written notice is
given to Landlord of the identity of such  substances or materials (the identity
of all such  substances and materials,  if any, so used on the date hereof being
set forth on Appendix C); permit the occurrence of objectionable noise or odors;
or make,  allow or suffer any waste  whatsoever  to  Landlord's  property or the
Premises.  Landlord may inspect the Premises  from time to time during  business
hours upon reasonable  notice,  and Tenant will cooperate with such inspections.
Without limitation, hazardous substances shall include such substances described
in the Comprehensive  Environmental Response,  Compensation and Liability Act of
1980,  as  amended,  42  U.S.C.  ss.9601  et seq.  and the  regulations  adopted
thereunder,  and hazardous  materials shall include such materials  described in
the Resource  Conservation  and Recovery Act, as amended,  42 U.S.C.  ss.6901 et
seq.; in the  Massachusetts  Hazardous Waste Management Act, as amended,  M.G.L.
Chapter 21, and the Massachusetts Oil and Hazardous  Material Release Prevention
Act, as amended,  M.G.L.,  Chapter 21E, and the regulations  adopted under these
acts. In addition, Tenant shall execute affidavits, representations and the like
from time to time at  Landlord's  reasonable  request  concerning  Tenant's best
knowledge and belief regarding the presence or absence of hazardous materials on
the Premises or land pertaining thereto.  In all events,  Tenant shall indemnify
Landlord and  mortgagees  in the manner  elsewhere  provided from any release of
hazardous materials on the Premises occurring while Tenant is in possession. (At
the request of Landlord, Tenant will from time to time confirm such indemnity to
mortgagees  directly with such  mortgagees.)  Landlord shall indemnify Tenant in
the manner  elsewhere  provided  from any release of  hazardous  materials in or
around the  Building  resulting  from any conduct or omission of Landlord or its
employees or agents.  Landlord  shall use  reasonable  efforts to notify  Tenant
promptly  if there is a release of  hazardous  materials  at the  Building  that
Landlord  believes  poses  threat to the  health or safety of  occupants  of the
Premises.



                                      -21-





              5.1.9 Yield Up. At the  expiration or earlier  termination of this
Lease, Tenant (and all persons claiming by, through or under it) shall,  without
the  necessity  of any notice,  surrender  the  Premises  (including  all Tenant
Alterations and all replacements thereof, except such additions, alterations and
other  Tenant  Alterations  as  Landlord  and Tenant  have  agreed  prior to the
installation of such Tenant Alterations that Tenant shall remove, which shall be
removed by Tenant and the Premises restored to their pre-existing condition) and
all keys to the Premises, remove all of its trade fixtures and personal property
not  permanently  attached to the  Premises  (and such trade  fixtures and other
property permanently attached to the Premises as Landlord and Tenant have agreed
prior to the installation of such Tenant  Alterations that Tenant shall remove),
and all Tenant's signs wherever  located,  in each case repairing  damage to the
Premises which results in the course of such removal.  Landlord  agrees that the
initial Tenant  Improvements to the extent  permanently  affixed to the Premises
and to the extent  approved by Landlord as required in Section  3.2.1,  shall be
left in the Premises at the expiration of the Term. Tenant shall have the right,
at the time it requests approval for Tenant  Alterations (other than the initial
Tenant  Alterations),   to  ask  Landlord's  permission  to  leave  such  Tenant
Alterations  in place  at the end of the Term  (which  permission  shall  not be
unreasonably  withheld) and if Landlord gives such permission,  Tenant shall not
be required to remove such  Tenant  Alterations  at the end of the Term.  Tenant
shall yield up the Premises broom-clean and in good order, repair and condition,
reasonable  wear and tear and  damage by  casualty  and  taking  (to the  extent
provided in Article VI only)  excepted.  Any  personal  property  not so removed
within thirty (30) days after the  expiration or  termination of the Lease shall
be deemed  abandoned  and may be removed  and  disposed  of by  Landlord in such
manner as Landlord shall determine,  and Tenant shall pay to Landlord the entire
cost and expense incurred by it in effecting such removal and disposition and in
making any incidental repairs to the Premises.

              5.1.10 Holding Over. If Tenant (or anyone  claiming by, through or
under  Tenant)  shall remain in  possession  of the Premises or any part thereof
after the  expiration or earlier  termination  of this Lease with respect to any
portion of the Premises without any agreement in writing executed with Landlord,
then the person  remaining in possession  shall be deemed a tenant at sufferance
of such possessed  space,  and Tenant shall thereafter pay Annual Fixed Rent for
the first month of holdover at 150% of, and for each month thereafter at 200% of
the amount  payable  for the twelve  month  period  immediately  preceding  such
expiration or termination  and with all additional rent payable and covenants of
Tenant in force as  otherwise  herein  provided,  and Tenant  shall be liable to
Landlord for all damages, including consequential damages, of such breach. After
acceptance  of the full  amount  of any  monthly  rent by  Landlord  the  person
remaining in  possession  shall be deemed a tenant from  month-to-month  at such
rent and otherwise subject to and having agreed to perform all of the provisions
of this Lease,  but Landlord will not be deemed to have  relinquished any claims
for damages.



                                      -22-




              5.1.11 Assignment, Subletting. Subject to Tenant's compliance with
the other  conditions  of this  Section,  Tenant  may,  without  the  consent of
Landlord,  assign  this Lease or sublet or license  the  Premises or any portion
thereof to (i) any affiliate or subsidiary of Tenant or (ii) to any other person
whose net worth is at least  equal to or greater  than  Tenant's  on the date of
such transfer,  provided that Tenant remains  primarily  liable under this Lease
("Permitted  Transfers").  Tenant  shall not  assign  this  Lease,  or sublet or
license the Premises or any portion  thereof,  or permit the occupancy of all or
any  portion of the  Premises by anybody  other than Tenant  except as set forth
herein (all of the foregoing actions are sometimes collectively referred to as a
"transfer") without obtaining,  on each occasion,  the prior consent of Landlord
which consent shall not be unreasonably  withheld,  delayed or  conditioned.  If
Landlord has not responded  within ten days after receiving  written notice from
Tenant requesting  Landlord's consent to a particular transfer,  then Tenant may
send a second  notice  stating that  Landlord's  consent to the transfer will be
deemed given if Landlord fails to respond within five days. If Landlord fails to
respond within five days after receipt of such a second  notice,  consent to the
transfer  shall be deemed  given.  A transfer  shall  exclude  any  transfer  of
Tenant's  interest in this Lease by operation of law, merger or consolidation of
Tenant into any other firm or corporation, the transfer or sale of a controlling
interest in Tenant  whether by sale of its  capital  stock or  otherwise  or any
liquidation  of Tenant or a substantial  part of Tenant's  assets  provided that
Tenant has given  Landlord prior written notice  thereof,  and provided  further
that the  successor  entity has a financial  net worth that is at least equal to
$25,000,000  (except with respect to the successor  entity created by a transfer
of capital  stock).  Tenant may also  sublease  a portion of the  Premises  to a
subsidiary or affiliate of Tenant without  Landlord's  consent,  provided Tenant
has given  Landlord  prior written  notice  thereof,  and provided  further that
Tenant  remains  primarily  obligated  under this Lease.  Landlord  shall not be
obligated  to  consent to a transfer  to (i) any tenant in the  Building  unless
Landlord has no comparable space available  (comparability to be determined with
respect to price,  size,  condition,  timing of availability and the like); (ii)
any party with whom, to Tenant's  knowledge,  Landlord is then  negotiating with
respect  to space in the  Building;  or (iii) any party  which  would be of such
type,  character  or condition  as to be  inappropriate  as a tenant for a first
class  office  building.  If Tenant  proposes an  assignment  of this Lease or a
sub-letting of all or  substantially  all of the Premises for the balance of the
Lease  Term,  Landlord  may elect by written  notice to Tenant  given  within 30
business days after Tenant's  proposal to terminate this Lease  contingent  upon
the  proposed  transferee  becoming  directly  obligated  to Landlord  upon such
proposed  terms;  and upon the proposed  assignee or  sub-tenant  so  obligating
itself,  Tenant shall  thereafter be free of further  obligation  hereunder.  If
Tenant does  transfer  with  Landlord's  consent,  where  Landlord's  consent is
required hereunder, and if the consideration,  rent, or other charges payable to
Tenant  under  such  transfer  exceed  the rent  and  other  charges  to be paid
hereunder  (pro-rated based on floor area in the case of a sub-letting,  license
or other  occupancy  of less  than the  entire  floor  area of the  Premises  in
question),  then Tenant shall pay to Landlord,  as additional  rent,  50% of the
amount  of  such  excess  when  and  as  received   less   Tenant's


                                      -23-


reasonable  out-of-pocket  expenses  incurred in such  subleasing or assignment.
Without limiting the generality of the foregoing, any lump-sum payment or series
of payments due which are not  reimbursements  for expenses  (including  for the
purchase of  so-called  leasehold  improvements  if in excess of the fair market
value  thereof)  on account of any  transfer  shall be deemed to be in excess of
rent and other charges in its or their entirety.

     Except for Permitted  Transfers,  Tenant shall give  reasonable  good faith
consideration  to any request by Landlord's  Managing  Agent,  Beal and Company,
Inc.  (or such other  manager  of the  Building  appointed  from time to time by
Landlord)  to be  Tenant's  co-exclusive  broker for a period of six months with
respect to any  proposed  transfer so long as Tenant  intends to engage a broker
(and  before so engaging  any broker  Tenant  will so notify  Landlord  and give
Landlord's  Agent, or such other manager,  such  consideration).  Such Agent (or
other  manager) if so engaged by Tenant  (Tenant  being under no  obligation  to
engage  Agent  or such  other  manager)  shall be paid a  brokerage  fee for any
transfer which it procured in accordance with such Agent's  commission  schedule
then in effect so long as such schedule is competitive with similar schedules of
major Greater Boston brokerage firms.

     Notwithstanding any transfer of this Lease,  Tenant's liability to Landlord
shall in all events  remain  direct and  primary.  In the case of any  requested
consent to a transfer,  Tenant shall deliver to Landlord at the time thereof (i)
a true and complete copy of the proposed instrument  containing all of the terms
and conditions of such transfer,  and (ii) a written  agreement of the assignee,
sub-tenant or licensee,  in  recordable  form  reasonably  approved by Landlord,
agreeing  with  Landlord to perform and observe all of the terms,  covenants and
conditions  of this Lease.  Tenant shall pay to Landlord,  as  additional  rent,
Landlord's  reasonable  out-of-pocket  attorneys' fees in reviewing any transfer
contemplated by this Section,  whether or not Landlord consents to the same. Any
transferee  of all or a  substantial  part of Tenant's  interest in the Premises
shall be  deemed  to have  agreed  directly  with  Landlord  to be  jointly  and
severally  liable with Tenant for the  performance of all of Tenant's  covenants
under this Lease from and after the date of transfer;  and such  assignee  shall
upon  request  execute  and deliver  such  instruments  as  Landlord  reasonably
requests in confirmation  thereof (and agrees that its failure to do so shall be
subject to the default  provisions).  If Tenant shall default hereunder and such
default shall continue  beyond any applicable  notice and cure period,  Landlord
may collect rent and other  charges from such  transferee  (and upon notice such
transferee shall pay directly to Landlord) and apply the net amount collected to
the rent and other charges  herein  reserved,  but no transfer shall be deemed a
waiver of the provisions of this Section, or the acceptance of the transferee as
a tenant,  or a release  of Tenant or any  guarantor  from  direct  and  primary
liability for the performance of all of the covenants of this Lease. The consent
by Landlord to any  transfer  shall not relieve  Tenant from the  obligation  of
obtaining the express  consent of Landlord to any  modification of such transfer
or a further assignment,  subletting, license or occupancy; nor shall Landlord's
consent  alter in any manner


                                      -24-


whatsoever the terms of this Lease,  to which any transfer at all times shall be
subject and subordinate.

     5.2 Building  Services.  Landlord  shall furnish the services and utilities
hereafter  described.  Tenant may obtain additional  services and utilities from
time to time if the same are  obtainable  by Landlord  upon  reasonable  advance
request, and Tenant shall pay for the same at reasonable rates from time to time
established  by Landlord  (which  rates shall be  determined  by Landlord as the
rates  reasonably  necessary  to  reimburse  Landlord  for  the  actual  cost of
providing  such  services)  within  20 days  after  demand as  additional  rent.
Landlord's  obligation  shall be subject to the other  provisions of this Lease,
reasonable  wear and tear and  damage  caused by or  resulting  from the acts or
omissions of Tenant or its transferees (or their agents, employees, invitees and
independent contractors), fire, casualty or eminent domain takings.

              5.2.1 Landlord's  Maintenance.  Landlord shall reasonably  repair,
maintain and replace, as necessary,  the foundations,  exterior walls,  masonry,
structural  floors and roof,  the  heating,  ventilating  and air  conditioning,
electrical and plumbing  systems,  and elevators of the Building insofar as such
elements  affect  the  Premises,  heating,  ventilating,  electrical,  plumbing,
air-conditioning  and other  mechanical  systems to the extent  located in party
walls and the exterior walkways, sidewalks, driveways and parking areas referred
to in Section 2.1; but in no event shall  Landlord be obligated to repair broken
glass,  windows or doors of the Premises,  whether  interior or exterior  (which
responsibility shall be Tenant's).

              5.2.2 Electricity. Landlord shall furnish to Tenant throughout the
Term ___ watts per rentable  square foot of 120 volt current.  Tenant  covenants
and agrees to pay, as an additional  charge,  the cost of such  electricity,  as
reasonably  estimated  by  Landlord,  in  accordance  with  engineering  studies
conducted at Landlord's cost, to reimburse  Landlord for the actual cost of such
electricity. Tenant shall pay such estimated electricity charges monthly, with a
readjustment,  if necessary,  to be made after actual charges are determined and
allocated at the end of each year of the Lease Term.

              5.2.3 Office  Identification.  Subject to Section 5.1.3,  Landlord
shall provide and install, at Landlord's  expense,  letters or numerals on entry
doors  to the  Premises  and on the  Building  Directory  to  identify  Tenant's
official name and Building  address;  all such letters and numerals to be in the
Building standard graphics.

              5.2.4 Grounds  Maintenance.  Landlord  shall  maintain the grounds
adjacent to the Building and the walkways,  driveways and parking areas referred
to in Section 2.1 in a first class manner.


                                      -25-



              5.2.5  Security.   Landlord,   as  part  of  Landlord's  Operating
Expenses,  shall continue to provide the existing  level of security  patrols in
the  Building,  so  long  as no  tenant  in the  Building  refuses  to  pay  its
proportional share of the cost thereof.

              5.2.6 Cleaning. Landlord, at its expense, shall cause the Premises
(other than the Storage Space) to be reasonably  cleaned in accordance  with the
specifications annexed as Appendix F.

              5.2.7 Heat and  Air-Conditioning.  Landlord  shall furnish  water,
heat and  air-conditioning  to the Premises on Mondays through Fridays excepting
legal  holidays  (legal  holidays shall consist of ten days to be agreed upon by
Landlord and Tenant on an annual basis) from 8:00 a.m. to 6:00 p.m.  (such hours
on such days being  referred to as  "business  days") and on any other days upon
Tenant's   request.   If  Tenant   requests   Landlord   to   provide   heat  or
air-conditioning after 6:00 p.m. on any business day, on Saturday,  Sunday or on
a legal  holiday,  Tenant  shall  pay  Landlord  therefor  at  rates  reasonably
established  by Landlord  from time to time (the  current  rate being $86.00 per
hour).

     5.3 Interruptions.  Landlord shall not be liable to Tenant in damages or by
reduction of rent or otherwise  by reason of  inconvenience  or annoyance or for
loss of business  arising from Landlord or its agents or employees  entering the
Premises  for any of the  purposes  authorized  in this Lease or for  repairing,
altering  or  improving  the  Building  in a manner  reasonable  in light of the
circumstances.  In case Landlord is prevented or delayed from making any repairs
or  replacements  or furnishing any services or performing any other covenant or
duty to be performed on Landlord's part by reason of any cause reasonably beyond
Landlord's control,  Landlord shall not be liable to Tenant therefor,  nor shall
the same give rise to a claim in Tenant's  favor that such  failure  constitutes
actual or constructive,  total or partial, eviction from the Premises.  Landlord
shall promptly  commence cure of such  interruption  to the extent  possible and
diligently  pursue such cure to completion.  If the heating or air  conditioning
systems  shall  fail and  Landlord  reasonably  decides  that the  circumstances
warrant providing such services from other facilities within the Building,  then
Tenant shall pay the cost of such replacement  services, as reasonably estimated
by  Landlord,  to or as  directed  by  Landlord  on demand as  additional  rent.
Landlord  reserves  the  right to stop  any  service  or  utility  system,  when
necessary by reason of accident or emergency,  or until  necessary  repairs have
been completed;  provided,  however, that in each instance of stoppage, Landlord
shall give Tenant such notice as is practicable  under the  circumstances of the
expected  duration of such  stoppage and will exercise  reasonable  diligence to
eliminate the cause thereof.  Except in case of emergency  repairs Landlord will
give Tenant reasonable advance notice of any contemplated  stoppage and will use
reasonable  efforts  to avoid  unnecessary  inconvenience  to  Tenant  by reason
thereof.  If  Tenant  is  unable to  occupy  the  Premises  for more than  three
consecutive  business  days as a result of a  stoppage  of a service  or utility
system or a  condition  that  results  in a  governmental  order to  vacate  the
Premises  and such


                                      -26-


stoppage or  condition  is not due to any act or  omission of Tenant,  then rent
hereunder  shall  abate  until such time as such  service  or utility  system is
restored or such  condition  is remedied  to the extent  necessary  to bring the
Premises back to a habitable condition.


                                   ARTICLE VI
                                   ----------

                           Insurance; Casualty; Taking
                           ---------------------------

              6.1.1 Public Liability Insurance. Tenant shall obtain and maintain
throughout the Term comprehensive  public liability insurance against all claims
and demands  for any injury to persons or property  which may be claimed to have
occurred  on or in  connection  with the  Premises  as a  result  of the acts or
omissions of Tenant,  naming Landlord and, if requested,  Landlord's  mortgagees
and other persons  designated by Landlord as additional  insureds,  in an amount
which shall,  at the  beginning of the Term, be at least equal to the amount set
forth in Section  1.1,  and from time to time  during the Term shall be for such
higher  amount,  if any, as directed  by Landlord  based on amounts  customarily
carried in the Boston  metropolitan area with respect to property similar to and
used for similar  purposes as Tenant then is using the Premises.  Such insurance
shall provide that it will not be subject to cancellation, termination or change
except after at least 20 days' prior written notice to Landlord (and  Landlord's
mortgagees  and such  additional  insureds).  The policy or policies,  or a duly
executed  certificate  or  certificates  for the same,  shall be deposited  with
Landlord at the beginning of the Term, and renewals of such policies shall be so
deposited not less than 20 days prior to the expiration of coverage.

              6.1.2   Insurance By Landlord.

                      (a) In the event Tenant  breaches any covenant or fails to
observe any condition set forth above in this Article VI, then without  limiting
any other right or remedy,  and, provided the required insurance has not lapsed,
any  applicable  notice  and cure  period  (or  without  notice and cure if such
insurance has lapsed),  Landlord may  immediately  and without  notice to Tenant
obtain such  insurance,  and Tenant  shall pay the cost  thereof and  Landlord's
reasonable  expenses  related  thereto  within  twenty (20) days after demand as
additional rent.

                      (b)  Landlord  shall  maintain   commercially   reasonable
casualty insurance on the Building.

     6.2 Waivers of  Subrogation.  Any insurance  carried by either  Landlord or
Tenant with respect to the Premises or property  therein or occurrences  thereon
shall  include  a  clause  or  endorsement  denying  to the  insurer  rights  of
subrogation against the other party to the extent rights have been waived by the
insured hereunder prior to occurrence of


                                      -27-


injury or loss.  Without limiting any other provisions of this Lease, each party
hereby waives any rights of recovery against the other for injury or loss due to
hazards  covered by such  insurance,  to the extent only of the  indemnification
received thereunder.

     6.3 Damage or Destruction of Premises.  If the Premises or any part thereof
shall be  damaged  by fire or  other  insured  casualty,  then,  subject  to the
following  provisions of this Section,  Landlord  shall proceed with  diligence,
subject to then applicable statutes, building codes, zoning ordinances and other
laws and  regulations  of any  governmental  authority,  and at the  expense  of
Landlord  (but  only to the  extent  of  insurance  proceeds  received  and made
available to Landlord by any  mortgagee)  to repair or cause to be repaired such
damage,  excluding  any items  installed  or paid for by Tenant  which Tenant is
permitted   to  remove  upon   expiration,   (which   items  shall  be  Tenant's
responsibility to repair.) If (i) all or any substantial part (meaning more than
25% of floor area or of insurable value) of the Premises are materially  damaged
by fire or other casualty (whether or not insured) or (ii) the Building (whether
or not  including  any portion of the  Premises)  is so damaged by fire or other
casualty (whether or not insured) that substantial alteration, reconstruction or
demolition of the Building shall in Landlord's  sole  discretion be appropriate,
or (iii) if any casualty occurs to the Premises during the last year of the Term
and its repair will reasonably  cost more than $100,000,  then in any such case,
this Lease and the Term hereof may be  terminated at the election of Landlord by
a notice in writing of its election so to terminate  given to Tenant  within six
(6) months  following the date of the casualty,  the effective  termination date
being  not less  than  thirty  (30) nor more than  sixty  (60) days  thereafter.
Landlord  shall notify Tenant in writing  within  seventy-five  (75) days of the
date of casualty  whether  Landlord  elects to repair the damage or to terminate
the Lease in accordance  with the terms of this Section.  If Landlord  elects to
repair the damage,  such notice shall include Landlord's estimate of the time to
repair.  Notwithstanding  anything to the contrary  herein,  if the Premises are
substantially  damaged so as to prevent  Tenant from using the  Premises for its
intended purposes,  Tenant shall have the right to terminate this Lease by prior
written  notice  thereof  either  (i)  within  fifteen  days  after  receipt  of
Landlord's  notice electing to repair the damage if Landlord  estimates that the
repair  will take  longer  than six (6) months to  complete  or (ii) if Landlord
fails to repair the damage prior to the later of six (6) months from the date of
Landlord's notice or such longer time period as Landlord estimates in Landlord's
notice.

     Tenant  shall be entitled  to a just  abatement  of Annual  Fixed Rent (and
additional rent on account of Landlord's  Taxes and Operating  Expenses)  during
the period of impaired  use of the Premises  (including  a partial  abatement if
only a portion  of the  Premises  is  untenantable).  If any  mortgagee  refuses
without  fault  by  Tenant  to  permit  insurance  proceeds  to  be  applied  to
replacement  of the  Premises,  and  neither  Landlord  nor such  mortgagee  has
commenced such replacement  within six (6) months  following  adjustment of such
casualty  loss with the  insurer,  then Tenant may,  until any such  replacement
commences,  terminate  this  Lease by giving  at least  thirty  (30) days  prior
written  notice


                                      -28-


thereof to Landlord.  Except as provided in this paragraph,  Tenant's obligation
to pay all rent and to perform and observe all other covenants and conditions of
this Lease shall not be affected by any damage or casualty, and the Term of this
Lease and rent hereunder shall continue nonetheless.

     6.4 Eminent Domain.  In the event that all or any  substantial  part of the
Premises  or the  Building  (meaning in either case more than 25% of floor area)
are taken (other than for temporary use, which shall be a taking for ninety (90)
days or less,  hereafter  described) by public  authority under power of eminent
domain (or by  conveyance  in lieu  thereof),  then by notice given within three
months following the recording of such taking (or conveyance) in the appropriate
registry of deeds,  this Lease may be terminated at Landlord's  election 30 days
after such notice,  and rent shall be apportioned as of the date of termination.
If this Lease is not terminated as aforesaid, Landlord shall within a reasonable
time thereafter,  diligently restore what may remain of the Premises  (excluding
any items  installed  or paid for by Tenant  which Tenant is permitted or may be
required to remove upon expiration) to a tenantable condition. If Landlord fails
to restore the Premises within six (6) months from the date of the notice of the
taking (or 90 days in the case of the last Lease  Year),  Tenant  shall have the
right to terminate this Lease by prior written notice thereof. In the event some
portion of rentable  floor area is taken (other than for temporary use) and this
Lease is not  terminated,  Annual Fixed Rent (and  additional rent on account of
Landlord's Taxes and Operating Expenses) shall be proportionally  abated for the
remainder  of the Term.  In the event of any taking of the  Premises or any part
thereof for temporary use, (i) this Lease shall be and remain unaffected thereby
and rent shall not abate,  and (ii)  Tenant  shall be  entitled  to receive  for
itself such  portion or portions of any award made for such use with  respect to
the period of the taking which is within the Term,  provided that if such taking
shall remain in force at the  expiration or earlier  termination  of this Lease,
then  Tenant  shall  pay to  Landlord  a sum  equal  to the  reasonable  cost of
performing  Tenant's  obligations  hereunder  with  respect to  surrender of the
Premises and upon such  payment  shall be excused  from such  obligations.  If a
taking affects a substantial  portion of the Premises  (meaning more than 15% of
floor area) and is not a temporary taking (as defined above),  Tenant shall have
the option to  terminate  this Lease upon not less than ninety (90) days' notice
to Landlord given within thirty (30) days after Tenant  receives  notice of such
taking.  If a taking results in the termination of this Lease,  the Annual Fixed
Rent and additional rent on account of Landlord's  Taxes and Operating  Expenses
shall be abated on a pro rata basis as of the date of such termination.

     Any specific  damages which are  expressly  awarded to Tenant on account of
its relocation expenses, and specifically so designated, shall belong to Tenant.
Except as  provided  in the  preceding  sentences  of this  paragraph,  Landlord
reserves to itself,  and Tenant releases and assigns to Landlord,  all rights to
damages  accruing on account of any taking or by reason of any act of any public
authority for which  damages are payable.


                                      -29-



Tenant  agrees to execute  such  further  instruments  of  assignment  as may be
reasonably requested by Landlord,  and to turn over to Landlord any damages that
may be recovered in any proceeding or otherwise.


                                   ARTICLE VII
                                   -----------

                                     Default
                                     -------

    7.1 Events of Default.  (a) If Tenant  fails to pay Annual Fixed Rent or any
additional rent or other sum or charge hereunder and such default  continues for
ten (10) days after notice; or (b) if any assignment shall be made by Tenant (or
any  assignee  of Tenant)  for the  benefit  of  creditors,  or (e) if  Tenant's
leasehold  interest  shall be taken on execution or by other  process of law and
all  rights of appeal  have been  exhausted,  or (f) if a  petition  is filed by
Tenant for adjudication as a bankrupt,  or for  reorganization or an arrangement
under any provision of any bankruptcy act then in force and effect, or (g) if an
involuntary petition under the provisions of any bankruptcy act is filed against
Tenant  (or any  assignee  of  Tenant)  and  such  involuntary  petition  is not
dismissed within ninety (90) days thereafter,  or (h) if Tenant (or any assignee
of Tenant) shall be declared bankrupt or insolvent according to law, or (i) if a
receiver,  trustee or assignee  shall be  petitioned  for and not  contested  by
Tenant for the whole or any part of Tenant's property, or if a receiver, trustee
or assignee shall be appointed over Tenant's objection and not be removed within
sixty (60) days  thereafter,  or (j) if any  representation  or warranty made by
Tenant  shall be  untrue in any  material  respect,  or (k) if  Tenant  fails to
perform any other  covenant,  agreement or condition  hereunder and such default
continues for thirty (30) days after notice (provided, however, that such thirty
(30) day period shall be reasonably extended in the case of non-monetary default
if the  matter  complained  of can be cured,  but the cure  cannot be  completed
within  such  period and Tenant  begins  promptly to cure within such period and
thereafter  diligently completes the cure), then, and in any such case, Landlord
and its agents and employees  lawfully may, in addition to and not in derogation
of any remedies for any preceding breach, immediately or at any time thereafter,
without  demand or  notice  and with  process  of law,  enter  into and upon the
Premises  or any part  thereof  in the name of the  whole,  or mail or deliver a
notice of  termination of the Term addressed to Tenant at the Premises or at any
other address herein  provided,  and thereby  terminate this Lease and repossess
the same as of Landlord's former estate. Upon such entry or mailing or delivery,
as the case may be, the Term shall terminate, all executory rights of Tenant and
all  obligations  of Landlord  under this Lease  shall  immediately  cease,  and
Landlord may expel Tenant and all persons  claiming by,  through or under Tenant
and remove its and their  effects in  accordance  with law without  being deemed
guilty of any manner of trespass and without  prejudice  to any  remedies  which
might  otherwise be used for arrears of rent or prior breach of  covenants;  and
Tenant  hereby  waives  all  statutory  and  equitable  rights to its  leasehold
(including without


                                      -30-


limitation  rights in the  nature of  further  cure or of  redemption,  if any).
Landlord may,  without notice,  store Tenant's  effects (and those of any person
claiming by,  through or under Tenant) at the expense and risk of Tenant and, if
Landlord so elects,  may sell such  effects at public  auction or auctions or at
private  sale or sales after  seven (7)  business  days notice to Tenant  (which
notice Tenant agrees is reasonable) and apply the net proceeds to the payment of
all sums due to Landlord from Tenant, if any, and pay over the balance,  if any,
to Tenant.  Tenant agrees that a notice by Landlord  alleging any default shall,
at  Landlord's  option (the  exercise of such option  shall be  indicated by the
inclusion of the words "notice to quit" in such notice),  constitute a statutory
notice  to quit and  waives  any  further  notices  to quit or of  intention  to
re-enter,  and any grace periods provided for herein shall run concurrently with
any statutory  notice periods.  If any payment of Annual Fixed Rent,  additional
rent,  or other  payment due from Tenant to Landlord is not paid when due,  then
Landlord may, at its option, in addition to all other remedies hereunder, impose
a late charge on Tenant equal to 5% of the amount in question, which late charge
will be due upon demand as additional rent.

     7.2      Remedies for Default.

              (a) Reletting  Expenses  Damages.  If this Lease is terminated for
default,  then Tenant covenants,  as an additional  cumulative  obligation after
such termination, to pay all of Landlord's reasonable costs and expenses related
thereto or in collecting amounts due hereunder,  including  reasonable attorneys
fees, and all of Landlord's reasonable expenses in connection with reletting the
Premises,   including  without   limitation,   tenant   inducements,   brokerage
commissions,  fees for legal  services,  reasonable  expenses of  preparing  the
Premises for  reletting  and the like  ("Reletting  Expenses").  It is agreed by
Tenant that Landlord may (i) relet the Premises or any part or parts thereof for
a term or terms  which  may at  Landlord's  option  be equal to or less  than or
exceed the period  which would  otherwise  have  constituted  the balance of the
Term,  and may grant such tenant  inducements  as Landlord in its sole  judgment
considers advisable, and (ii) make such alterations,  repairs and decorations in
the  Premises  as  Landlord  in its sole  discretion  considers  advisable  to a
customary  standard of improvement only, and no action of Landlord in accordance
with the  foregoing  nor any  failure  to relet or to  collect  rent  under  any
reletting shall operate or be construed to release or reduce Tenant's liability,
provided  however  that  Landlord  shall  make  reasonable  efforts to relet the
Premises and mitigate its other  damages.  Any  obligation to relet the Premises
imposed  upon  Landlord  by  law  shall  be  subject  to  Landlord's  reasonable
objectives of developing  its property in a harmonious  manner with  appropriate
mixes of tenants,  uses, floor areas, terms, etc. Landlord's  Reletting Expenses
together with all sums otherwise  provided for in this Lease,  whether  incurred
prior to or after  such  termination,  shall be due and  payable  within 20 days
after notice from Landlord.


                                      -31-


              (b) Termination  Damages. If this Lease is terminated for default,
then unless and until Landlord elects lump sum liquidated  damages  described in
(c) below Tenant  covenants,  as an additional  cumulative  obligation after any
such  termination,  to pay  punctually  to  Landlord  all the sums which  Tenant
covenants  in this Lease to pay in the same manner and to the same extent and at
the same  time as if this  Lease had not been  terminated.  In  calculating  the
amounts to be paid by Tenant pursuant to the preceding  sentence Tenant shall be
credited  with the net proceeds of any rent then  actually  received by Landlord
from a reletting of the Premises  after  deducting all sums provided for in this
Lease to be paid by Tenant and not then paid.

              (c) Lump Sum Liquidated  Damages.  If this Lease is terminated for
default,  then Tenant covenants,  as an additional  cumulative  obligation after
termination, to pay forthwith to Landlord at Landlord's election made by written
notice to Tenant at any time after  termination,  as liquidated damages a single
lump sum payment  equal to the sum of (i) all sums provided for in this Lease to
be paid by Tenant and not then paid at the time of such election,  plus (ii) the
excess of all of the rent reserved for the residue of the Term (with  additional
rent on account of Landlord's Taxes and Operating Expenses deemed to increase 5%
in each year on a compounding  basis) over all of the rent actually received (or
which rent Tenant shows by clear and convincing  evidence will be received),  on
account of the Premises  during such period,  which rent from reletting shall be
reduced by  reasonable  projections  of vacancies  and by  Landlord's  Reletting
Expenses described above to the extent not theretofore paid to Landlord.

     7.3 Remedies Cumulative. Any and all rights and remedies Landlord or Tenant
may have under this Lease, and at law and equity,  shall be cumulative and shall
not be deemed  inconsistent  with each other  (except with respect to liquidated
damages as set forth in the last  paragraph of Section 7.2), and any two or more
of all such rights and  remedies  may be  exercised  at the same time insofar as
permitted  by law.  Nothing  contained in this Lease  shall,  however,  limit or
prejudice  the  right of  Landlord  to  prove  and  obtain  in  proceedings  for
bankruptcy or insolvency by reason of the  termination of this Lease,  an amount
equal to the maximum allowed by any statute or rule of law in effect at the time
when and  governing  the  proceedings  in which the  damages  are to be  proved,
whether such amount be greater, equal to, or less than the amount of the loss or
damages referred to in the preceding Section.

     7.4 Effect of Waivers of Default.  Any consent or permission by Landlord or
Tenant to any act or omission which  otherwise would be a breach of any covenant
or condition,  or any waiver by Landlord or Tenant of the breach of any covenant
or  condition,  shall not in any way be held or  construed  to  operate so as to
impair the  continuing  obligation of such  covenant or condition,  or otherwise
operate to permit other similar acts or omissions.  No breach shall be deemed to
have been  waived  unless and until such  waiver be in writing and signed by the
party  granting  such  waiver.  The failure


                                      -32-


of either  party to seek  redress  for  violation  of or insist  upon the strict
performance  of any  covenant  or  condition  of this  Lease,  or the receipt by
Landlord of rent with knowledge of any violation,  shall not be deemed a consent
to or waiver of such  violation,  nor shall it prevent a subsequent  act,  which
would otherwise constitute a violation, from in fact being a violation.

     7.5 No Accord and Satisfaction;  No Surrender. No acceptance by Landlord of
a lesser sum than the Annual  Fixed  Rent,  additional  rent or any other sum or
charge  then due shall be deemed to he other  than on  account  of the  earliest
installment  of such  rent,  sum or charge  due;  nor shall any  endorsement  or
statement  on any check or in any  letter  accompanying  any check or payment be
deemed an accord and satisfaction, and Landlord may accept such check or Payment
without prejudice to Landlord's right to recover the balance of such installment
or pursue any other right or remedy  available  to it. The  delivery of keys (or
any similar  act) to  Landlord  or any agent or  employee of Landlord  shall not
operate as a  termination  of this lease or an  acceptance of a surrender of the
Premises.

     7.6 Waiver of Jury.  Landlord and Tenant  hereby waive trial by jury in any
summary  proceeding in any emergency or other statutory remedy, or in any action
based,  in whole or in part, on  non-payment  of rent; and Tenant further agrees
that it shall not interpose any  counterclaim  or set-off in any such proceeding
except  to the  extent  such  counterclaim  or  set-off  is  required  under the
applicable  rules of  procedure  to be raised in the same action or to avoid its
waiver.

     7.7 Landlord's  Curing and Enforcement.  If Tenant shall neglect or fail to
perform or observe any  covenant or  condition  of this Lease and shall not cure
such default  within the  applicable  cure period,  Landlord may, at its option,
without  waiving any claim for breach,  at any time thereafter cure such default
for the  account of  Tenant,  and any amount  reasonably  paid or any  liability
reasonably incurred by Landlord in so doing shall be deemed paid or incurred for
the account of Tenant after notice  thereof to Tenant  (except in an emergency),
and Tenant shall reimburse  Landlord  therefor,  together with an administrative
charge of five (5%) per cent of the amount thereof,  within 20 days after notice
as  additional  rent;  and Tenant  shall  further  indemnify  and save  Landlord
harmless in the manner  elsewhere  provided in this Lease in connection with all
of  Landlord's  actions  in  effecting  any  such  cure  except  for  Landlord's
negligence or willful  misconduct.  Notwithstanding  any other provision  herein
concerning cure periods, Landlord may cure any default for the account of Tenant
after such notice to Tenant,  if any, as is reasonable  under the  circumstances
(including  telephone  notice)  if the  curing  of  such  default  prior  to the
expiration  of the  applicable  cure period is  reasonably  necessary to prevent
likely  damage to the  Premises  or other  improvements  or  possible  injury to
persons,  or to protect  Landlord's  interest in its  property or the  Premises.
Tenant shall pay to Landlord on demand as additional  rent all of the reasonable
costs and  expenses  of  Landlord,  including


                                      -33-

such administrative charge and reasonable attorneys' fees, incurred in enforcing
any  covenant or  condition  of this Lease.  Without  limiting  any of its other
rights or remedies, any sum due hereunder shall, in addition, bear interest from
the date due at the  greater of (i) one and  one-half (1 1/2%) per cent for each
month (or ratable portion  thereof) the same remains unpaid,  or (ii) three (3%)
per cent per annum (or ratable  portion  thereof)  above the  so-called  base or
prime lending rate charged by State Street Bank and Trust Company of Boston from
time to time on 90 day loans to its most credit-worthy borrowers;  provided that
interest shall never exceed the maximum rate permitted under applicable law.

     7.8  Landlord's  Default.  In no event shall  Landlord be in default unless
notice  thereof has been given to Landlord  (and all  mortgagees of which Tenant
has notice) and Landlord (or any such mortgagee at its sole discretion) fails to
perform  within 30 days  (provided,  however,  that such 30 day period  shall be
reasonably  extended in the event of non-monetary  defaults if such  performance
begins  within such period and  thereafter  is  diligently  pursued,  or if such
mortgagee  notifies  Tenant within such period that it intends to cure on behalf
of Landlord and thereafter begins and diligently  pursues curing with reasonable
promptness).


                                  ARTICLE VIII
                                  ------------

                            Miscellaneous Provisions
                            ------------------------

     8.1 Notice from One Party to the Other.  All notices  required or permitted
hereunder  shall be in  writing  and  shall be deemed  duly  served if mailed by
certified  mail,  postage  prepaid,  addressed,  if to Tenant,  at the  Original
Address of Tenant or such other address as Tenant shall have last  designated by
notice in writing to Landlord  and, if to Landlord,  at the Original  Address of
Landlord or such other address as Landlord shall have last  designated by notice
in writing to Tenant. If requested, Tenant shall send copies of all such notices
in like manner to Landlord's mortgagees and any other persons having an interest
in the Premises and  designated  by Landlord.  Any notice so addressed  shall be
deemed duly served on the second business day following the day of mailing if so
mailed by registered or certified mail, return receipt requested, whether or not
accepted.

     8.2 Quiet Enjoyment. Landlord agrees that upon Tenant's paying all rent and
performing and observing all covenants,  conditions and other  provisions on its
part to be performed and observed,  Tenant may peaceably and quietly have,  hold
and enjoy the Premises during the Term without disturbance by Landlord or anyone
claiming  by,  through or under it,  subject  always to the terms of this Lease,
provisions  of law, and rights or interests of record to which this Lease may be
or become subject and subordinate.


                                      -34-


     8.3 Limitation of Landlord's  Liability.  Landlord shall be liable only for
breaches of Landlord's  obligations occurring while Landlord is owner of the fee
of which the Premises are a part provided,  however, that if Landlord shall ever
sell and lease-back such fee, or the ground thereof or the improvements thereon,
then "fee" shall, in such event, be deemed to mean Landlord's leasehold interest
and  provided  further  that as to claims made by Tenant  prior to a sale of the
property of which the Premises are a part,  the "fee" shall include the proceeds
from a sale of the property . Tenant (and all persons  claiming  by,  through or
under Tenant) agrees to look solely to Landlord's  interest from time to time in
the fee of which  the  Premises  are a part  for  satisfaction  of any  claim or
recovery of any judgment from  Landlord;  it being agreed that neither  Landlord
nor any trustee, beneficiary,  partner, agent or employee of Landlord shall ever
be personally or individually liable for any claim or judgment, or otherwise, to
Tenant (or such  persons).  In no event shall  Landlord ever be liable to Tenant
(or such persons) for indirect or consequential damages; nor shall Landlord ever
be answerable or liable in any equitable judicial proceeding or order beyond the
extent of its interest in the fee of which the Premises are a part.

     8.4 Excusable  Delay.  In any case where either party hereto is required to
do any act (other than the payment of Annual Fixed Rent,  additional rent or any
other sum or charge,  including without  limitation  ascertaining the dates when
such rental  payments are payable),  including the completion of Landlord's Work
and Landlord's  obligations to rebuild under Sections 6.3 and 6.4, delays caused
by or resulting from war, civil commotion,  fire, flood or other casualty, labor
difficulties,  shortages or other unavailability of labor, materials, equipment,
energy or utility  services,  unusually  severe  weather,  or other like  causes
beyond such party's  reasonable  control shall not be counted in determining the
time  during  which such act shall be  completed,  whether  such time be a fixed
date, a fixed time or "a  reasonable  time," and such time shall be deemed to be
extended by the period of such delay  except to the extent  otherwise  permitted
under  this  Lease.  This  Section  8.4  shall  not  affect  Tenant's  right  of
termination contained in Section 2.3.

     8.5  Applicable  Law  and  Construction.  This  Lease  may be  executed  in
counterpart copies and shall be governed by and construed as a sealed instrument
in  accordance  with  the  laws of The  Commonwealth  of  Massachusetts.  If any
provision shall to any extent be invalid,  the remainder of this Lease shall not
be affected.  Other than  contemporaneous  instruments executed and delivered of
even date, if any, this Lease  contains all of the agreements  between  Landlord
and Tenant  with  respect to the  Premises  and  supersedes  all prior  dealings
between them with respect thereto. There are no oral agreements between Landlord
and Tenant affecting this Lease. This Lease may be amended only by an instrument
in writing executed by Landlord and Tenant. The enumeration of specific examples
of a general  provision  shall not be construed  as a limitation  of the general
provision.  Unless a party's approval or consent is required by its terms not to
be


                                      -35-


unreasonably  withheld,  such approval or consent may be withheld in the party's
sole  discretion.  If Tenant is granted any  extension  or other  option,  to be
effective the exercise (and notice thereof) shall be unconditional,  time always
being of the essence to any options;  and if Tenant  purports to  condition  the
exercise of any option or vary its terms in any manner,  then the option granted
will  automatically  and  immediately  become  null and  void and the  purported
exercise will be  ineffective.  This Lease and all  consents,  notices and other
related  instruments may be reproduced by any party by photographic,  microfilm,
microfiche  or other  reproduction  process  and the  originals  thereof  may be
destroyed;  and each party  agrees  that  reproductions  will be  admissible  in
evidence  to the  same  extent  as  the  original  itself  in  and  judicial  or
administrative  proceeding  (whether  or not the  original is in  existence  and
whether or not  reproduction  was made in the regular  course of business),  and
further  reproduction  will  likewise be  admissible.  The titles of the several
Articles and Sections are for  convenience  only,  and shall not be considered a
part hereof.  The submission of a form of this Lease or any summary of its terms
shall not constitute an offer by Landlord to Tenant;  but a leasehold shall only
be created and the parties  bound when this Lease is executed  and  delivered by
both Landlord and Tenant.

     8.6  Successors  and  Assigns.  Except as herein  provided  otherwise,  the
agreements and conditions in this Lease  contained on the part of Landlord to be
performed   and  observed   shall  be  binding  upon   Landlord  and  its  legal
representatives,  successors  and  assigns,  and shall  inure to the  benefit of
Tenant and its legal representatives, successors and assigns; and the agreements
and  conditions  on the part of Tenant to be  performed  and  observed  shall be
binding  upon  Tenant  (and  any   guarantor  of  Tenant)  and  Tenant's   legal
representatives,  successors  and  assigns  and shall  inure to the  benefit  of
Landlord and its legal representatives, successors and assigns.

     8.7  Relationship  of the  Parties.  Nothing  herein  shall be construed as
creating the relationship between Landlord and Tenant of principal and agent, or
of partners or joint venturers;  it being understood and agreed that neither the
manner of fixing rent, nor any other provision of this Lease, nor any act of the
parties, shall ever be deemed to create any relationship between them other than
the relationship of landlord and tenant.

     8.8  Estoppel  Certificate.  Within  two weeks of either  party's  request,
Landlord and Tenant agree,  in favor of the other,  to execute,  acknowledge and
deliver a statement in writing  certifying  that this Lease is unmodified and in
full force and effect (or, if there have been any modifications that the same is
in full force and effect as modified  and stating  the  modifications),  and the
amount and dates to which the Annual  Fixed  Rent (and  additional  rent and all
other charges) have been paid and any other  information  reasonably  requested.
Both parties  intend and agree that any such statement may be relied upon by any
prospective purchaser, mortgagee, or other person to whom the same is delivered.
If Tenant  fails to provide  such a  statement  within the time period set forth
above, Tenant


                                      -36-

hereby irrevocably appoints Landlord as Tenant's attorney-in-fact,  in its name,
place and stead to do so.

     8.9 Notice of Lease.  Neither party shall record this Lease, but each party
will, upon request of the other,  execute a recordable notice of lease in a form
reasonably  approved by Landlord and, upon  termination for whatever  reason,  a
like notice of termination of lease; and Tenant irrevocably appoints Landlord as
its attorney-in-fact,  with full power of substitution,  to execute, acknowledge
and deliver a notice of termination  of lease in Tenant's name,  place and stead
if Tenant fails so to do with five (5) days of any request, provided that Tenant
is no longer occupying the Premises.

     8.10 Landlord and Tenant as Business  Entities.  If Landlord and Tenant are
business  entities,  each warrants and represents that (a) it is duly organized,
validly  existing and in good  standing  under the laws of the  jurisdiction  in
which it was organized;  (b) it has duly executed and delivered this Lease;  (c)
its execution, delivery and performance of this Lease (i) are within its powers,
and (ii) have been duly authorized by all requisite action; and (d) the Lease is
a valid and binding  obligation  upon it in accordance  with the terms set forth
therein.  This warranty and representation  shall survive the termination of the
Term.


                                   ARTICLE IX
                                   ----------

                                     Brokers
                                     -------

     9.1 Brokers.  Tenant and Landlord each represents and warrants to the other
that it has not dealt  with any  broker  (other  than  Landlord's  Agent and the
person  identified as the Broker in Section 1.1, if any) in connection with this
Lease or the Premises and each agrees to indemnify  and save the other  harmless
from all loss, claim, damage, cost or expense (including  reasonable  attorneys'
fees of counsel of the indemnitee's  choice against whom the indemnitor makes no
reasonable  objection)  arising  from  any  breach  of this  representation  and
warranty.  This warranty and representation  shall survive the term or any early
termination  of  this  Lease.  The  fees  of  Landlord's  Agent  will be paid by
Landlord. Any commission payable to the Broker shall be paid by Tenant.

                                      -37-



                                    ARTICLE X
                                    ---------

                              Landlord's Financing
                              --------------------

     10.1 Subordination and Superiority of Lease.  Tenant agrees that this Lease
and the  rights of Tenant  hereunder  will be  subject  and  subordinate  to the
present or future lien of any first mortgage,  (and at Landlord's  election,  to
the lien of any  subordinate  mortgage  or  mortgages)  and to the rights of any
lessor  under any ground or  improvements  lease of the  Premises  (collectively
referred to in this Lease as a "mortgage"  and the holder or lessor thereof from
time to time as a "mortgagee"),  and to all advances and interest thereunder and
all modifications,  renewals,  extensions and consolidations  thereof;  provided
however, that with respect to future liens, the mortgagee of any mortgage or the
holder  of any  ground or  improvement  lease  hereafter  granted  executes  and
delivers to Tenant an agreement in which the mortgagee  agrees that Tenant shall
not be disturbed in its possession upon Tenant's attornment to such mortgagee as
Landlord and performance of its Lease covenants (both of which conditions Tenant
agrees with all mortgagees to perform).  Tenant agrees that any mortgagee may at
its  option  unilaterally  elect  to  subordinate,  in  whole  or in part and by
instrument in form and substance  satisfactory to such mortgagee alone, the lien
of its mortgage (or the priority of its ground lease) to some or all  provisions
of this  Lease.  Landlord  shall use  reasonable  efforts  to obtain an  amended
nondisturbance  and attornment  agreement from Landlord's  existing mortgagee on
such  mortgagee's  customary  form and shall request such a  nondisturbance  and
attornment  agreement within 30 days after executing this Lease.  Landlord shall
use good faith efforts to obtain a nondisturbance and attornment  agreement from
any future mortgagee of Landlord on such mortgagee's customary form.

     Tenant agrees that this Lease shall survive the merger of estates of ground
(or  improvements)  lessor and  lessee.  Until a mortgagee  (either  superior or
subordinate  to this  Lease)  forecloses  Landlord's  equity of  redemption  (or
terminates in the case of a ground or improvements lease), no mortgagee shall be
liable for failure to perform any of Landlord's  obligations (and such mortgagee
shall  thereafter  be liable  only  after it  succeeds  to and holds  Landlord's
interest and then only as limited  herein).  No mortgagee  shall be bound by any
payment of rent more than one month in advance.  Tenant  shall,  if requested by
Landlord or any  mortgagee,  give notice of any alleged  non-performance  on the
part of Landlord to any such  mortgagee;  and Tenant agrees that such  mortgagee
shall have a  separate,  consecutive  reasonable  cure period of no less than 30
days (to be reasonably extended in the same manner Landlord's 30 day cure period
is to be extended) or more than 60 days following  Landlord's cure period during
which such  mortgagee may, but need not, cure any  non-performance  by Landlord.
The  agreements  in this  Lease  with  respect  to the  rights  and  powers of a
mortgagee  constitute a continuing  offer to any person which may be accepted by
taking a  mortgage  (or  entering  into a ground or  improvements  lease) of the
Premises.


                                      -38-


     10.2 Rent  Assignment.  If from time to time Landlord assigns this Lease or
the  rents  payable  hereunder  to  any  person,   whether  such  assignment  is
conditional  in  nature or  otherwise,  such  assignment  shall not be deemed an
assumption  by the assignee of any  obligations  of  Landlord;  but the assignee
shall be responsible only for  non-performance  of Landlord's  obligations which
occur after it succeeds  to and only while it holds  Landlord's  interest in the
Premises.

     10.3  Other   Instruments.   The   provisions  of  this  Article  shall  be
self-operative;  nevertheless, Tenant agrees to execute, acknowledge and deliver
any  subordination,  attornment  or  priority  agreements  or other  instruments
conforming to the provisions of this Article (and being  otherwise  commercially
reasonable)  from  time  to time  requested  by  Landlord  or any  mortgagee  in
furtherance  of the  foregoing,  and  further  agrees  that its failure to do so
within 20 days after  written  demand shall be subject to the  monetary  default
provisions of this Lease.

     WITNESS  the  execution  hereof  under  seal as of the date first set forth
above.

                                     TENANT:

                                     Interneuron Pharmaceuticals, Inc.


                                     By:       /s/ Glenn L. Cooper
                                        ----------------------------------------
                                              President


                                     By:        /s/ Thomas F. Farb
                                        ----------------------------------------
                                              Treasurer


                                    LANDLORD:

                                    Ledgemont Realty Trust


                                    By:        /s/ Robert L. Beal
                                       -----------------------------------------
                                             Trustee, but not individually



                                      -39-