Exhibit 10.4

                                 LEASE


     This LEASE AGREEMENT is entered into  as of the 30th day of  August,
     1991, by and between WESTERN ATLAS INTERNATIONAL, INC.  (hereinafter
     referred to  as ("Landlord"), whose  principal address for  purposes
     hereof is 10205 Westheimer, Houston, Texas 77042, (mailing  address:
     P. 0. Box 1407,  Houston, Texas 77251-1407, Attn: General  Counsel),
     and  CARRINGTON LABORATORIES,  INC.,  (hereinafter  referred  to  as
     "Tenant"),  whose principal  address  for purposes  hereof  is  2001
     Wa1nut Hill Lane, Irving, Texas 75038.

          (1)  DEFINITIONS.

          (a)  "Area":  The leased  area within  the Leased  Premises  is
     approximately 21,733 square feet

          (b)  Deleted intentionally.

          (c)  Deleted intentionally.

          (d) "Building": The  office  building  located  on  land   more
     particularly described  on Exhibit "C"  attached hereto  and made  a
     part hereof for  all purposes, which building  is known as the  Core
     Laboratories Building,  having a Post  Office address  of 1300  East
     Rochelle Boulevard, Irving, Texas 75062-3963.

          (e) "Commencement Date": January 1, 1992.


          (i)  Deleted intentionally.


          (g)  "Leased Premises":  The area on  Level A-1  of Building  A
     shown cross-hatched  on the floor  plan attached  hereto as  Exhibit
     "A" and made a part hereof.

          (h)  "Lease  Term": The period  commencing on  January 1,  1994
     and  ending  on  December  31,  1995  unless  sooner  terminated  as
     provided herein.

          (i)  "Lease Year"  shall mean January 1,  1992 to December  31.
     1992,  and  each  subsequent  twelve  (12)  month  period  of   time
     thereafter.

          (j)  De1eted intentionally.

          (k) "Minimum Rent": $18,110.83 per month commencing on  January
     1, 1994 and  continuing  on  or before  the first  day of each month
     of the  term hereof  through  December 31, 1993  and $20,374.69  per
     month commencing on January 1, 1994 and continuing  on or before the
     first day  of each  month of the term  hereof through the balance of
     the term of this Lease.

          (1)  "Operating Costs":    See Paragraph 8 of this Lease
<PAGE>
          (m)   "Overtime   Charge":   $50.00   per   hour   subject   to
     proportionate adjustments determined by Landlord to reflect  changes
     in labor and utility costs.

           (n) "Permitted  use":   Business offices  and laboratory  used
     for analytical chemistry in connection with medical research,  which
     shall not involve research with micro-organisms or toxins.

         (o)   Deleted intentionally.

         (p)   Deleted intentionally

         (i)   Deleted intentionally

       2. LEASE GRANT- Landlord, in consideration of the rent to be  paid
  and  to be paid  and the covenants  and agreements to  be performed  by
  Tenant, as  herein set forth, does hereby  Lease, Demise, and Let  unto
  Tenant and Tenant accepts the Leased Premises for the Lease Term.

       3(a).  RENT. Beginning on the  Commencement Date, as  hereinbefore
  defined, Tenant  promises and agrees to  pay Landlord the Minimum  Rent
  (subject to adjustment  as hereinafter provided) without demand or  any
  deduction  or  set  off  whatsoever,  for  each  month  of  the  entire
  contemporaneously with the execution of this lease, and a like  monthly
  installment shall be due and payable beginning on the first day of  the
  calendar  month next following  the expiration of  the Lease Term.  One
  such monthly installment shall  be payable by tenant to Landlord  first
  full calendar month of  the tease term after the Commencement Date  and
  continuing  thereafter on or  before the first  day of each  succeeding
  calendar month  during the term hereof.  Rent for any fractional  month
  at  the beginning of  the tease  term shall  be prorated  based on  one
  three hundred sixty-fifth (1/365th) of the current annual Minimum  Rent
  for each day of the partial month this Lease is in effect and shall  be
  due and payable on the Commencement Date.

       (b) LATE  CHARGES. In  the event  any monthly  installment of  the
  Minimum Rent,  or  any other  sums  which  become owing  by  tenant  to
  landlord under the provisions hereof are  not received within ten  (10)
  days after the due date thereof (without in any way implying Landlord's
  consent to such late payment), Tenant, to the extent permitted by  law,
  agrees to pay, in addition to  said installment of the Minimum Rent  or
  such other sums owed, a late payment charge equal to ten percent  (10%)
  of the  installment  of the  Minimum  Rent  or such  other  sums  owed.
  Notwithstanding the  foregoing, the  foregoing late  charges shall  not
  apply to any sums which  may have been advanced  by Landlord to or  for
  the benefit of  Tenant pursuant  to the  provisions of  this Lease,  it
  being understood  that  such sums  shall  bear interest,  which  Tenant
  hereby agrees to pay to Landlord, at the rate of eighteen percent (18%)
  per annum or at  the maximum rate  of interest permitted  by law to  be
  charged Tenant for the use or  forbearance of such money, whichever  is
  the lesser sum.

       4.   Deleted intentionally.
<PAGE>
       5.   SERVICES  BY  LANDLORD.  Landlord   agrees  to  furnish   the
  following services for the Leased Premises: (i) air conditioning,  both
  heating and cooling (as required by the seasons), from 10 a.m. to  6:00
  p.m. on weekdays and on Saturdays  from 8:00 a.m. to 1:00 p.m.  (except
  on legal holidays designated in the Building Rules and Regulations) and
  at such temperatures  and in  such amounts as  may in  the judgment  of
  Landlord be required  for comfortable  use and  occupancy under  normal
  business  operations;  provided,  that  circulating  air  will  not  be
  available other than by  air conditioning and  if tenant shall  require
  air conditioning at any  time other than the  hours and the days  above
  specified. Landlord  shall  furnish the  same  for the  area  or  areas
  specified  in   a  written   request  of   Tenant  delivered   to   the
  superintendent of the  Building before 3:00  p.m. of  the business  day
  preceding the  extra  usage, and  for  such service  tenant  shall  pay
  Landlord the Overtime Charge  as additional rent  within five (5)  days
  after receipt  of a  bill therefore;  (ii) water  at points  of  supply
  provided for general use of tenants of the Building: (iii) janitor  and
  maid service to the Leased Premises on weekdays other than holidays and
  such window  washing  and wall  cleaning  as  may in  the  judgment  of
  Landlord be  reasonably required;  provided, however,  that Tenant  may
  elect to  supply Tenant's  own janitorial  and maid  service by  giving
  Landlord thirty (30) days  prior written notice  and in such an  event,
  tenant will  be  granted a  monthly  credit against  the  Minimum  Rent
  payable under  the terms  of Paragraph  1(k) hereof  equivalent to  the
  Tenant's prorata  share  of  the costs  Landlord  is  paying  for  such
  cervices on a monthly basis as of the date of this lease. Which prorata
  share shall  be  that  proportion of  Landlord's  costs  determined  by
  multiplying such costs  by a fraction,  the numerator of  which is  the
  square footage of the Leased Premises  and the denominator of which  is
  the total square footage of the Building covered by Landlord's contract
  for such services' provided further, however, that Tenant shall receive
  the foregoing credit only so long as the level of set-vice is equal  to
  or exceeds the level  of service which would  have been provided  under
  Landlord's contract as reasonably determined by Landlord; (iv) restroom
  facilities; (v)  electric lighting  for all  public areas  and  special
  service areas of the Building in the manner and to the extent deemed by
  Landlord  to  be  reasonable  and  standard  including  replacement  of
  Buildings standard light bulbs  and tubes; and (vi) a twenty-four  (24)
  hour monitored security system similar or comparable to that  presently
  maintained.

       6.  (a) TENANT'S  ELECTRICITY CHARGE  . Landlord  shall,  provided
  Tenant is not in default of  its obligations under this Lease,  furnish
  sufficient power  for  lighting  and for  typewriters,  voice  writers,
  calculating machines, and other standard office machines of similar low
  electrical consumption  width  use  Voltage  of  110  volts  or  lower.
  Landlord will  provide  power  as required  by  tenant  for  laboratory
  equipment which  requires up  to 240  volts through  the then  existing
  feeders servicing  the Building  and will  bill Tenant  for its  excess
  electricity  requirements  as  set  forth  below.  If  Tenant  has  any
  equipment or  machines  that  require  excess  counts  of  electricity,
  Landlord reserves  the right,  at its  sole option  except as  provided
  hereinafter, to install a separate meter(s), at tenant's expense, to be
  reimbursed to Landlord as additional rent  upon demand. For the  Leased
  Premises or any part or parts thereof. If tenant has excess electricity
  requirements for  which Landlord  does not  elect to  install  separate
  meter(s), Landlord's  engineer  may, but  shall  not be  obligated  to,
  determine the amount of  excess electricity to  be allocated to  Tenant
<PAGE>
  based on the  power requirements of  any such  equipment, machines,  or
  special lighting. If  Tenant does  not agree  with the  amount of  such
  allocation, tenant may require  Landlord to exercise Landlord's  option
  to install separate meter(s) by giving written notice to Landlord.  All
  installations of electrical fixtures, appliances, and equipment  within
  the Leased  Premises  shall  be subject  to  Landlord's  prior  written
  approval.  All  replacements  lighting  tubes  and  bulbs  required  in
  Building standard fixtures in the Leased Premises will be furnished and
  installed by Landlord at  Landlord's expense. Whenever  heat-generating
  machines or equipment (other than such standard office machines)  which
  affect the temperatures  otherwise maintained by  the air  conditioning
  system, are used in the Leased Premises by Tenant, Landlord shall  have
  the right to install supplemental air conditioning units in the  Leased
  Premises, and the  cost thereof,  including the  cost of  installation,
  operation, use and  maintenance, shall be  paid as  additional rent  by
  tenant to Landlord on demand. Tenant  covenants and agrees that at  all
  times its use of  electric current shall never  exceed the capacity  of
  existing  feeders   to  the   building,  or   the  risers   or   wiring
  installations. Any riser or  risers or wiring  to meet Tenant's  excess
  electrical requirements  will be  installed  by Landlord  upon  written
  request of  tenant,  at the  sole  cost and  expense  of tenant  to  he
  reimbursed  to  Landlord  an  additional  rent  upon  demand,  if,   in
  Landlord's sole  judgment the  same are  necessary and  will not  cause
  permanent damage or injury  to the building or  the Leased Premises  or
  cause or create a dangerous or hazardous condition or entail  excessive
  or unreasonable alterations,  repairs or expense  or interfere with  or
  disturb other tenants or occupants.

       Notwithstanding anything to  the contrary hereinbefore  contained,
  it is understood  and agreed that  electricity consumed  in the  Leased
  Premises other than  electricity for the  heating, ventilating and  air
  conditioning system  is  metered  through  a  sub  meter  installed  by
  Landlord (the "Meter"). Should  Tenant's consumption of electricity  in
  the Leased Premises during any calendar month or partial calendar month
  during the term  hereof as measured  by the Meter  exceed seventy  (70)
  kilowatt hours  per day  for such  month (the  "Excess Usage"),  Tenant
  shall pay the costs of the Excess Usage to Landlord as Additional  Rent
  hereunder within  fifteen  (15)  days  after  Tenant  receives  a  bill
  therefor from Landlord. All such charges shall be at the same rate  for
  electricity, which  Landlord is  being charged  by the  public  utility
  serving the Building.

       (b)  Tenant's  Water  Charge.  Not withstanding  anything  to  the
  contrary contained  in this  lease, it  is understood  and agreed  that
  water consumed  in the  Leased Premises  other  than for  drinking  and
  restrooms is  metered through  a submeter  installed by  landlord  (the
  "Water Meter"). Tenant shall  pay Landlord the costs  of such water  as
  Additional Rent  hereunder based  on actual  usage as  measured by  the
  water Meter at a cost equal to the actual charges therefor to  Landlord
  by the  local  water utility  within  fifteen (15)  days  after  Tenant
  receives a bill therefor from Landlord.
<PAGE>
       7.  Service  Interruptions. Landlord  does  not warrant  that  the
  services provided  for in Paragraphs 5  and 6 above  will be free  from
  any   slow-down,  interruption  or   stoppage  pursuant  to   voluntary
  agreement  by   and  between  Landlord  and  governmental  bodies   and
  regulatory   agencies   or   caused   by   the   maintenance,   repair,
  substitution,  renewal,  replacement, or  improvement  of  any  of  the
  equipment involved in the furnishing of any such services or caused  by
  changes   of   services,   alterations,   strikes,   lock-outs,   labor
  controversies, fuel shortages, accidents acts of God, the elements,  or
  any  other  cause  beyond  the  reasonable  control  of  Landlord,  and
  specifically no such  slow-down, interruption, or stoppage of any  such
  services   shall  ever  be   construed  as  an   eviction,  actual   or
  constructive,  of Tenant  nor shall  same cause  any abatement  of  the
  Minimum  Rent payable hereunder  or in any  manner or  for any  purpose
  relieve Tenant from any  of its obligations hereunder, and in no  event
  shall  Landlord he  liable for  damage to  persons or  property, or  in
  default  hereunder, as  a result  of such  slow-down, interruption,  or
  stoppage. Landlord  agrees to use due  diligence to resume the  service
  upon any such slow-down, interruption, or stoppage.

        8. Operating Costs. Operating Costs (as hereinafter defined)  for
  1992 (the "Base Year") shall be calculated by Landlord. Landlord  shall
  split the Base Year Operating Costs into two parts, the first of  which
  shall consist of  taxes, special real  estate assessments,  electricity
  and other utility costs,  and insurance premiums (hereinafter  referred
  to as "Unrestricted Items")  and the second of  which shall consist  of
  all other  Operating  Costs  (hereinafter referred  to  as  "Restricted
  Items"). Operating Costs per square foot  shall be calculated for  both
  Unrestricted Items and  Restricted Items by  dividing the  Unrestricted
  Items and Restricted Items by the total square footage of the  Building
  (i.e. approximately  205.893 square  feet).  Such Operating  Costs  per
  square foot shall be the "Base Year Operating Costs". Tenant shall  pay
  Landlord for each  calendar year or  partial calendar  year during  the
  term hereof  increases  in the  Operating  Costs per  square  foot  for
  Unrestricted Items and  Restricted Items over  the Base Year  Operating
  Costs (hereinafter referred  to as "Excess  Operating Costs") for  each
  square foot of  the leased Premises  (i.e. approximately 21,733  square
  feet): provided, however, that the Operating Costs per square foot  for
  Restricted Items may not for the purposes hereof increase by more  than
  five percent (5%) per calendar year on a compounded cumulative basis.

        The term "Operating Costs" as used herein shall mean and  include
  all expenses (other than expenses for electricity covered by the  terms
  of Paragraph 6(a) hereof  and water covered by  the terms of  Paragraph
  6(b) hereof) reasonably and directly incurred in the normal management,
  operating, maintenance, repair and security of the Building,  including
  the grounds. Operating Costs shall include, but not be limited to,  the
  cost of all utilities (except expenses  for electricity covered by  the
  terms of  Paragraph 6(a)  hereof  and water  covered  by the  terms  of
  Paragraph 6(b) hereof), building  supplies, janitorial service  (except
  if Tenant  elects  to provide  its  own janitorial  and  maid  service,
  janitorial and  maid service  for any  period of  time when  Tenant  is
  supplying such service shall not be  included under Operating Costs  to
  the extent such charges apply to occupied Tenant space in the  Building
  as opposed  to common  use areas),  maintenance and  repairs, fire  and
  extended coverage, public liability and other insurance, all labor  and
  employee benefit  costs  (including wages,  salaries  and fees  of  all
  personnel engaged in the management, operating, maintenance, repair and
<PAGE>
  security of  the  Building),  ad  valorem  taxes  and  assessments  and
  amortization of  capital  improvements  costs  which  reduce  operating
  expenses or are required  to meet governmental regulations,  management
  fees, consulting fees,  legal fees and  accounting fees,  and the  fair
  market rental  of  the  property managers'  offices  in  the  Building,
  together with payments or  credits Landlord may make  to any tenant  or
  tenants of  the Building  in  lieu of  Landlord  providing any  of  the
  services or paying for any of such costs.

       In  addition to Tenant's obligations  to pay Minimum Rent,  Tenant
   shall pay to  Landlord monthly in advance on  or before the first  day
   in each calendar month  during the term hereof, commencing on  January
   1,  1992, one  twelfth  (1/12th)  of Landlord's estimate  of  tenant's
   proportionate  share of  Excess  Operating Costs  for  the  applicable
   calendar year. Landlord reserves  the right to adjust the estimate  at
   any  time  during  the  applicable  calendar  year  if  actual  Excess
   Operating  Costs   are  substantially  different   from  the   earlier
   estimate,  and  thereafter,  payments  by  Tenant  pursuant  to   this
   paragraph shall be adjusted accordingly, For the purposes hereof,  the
   terms "calendar year" shall also include partial calendar years.

       After the expiration of each calendar year during the term  hereof
   after  the  Base  Year,   as  hereinbefore  defined,   Landlord  shall
   furnish Tenant with a  statement of the actual Excess Operating  Costs
   of the Building. In the event  the sum of the payments made by  Tenant
   during the preceding  calendar year or partial calendar year  pursuant
   to  the foregoing  exceeds the  amount which  Tenant would  have  been
   obligated to pay  if the actual Excess  Operating Costs for such  year
   were  used in  lieu of  Landlord's  estimate thereof,  the  difference
   shall be  credited by Landlord  to Tenant's account  against the  next
   payments due by Tenant under  the provisions hereof. In the event  the
   sum of payments made by  Tenant during the preceding calendar year  or
   partial calendar  year pursuant to  the above paragraph  is less  than
   the  amount which  Tenant would  have  been obligated  to pay  if  the
   actual Excess Operating Costs for such year or partial year were  used
   in lieu  of Landlord's estimate thereof,  Tenant shall pay the  amount
   of such difference to Landlord  in cash within thirty (30) days  after
   delivery  of  any  invoice for  such  by  Landlord  accompanied  by  a
   statement of  the actual  Excess Operating  Costs for  such year.  Any
   payments  by Tenant  which exceed  Tenant's  prorate share  of  Excess
   Operating  Costs for  such period  shall be  refunded by  Landlord  to
   Tenant.

       9.   ACCEPTANCE OF  LEASED PREMISES  AND BUILDING  BY TENANT.  The
   taking  of  possession of  the  Leased  Premises by  Tenant  shall  be
   conclusive evidence  that "Tenant"  accepts the  Leased Premises,  the
   Building and  all improvements and  appurtenances thereto as  suitable
   for the purposes  herein set out as being  in a good and  satisfactory
   condition.
<PAGE>
       10.  ASSIGNMENT AND SUBLETTTNC. (a) Tenant shall not, without  any
   prior  written  consent of  Landlord:  (i)  assign or  in  any  manner
   transfer this lease or any estate or interest therein; or (ii)  permit
   any assignment  of this  lease or any  estate or  interest therein  by
   operation of  law; or  (iii) sublet the  Leased Premises  or any  part
   thereof; or  (iv) grant  any license,  concession, or  other right  of
   occupancy of  any portion of  the Leased Premises;  or (v) permit  the
   use  of the  Leased Premises  by any  parties other  than Tenant,  its
   agents and  employees. Landlord agrees  that its consent  will not  be
   unreasonably withheld or  delayed with respect to a proposed  sublease
   or assignment  so long  as any  such proposed  sublease or  assignment
   meets the following criteria:

          (i)       The use contemplated  by such sublease or  assignment
                    is in accordance with the terms of this lease and  is
                    for an office  purpose which is  consistent with  the
                    image  of  Building   as  reasonably  determined   by
                    Landlord; and

          (ii)      The proposed sublessee  or assignee  will not  engage
                    in   operations   which   violate   any   restrictive
                    covenant affecting the Building; and

          (iii)     The proposed sublease  or assignment is made  subject
                    to this lease; and

          (iv)      No option provided  for in this  lease will inure  to
                    the benefit of any such sublessee or assignee; and

          (v)       A full and complete copy of the proposed sublease  or
                    assignment, together  with  a statement  from  Tenant
                    outlining  the  financial   terms  of  the   proposed
                    sublease or assignment will be provided to  Landlord;
                    and

          (vi)      The proposed sublessee  or assignee will occupy  that
                    portion  of  the  Leased  Premises  covered  by  such
                    sublease or assignment; and

         (vii)       The proposed sublessee or assignee is a  financially
                     responsible  entity  as  reasonably  determined   by
                     Landlord.

     Consent by Landlord to one or more assignments or sublettings  shall
     not  operate as a waiver of Landlord's  rights as to any  subsequent
     assignments  and  sublettings.  Notwithstanding  any  assignment  or
     subletting, Tenant  and any guarantor of Tenant's obligations  under
     this  lease shall at all times  remain jointly and severally  liable
     for  the  payment of  the rent  and  all other  payment  obligations
     herein  specified and  for  compliance with  all of  Tenant's  other
     obligations   under  this  lease.  If   an  event  of  default,   as
     hereinafter defined,  should occur while the Leased Premises or  any
     part thereof  are then assigned or sublet, Landlord, in addition  to
     any  other remedies herein provided or provided  by law, fly at  its
     option  collect directly from such  assignee or sublessee all  rents
     becoming due  to Tenant under such assignment or sublease and  apply
     such rent against any sums due to Landlord by Tenant hereunder,  and
<PAGE>
     Tenant hereby authorizes and directs any such assignee or  sublessee
     to  make such payments of  rent direct to  Landlord upon receipt  of
     notice  from Landlord.  No direct  collection by  Landlord from  any
     such  assignee  or sublessee  shall  be construed  to  constitute  a
     novation or a release of tenant or any guarantor of Tenant from  the
     further  performance  of  their obligations  hereunder.  Receipt  by
     Landlord  of rent from any assignee,  sublessee, or occupant of  the
     Leased  Premises shall not  be deemed a  waiver of  the covenant  in
     this lease contained against assignment and subletting or a  release
     of  Tenant  or any  guarantor  of Tenant's  obligations  under  this
     lease. the  receipt by Landlord from any such assignee or  sublessee
     obligated  to make payments  of rent shall  be a  full and  complete
     release,  discharge, and acquittance to  such assignee or  sublessee
     to  the fltent  of any  such amount  of rent  so paid  to  landlord.
     Landlord  is  authorized and  empowered,  on behalf  of  Tenant,  to
     endorse  the  name  of  Tenant  upon  any  check,  draft,  or  other
     instrument  payable to  Tenant evidencing  payment of  rent, or  any
     part  thereof, and to  receive and apply  the proceeds therefrom  in
     accordance  with  the  terms thereof.  Tenant  shall  not  mortgage,
     pledge, or  otherwise encumber its interest in this lease or in  the
     teased Premises.

           (b)  If Tenant  requests Landlord's consent  to an  assignment
     of the lease or subletting of all or a part of the Leased  Premises,
     it  shall submit to Landlord, in writing,  the name of the  proposed
     assignee  or subtenant and the nature and character of the  business
     of  the proposed  assignee  or subtenant.  Landlord shall  have  the
     option,  to be exercised within thirty (30) days from submission  of
     Tenant's  written request, to cancel  this lease (or the  applicable
     portion  thereof as to a partial subletting) as of the  commencement
     date  stated in the above-mentioned  request. If Landlord elects  to
     cancel  this lease as stated  then the term of  this lease, and  the
     tenancy  and occupancy of the Leased Premises by Tenant  thereunder,
     shall  cease,  determine, expire,  and  come to  an  end as  if  the
     cancellation  date was the original termination date of this  lease.
     If  Landlord does not thus cancel this  lease and if the request  of
     Tenant  to sublet or assign is  in accordance with Subparagraph  (a)
     hereof, landlord will consent to such subletting or assignment.

           (c) Landlord  shall have  the right  to transfer,  assign,  or
     convey, in  whole or in part, the Building and the Land and any  and
     all  of its  rights under  this  lease, and  in the  event  Landlord
     transfers, assigns, or conveys its rights under his lease,  Landlord
     shall  thereby be released  from any  further obligations  hereunder
     and  Tenant agrees to look solely to  such successor in interest  of
     the Landlord for performance of such obligations.

           11.  (a) USE  AND  OCCUPANCY. Tenant  agrees that  the  Leased
     Premises  shall  be  used  and  occupied  by  Tenant  only  for  the
     Permitted  Use and for no  other purpose, and  Tenant agrees to  use
     and  maintain the  leased Premises in  a clean,  careful, safe,  and
     proper  manner and to  comply with all  applicable laws  ordinances,
     orders,  rules, and regulations of  all governmental bodies  (state,
     federal,  and municipal). Tenant  will not in  any manner deface  or
     injure the Building or the land or any part thereof or overload  the
     floors  of the Leased Premises.  Tenant agrees not  to use or  allow
     or  permit  the  Leased  Premises   to  be  used  for  any   purpose
     prohibited by law or by any restrictive covenants applicable to  the
<PAGE>
     Building  and land, and Tenant agrees not to commit waste or  suffer
     or  permit waste to be committed or to allow or permit any  nuisance
     on  or  in the  leased  Premises. Tenant  will  not use  the  Leased
     Premises  for lodging  or sleeping purposes  or for  any immoral  or
     illegal purposes. "Tenant" will conduct its business and occupy  the
     Leased  Premises and will control its agents, employees,  licensees,
     and  invitees in such a manner so  as not to create any nuisance  or
     interfere  with, annoy, or disturb any of  the other tenants in  the
     Building  or Landlord in its  management of the  Building and so  as
     not  to injury the reputation of the Building. Tenant shall not  use
     the  Leased Premises or allow or permit  same to be used in any  way
     or  for any purpose that landlord may deem to be extra hazardous  on
     account  of the possibility of fire or other casualty or which  will
     increase  the rate of fire  or other insurance  for the Building  or
     its  contents or  in respect  of the  operation of  the Building  or
     which  may  render  the Building  uninsurable  at  normal  rates  by
     responsible  insurance carriers  authorized to  do business  in  the
     State  of Texas or which may render  void or voidable any  insurance
     on  the Building.  Tenant shall  not erect,  place, or  allow to  be
     placed  any sign, advertising matter,  stand, booth, or showcase  in
     or  upon the doorsteps, vestibules, halls, corridors, doors,  walls,
     windows,  or  pavement of  the  Building  or the  land  (except  for
     lettering on the door or doors to the teased Premises as allowed  by
     the Rules and Regulations forming a part of this tease) without  the
     prior written consent of Landlord.

         (b)  Hazardous Substances. Tenant covenants and agrees (i)  that
    Tenant has not suffered,  permitted, introduced or maintained in,  on
    or about any  portion of the Leased  Premises since the  commencement
    of the term  of the Carrington  Lease (as defined  in Paragraph C  of
    Exhibit "D" to this  Lease), any  Hazardous Material  [as defined  in
    Section  ll(d)(i)) except  as  may  be permitted  by  law,  it  being
    understood  that  Tenant  may,   from  time  to  time,  handle   such
    substances  in  conjunction  with  Tenant's  laboratory   operations.
    Tenant further covenants  and agrees to  indemnify, protect and  save
    Landlord  harmless against  and  from  any and  all  damage,  losses,
    liabilities,  obligations, penalties,  claims,  litigation,  demands,
    defenses,  judgments, suits,  proceedings,  costs,  disbursements  or
    expenses of any kind or of any nature whatsoever (including,  without
    limitation. attorneys'  and experts'  fees and  disbursements)  which
    may at any time be iniposed upon, incurred by or asserted or  awarded
    against landlord and  arising from or out  of any Hazardous  Material
    on,  in, under  or affecting  all or  any  portion of  the  Building.
    Leased  premises,  or Property,  introduced  by,  or  on  behalf  of,
    Tenant, including, without  limitation, (i) the  costs of removal  of
    any  and all  Hazardous Materials  from all  or  any portion  of  the
    Building,  Leased Premises  or  Property,  or  released,  discharged,
    leaked or  spilled from  the Building,  teased Premises  or  Property
    into the air, surface water, groundwater or land, and (ii) any  costs
    incurred to  comply with  or as  a  result of  the violation  of  any
    Environmental Requirements  [as defined  in Section  ll(d)(ii)].  The
    preceding  portions of  this  provision  do not  apply  to  Hazardous
    Material which may  be located in the  Building, Leased Premises,  or
    Property  at  or  prior  to  the  initial  commencement  (hereto   or
    hereafter) of any work, construction, repairs or alterations  therein
    by Tenant under the Carrington Lease
<PAGE>
         (c)  Remediation.  Notwithstanding anything contained herein  to
    the  contrary,  Tenant shall  within a  period  of thirty  (30)  days
    following  the date this Lease is cancelled or terminated or  expires
    by virtue of its own terms, cause to be conducted by a duly  licensed
    environmental   consultant,  inspections  and   tests  in  order   to
    determine if any Hazardous Material [as defined in Section  ll(d)(i)]
    exists  in, on  or about  the  Leased Premises  in violation  of  any
    Environmental  Requirements  [as defined  in Section  ll(d)(ii)]  (or
    materials  ,which would constitute danger to any occupants or  guests
    in the Leased Premises or Building) and Tenant' shall (i) furnish  to
    landlord   copies  of  any   findings,  conclusions  and/or   reports
    respecting such investigations and/or tests, and (ii) be  responsible
    for  restoring the teased Premises and  Building with respect to  any
    damages  incurred incidental  thereto as  the result  of Tenant's  or
    Tenant's  agents,  employees  or  contractors  introduction  of  such
    Hazardous  Material to the Leased Premises or the Building. Any  such
    reports  shall  include a  so-called  "Phase I"  and,  if  necessary,
    "Phase  II" environmental assessments, which  shall be, addressed  to
    Tenant,  In the event any such report  indicates the presence of  any
    Hazardous  Material [as defined  in Section  ll(d)(i)] (or  materials
    which  would constitute  danger to  any occupants  or guests  in  the
    Leased  Premises or  Building), then  Tenant shall  at Tenant's  sole
    cost   and  expense  conduct  such  cleanup  operations  as  may   he
    reasonably  required to clear such Hazardous Material (as defined  in
    Section   l1(d)(i)]  from  the  Leased   Premises  and  Building   in
    accordance  with  the then  existing Environmental  Requirements  Law
    defined  in Section [l(d)(ii)]  applicable thereto  and Tenant  shall
    Indemnify,  save and hold Landlord harmless from any claims.  losses,
    damages  or  judgments  as  a result  of  the  introduction  of  such
    substances  into the Leased  Premises and  Building and/or  resulting
    because of the removal thereof.

          (d)  Definitions
               (i)  Hazardous Materials

                    Hazardous Material means any substance:   (1)     the
                    presence   of   which   requires   investigation   or
                    remediation   under  any  federal.  state  or   local
                    statute.   regulation,  ordinance,   order,   action,
                    policy  or common  law; or  (2) which  is or  becomes
                    defined   as   a   "hazardous   waste,"    "hazardous
                    substance",   pollutant  or  contaminant  under   any
                    federal,  state, or local statute, regulation,  rule,
                    or   ordinance  or   amendments  thereto   including,
                    without  limitation, the Comprehensive  Environmental
                    Response, Compensation and Liability Act (421  U.S.C.
                    Section   9601   et   seq.)   and/or   the   resource
                    Conservation  and  Recovery Act  (42  V.S.C,  Section
                    6901  et seq.);  or (3)  which is  toxic,  explosive,
                    corrosive,   flammable,   infectious,    radioactive,
                    carcinogenic,  mutagenic, or otherwise hazardous  and
                    is   or  becomes   regulated  by   the   governmental
                    authority,  agency, department, commission, board  or
                    instrumentality  of the United  States, the State  of
                    Texas  or any political  subdivision thereof: or  (4)
                    the  presence of which on the Leased Premises  causes
                    or  threatens to  cause a  nuisance upon  the  Leased
<PAGE>
                    Premises  or  to  adjacent  properties  or  poses  or
                    threatens  to pose a hazard  to the health or  safety
                    of  persons on or about  the teased Premises: or  (5)
                    without  limitation, which  contains  polychlorinated
                    biphenyls (PCBs) or asbestos.

               (ii) Environmental Requirements

                    Environmental   requirements  means  all   applicable
                    present  and  future  statutes,  regulations,  rules,
                    ordinances,   codes,   licenses,   permits,   orders,
                    approvals,   plans,   authorizations,.   concessions,
                    franchises.  and similar items,  of all  governmental
                    agencies,  departments, commissions, boards,  bureaus
                    or  instrumentalities of  the United  States,  states
                    and   political   subdivisions   thereof   and    all
                    applicable  judicial, administrative, and  regulatory
                    decrees,  judgments,  and  orders  relating  to   the
                    protection  of  human  health  or  the   environment,
                    including, without limitation: (1) all  requirements,
                    including  but  not limited  to those  pertaining  to
                    reporting, licensing, permitting, investigation,  and
                    remediation  of emissions,  discharges, releases,  or
                    threatened  releases of Hazardous Material,  chemical
                    substances,  pollutants, contaminants,  or  hazardous
                    or  toxic substances,  materials or  wastes,  whether
                    solid,  liquid or gaseous  in nature,  into the  air,
                    surface  water, groundwater, or land, or relating  to
                    the   manufacture,  processing,  distribution,   use,
                    treatment, storage, disposal, transport, or  handling
                    of chemical substances, pollutants, contaminants,  or
                    hazardous or toxic substances, materials, or  tastes,
                    whether  solid. fluid, or gaseous in nature: and  (2)
                    all requirements pertaining to the protection of  the
                    health and safety of employees or the public.

          (e) Survival  and Investigation. The  obligations of Tenant  in
     subsections 11(b), (c), (d) and (e) shall survive the  cancellation,
     expiration or termination of the Lease and shall not be affected  by
     an investigation by or on  behalf of Landlord or by any  information
     which Landlord may have or obtain with respect thereto.

          12.  TENANTS  REPAIRS AND ALTERATIONS. Tenant  will not in  any
     manner deface  or injure the  Leased Premises, the  Building or  any
     improvements on the land herein described, and will pay the cost  of
     repairing any damage or  injury done to the foregoing facilities  by
     Tenant  or Tenant's  agents,  employees or  invitees.  Tenant  shall
     throughout the Lease  Term take good care  of the premises and  keep
     them free  from waste  and nuisance of  any kind.  Tenant agrees  to
     keep the premises,  including all fixtures  installed by Tenant  and
     any plate  glass and  special store  fronts, in  good condition  and
     make all  necessary  nonstructural repairs  except those  caused  by
     fire, casualty or acts  of God covered by Landlord's tire  insurance
     policy covering  the Building,  provided that  Tenant shall  not  be
     obligated to repair  broken exterior plate  glass unless it  appears
     that such glass  was broken by an  impact originating in the  leased
     Premises. If Tenant fails  to make such repairs within fifteen  (15)
<PAGE>
     days after the occurrence of the damage or injury, Landlord may,  at
     its  option,  make  such  repair,  and  Tenant  shall,  upon  demand
     therefor, pay Landlord  for the cost thereof.  Tenant will not  make
     or allow to be made any  alterations or physical additions in or  to
     the premises  without the  prior written  consent of  Landlord.  All
     maintenance. repairs, alterations,  additions or improvements  shall
     be conducted  only  by contractors  and subcontractors  approved  in
     writing by Landlord, it  being understood that Tenant shall  procure
     and maintain,  and shall cause  such contractors and  subcontractors
     engaged  by  or  on  behalf  of  Tenant  to  procure  and  maintain,
     insurance coverage  against such  risks, in  such amounts  and  with
     such companies as landlord  may require in connection with any  such
     maintenance, repair, alteration, addition or improvement.

          13.  MECHANIC'S LEINS . Tenant  will not permit any  mechanic's
     or  materialman's  lien or  liens  to  be  placed  upon  the  Leased
     Premises, the  Building or  the lands  herein described  during  the
     term,  hereof  ceased  by  or  resulting  from  any  work  performed
     materials furnished or obligation  incurred by or at the request  of
     Tenant  and nothing  in  this Lease  contained  shall be  deemed  or
     construed in  any way  as  constituting the  consent or  request  of
     Landlord, express  or implied,  by inference  or otherwise,  to  any
     contractor,   subcontractor,  laborer,   or  materialman   for   the
     performance of any labor or the furnishing of any materials for  any
     specific improvement,  alteration, or  repair of  or to  the  Leased
     Premises  or any  part  thereof, nor  as  giving Tenant  any  right,
     power, or authority to contract  for or permit the rendering of  any
     services or the furnishing of any materials that would give rise  to
     the filing of any  mechanic's, materialman's or other liens  against
     the interest of Landlord in the Leased Premises. In the case of  the
     filing of  any lien on  the interest of  Landlord or  Tenant in  the
     Leased Premises,  Tenant shall cause  the same to  be discharged  of
     record within twenty (20) days  after the filing of same. If  Tenant
     shall fail  to discharge  such  lien within  such period,  then,  in
     addition to  any other right  or remedy of  landlord, Landlord  may.
     but shall not be obligated  to, discharge the same either by  paying
     the amount claimed to be due  or by procuring the discharge of  such
     lien by  deposit in court  or bonding. Any  amount paid by  Landlord
     for any of  the aforesaid purposes, or  for the satisfaction of  any
     other lien, not caused or claimed to be caused by Landlord, and  all
     reasonable  legal   and  other  expenses   of  Landlord,   including
     reasonable counsel  fees, in  defending  any such  action or  in  or
     about  procuring the  discharge of  such  lien, with  all  necessary
     disbursements in connection therewith, with interest thereon at  the
     rate set out in Paragraph 3(c) hereof,

          14.  INDEMNIFICATION

           (a)  Except to the extent of Landlord's negligence or  willful
      misconduct,  Tenant  agrees  to  indemnify  Landlord  and  save  it
      harmless from all  suits, actions, damages,  liability and  expense
      in connection  with loss  of  life, bodily  or personal  injury  or
      property damage (and each and all  of them) arising from or out  of
      any occurrence in, upon  or from the  Leased Premises or  resulting
      from or attributable  to the  occupancy or  use by  Tenant of  said
      Leased Premises or  any part thereof,  or occasioned  wholly or  in
      part by any  act or omission  of Tenant,  its agents,  contractors,
      employees,  servants,  invitees,   licensees  or   concessionaires.
<PAGE>
      Tenant shall store its  property in, and  shall occupy, the  Leased
      Premises at its  own risk, and  releases Landlord,  to the  fullest
      extent permitted by law,  from all claims  of every kind  resulting
      in loss of life, personal or  bodily injury or property damage,  no
      matter when or where or to  whom same occurs without being  limited
      by any other provision of this Lease.

           (b)  Landlord shall not be responsible or liable to tenant  or
     to any other person or persons for any loss or damage to either  the
     person or  property of  Tenant or to  any other  person or  persons,
     landlord shall not be responsible for any injury, loss or damage  to
     any person or to any  property of tenant or any other person  caused
     by or resulting from  bursting, breakage or from leakage, steam,  or
     snow or ice, running, backing  up, seepage or the overflow of  water
     or sewage in  any part of the teased  Premises, the building or  the
     lands herein  described, or for  any injury or  damage caused by  or
     resulting from  acts of God or  the elements, or  for any injury  or
     damage caused by or resulting  from any defect or negligence in  the
     occupancy,  construction, operation  or use  of  any of  the  Leased
     Premises, machinery, apparatus or equipment by anyone or by or  from
     the negligence of any occupant of the Building.

           15.  INSURANCE, tenant shall,  at its sole  cost and  expense,
     procure and maintain during the term hereof a policy or policies  of
     insurance insuring Tenant  against any and all liability for  injury
     to or death of a person or persons and for damage to or  destruction
     of property occasioned  by or arising out  of or in connection  with
     the use or occupancy of  the Leased Premises or by the condition  of
     the Leased Premises  (including the contractual liability of  Tenant
     to indemnify  landlord and/or property damages,  or with such  other
     limits  as may be  required by  landlord, and  to be  written by  an
     insurance  company  or   companies  satisfactory  to  landlord   and
     licensed to do  business in the State  of Texas with Landlord  named
     as  an additional  insured without  restriction.  If Tenant  has  an
     umbrella  or  excess  policy,  tenant  will  name  landlord  as   an
     additional insured without restriction on all layers of umbrella  or
     excess policies.  Tenant shall obtain  a written  obligation on  the
     part of each insurance company to notify landlord at least ten  (10)
     days prior to cancellation of such insurance. Such policies or  duly
     executed  certificates  of  insurance  relating  thereto  shall   be
     promptly  delivered to  landlord  within  ten (10)  days  after  the
     execution of  this Lease and renewals  thereof as required shall  be
     delivered  to  Landlord at  least  thirty  (30) days  prior  to  the
     expiration  of the  respective  policy  terms. If  tenant  fails  to
     comply  with  the  foregoing  requirements  relating  to  insurance,
     landlord  may  obtain  such  insurance  and  Tenant  shall  pay   as
     additional rent to landlord on demand the premium cost thereof  plus
     interest at the rate set out in Paragraph 3(c) hereof.

          16.  WAIVER  OF SUBROGATION.  Each party  hereto hereby  waives
     any and  every claim  which arises  or may  arise in  its favor  and
     against the other party hereto, or anyone claiming through or  under
     them, by way  of subrogation or otherwise,  during the term of  this
     Lease or any extension or renewal  thereof for any and all loss  of,
     or damage to, any  of its property or property  of others it has  in
     its  care, custody  or  control or  loss  of use  of  such  property
     (whether or  not such  loss or  damage  is caused  by the  fault  or
     negligence of the  other party or anyone  for whom said other  party
<PAGE>
     may be responsible),  which loss or damage  is covered by valid  and
     collectible fire  and extended coverage  insurance policies, to  the
     extent that such  loss or damage is  recovered under said  insurance
     policies.  Said  waivers  shall  be  in  addition  to,  and  not  in
     limitation or derogation of,  any other waiver or release  contained
     in this tease with respect to any loss or damage to property of  the
     parties hereto. Inasmuch as  the above mutual waivers will  preclude
     the assignment  of any  aforesaid claim  by way  of subrogation  (or
     otherwise) to  an  insurance company  (or  any other  person),  each
     party hereto  hereby agrees immediately  to give  to each  insurance
     company  which has  issued  to  it policies  of  fire  and  extended
     insurance  coverage written  notice  of  the terms  of  said  mutual
     waivers, and to have  said insurance policies properly endorsed,  it
     necessary, to prevent the  invalidation of said insurance  coverages
     by reason of said waivers.

           17.   CERTAIN RIGHTS  RESERVED BY  LANDLORD.   Landlord  shall
     have the  following rights, exercisable  without notice and  without
     liability to  tenant for damage or  injury to property, persons,  or
     business and without effecting an eviction, constructive or  actual,
     or disturbance of Tenant's use  or possession or giving rise to  any
     claim for setoff or abatement of rent:

                (a)  To change the Building's name or Street address.

                (b)  To install, affix, and  maintain any and  all  signs
           on the exterior and interior  of the Building, subject to  the
           provisions of Rider 1 of this Lease.

                (c)  To designate  and  approve, prior  to  installation,
           all types of  window shades, blinds,  drapes, awnings,  window
           ventilators,  and  similar  equipment,  and  to  control   all
           internal lighting  that nay be  visible from  the exterior  of
           the Building.

                (d) To  enter  upon  the Leased  Premises  at  reasonable
           hours to inspect same or clean or wake repairs or  alterations
           (but without  any obligation  to do  so. except  as  expressly
           provided  for herein)  or  to  show  the  Leased  Premises  to
           prospective  lenders  or  purchasers,  and,  during  the  last
           twelve (12) months  of the term, to  show them to  prospective
           tenants at  reasonable  hours and,  if  they are  vacated,  to
           prepare them for re-occupancy.

                (e)  To retain at  all times, and  to use in  appropriate
           instances,  keys to  all  doors  within and  into  the  teased
           Premises. No  locks  shall be  changed  or added  without  the
           prior written consent of Landlord.
<PAGE>
                (f)  To decorate  and  to   make  repairs,   alterations,
           additions, changes,  or  improvements, whether  structural  or
           otherwise, in  and about the  Building, or  any part  thereof,
           and for such purposes to  enter upon the teased Premises  and,
           during the  continuance of any  of said  work, to  temporarily
           close doors,  entryways, public  space, and  corridors in  the
           Building,  to  interrupt   or  temporarily  suspend   Building
           services and  facilities  and to  change the  arrangement  and
           location of  entrances  or passageways,  doors  and  doorways,
           corridors, elevators, stairs,  toilets, or other public  parts
           of the  Building, an without  abatement of  rent or  affecting
           any of Tenant's obligations hereunder,  so long as the  teased
           Premises are reasonably accessible.

                (g)  To grant to  anyone the exclusive  right to  conduct
           any business  or render  any service  in or  to the  Building,
           provided such  exclusive tight  shall not  operate to  exclude
           tenant from the use expressly permitted herein,

                (h)  To take  all such  reasonable measures  as  landlord
           may  deem  advisable  for  the  security  and  safety  of  the
           Building and its occupants,

                (j)  Landlord shall have  the right to transfer,  assign,
           or convey. in whole or in part, the Building and the land  and
           any and all of its rights  wider this tease, and in the  event
           Landlord transfers, assigns, or conveys its rights under  this
           tease, Landlord  shall thereby  be released  from any  further
           obligations hereunder  and  Tenant agrees  to look  solely  to
           such successor in interest of the Landlord for performance  of
           such obligations.

           18.  FIRE OR OTHER  CASUALTY. If  the Leased  Premises or  any
     part  thereof shall be  damaged by  fire or  other casualty,  Tenant
     shall give  prompt written notice thereof  to Landlord. In case  the
     Building  shall  be  so damaged  by  fire  or  other  casualty  that
     substantial alteration or  reconstruction of the Building shall,  in
     Landlords  sole opinion,  be required  (whether  or not  the  Leased
     Premises shall have been damaged by such fire or other casualty)  or
     in  the event  any  mortgagee under  a  mortgage or  deed  of  trust
     covering  the Building should  require that  the insurance  proceeds
     payable  as a  result of  said fire  or other  casualty be  used  to
     retire the  mortgage debt, Landlord  may, at  its option,  terminate
     this  Lease and  the term  and estate  hereby granted  by  notifying
     Tenant in writing of  such termination within sixty (60) days  after
     the date of such damage, in which event the rent hereunder shall  be
     abated as  of the date  of such damage.  If Landlord  does not  thus
     elect to  terminate this Lease,  Landlord shall within  seventy-five
     (75)  days after  the date  of such  damage commence  to repair  and
     restore the Building and shall proceed with reasonable diligence  to
     restore the Building (except that Landlord shall not be  responsible
     for delays outside its control) to substantially the same  condition
     in which it was immediately prior to the happening of the  casualty,
     except that  Landlord shall not  be required to  rebuild, repair  or
     replace  any  part  of  Tenant's  furniture  or  furnishings  or  of
     fixtures and equipment  removable by Tenant under the provisions  of
     this tease.  Landlord shall not be  liable for any inconvenience  or
     annoyance to  tenant or injury to  the business of Tenant  resulting
<PAGE>
     in  any way  from such  damage or  the repair  thereof; except  that
     during  the time  and to  the extent  that the  Leased Premises  are
     unfit  for occupancy,  the Landlord  shall,  at its  option,  either
     furnish the Tenant with comparable space at prevailing market  rates
     or a  fair diminution of rent,  the choice of which  will be at  the
     landlord's  sole  discretion,  if the  damages  are  caused  by  the
     negligence of Tenant, its agents, servants, employees,  contractors,
     patrons, guests, licensees,  or invitees there will be no  abatement
     of rent and Tenant will  be liable for any damages in excess of  the
     amount  paid  by  insurance  proceeds  received  by  Landlord.   Any
     insurance which may be carried by Landlord or Tenant will be  liable
     for  any damages  in  excess of  the  amount paid  by  or  insurance
     proceeds received  by Landlord. Any insurance  which may be  carried
     by Landlord Tenant against loss or damage to the Building or to  the
     Leased Premises shall be for the sole benefit of the party  carrying
     such insurance and under its sole control.

           19.  CONDEMNATION. If the whole or substantially the whole  of
      the Building  and land or  of the Leased  Premises should be  taken
      for any  public or  quasi-public use  under any  governmental  law,
      ordinance or regulation or by right of eminent domain or should  be
      sold to  the condemning  authority in  lieu of  condemnation,  then
      this Lease shall terminate as of the date when physical  possession
      of the Building  and land or  the Leased Premises  is taken by  the
      condemning authority. If less  than the whole or substantially  the
      whole of the Building and land or the Leased Premises are  affected
      thereby,  Landlord  may terminate  this  Lease  by  giving  written
      notice thereof to Tenant within sixty (60) days after the right  of
      election accrues, in which  event this Lease shall terminate as  of
      the date when physical  possession of such portion of the  Building
      and land or Leased  Premises is taken by the condemning  authority.
      If  upon any  such  taking  or  sale of  less  than  the  whole  or
      substantially the  whole of  the Building  and land  or the  teased
      Premises this Lease shall not be thus terminated, the rent  payable
      hereunder shall be diminished  by an amount representing that  part
      of said rent as shall property  be allocable to the portion of  the
      Leased Premises which was so  taken or sold and Landlord shall,  at
      Landlord's sole expense, restore  and reconstruct the Building  and
      land  and  the  Leased  Premises  to  substantially  their   former
      condition to the extent that the same, in Landlord's judgment,  may
      be feasible, but such work shall  not exceed the scope of the  work
      done  by  Landlord in  originally  constructing  the  Building  and
      installing tenant  improvements in  the teased  Premises nor  shall
      Landlord in any event be required to spend for such work an  amount
      in excess of  the amount received by  Landlord as compensation  for
      damages (over  and above  amounts  going to  the mortgagee  of  the
      property taken)  for  the part  of the  Building  and land  or  the
      teased Premises  so taken. Landlord  shall be  entitled to  receive
      all of the compensation  awarded upon a taking  of any part or  all
      of the  Building and  land  or the  Leased Premises  including  any
      award for  the value  of unexpired term  of this  Lease and  Tenant
      shall not  be entitled  to and expressly  waives all  claim to  any
      such compensation  provided, however, Tenant  shall be entitled  to
      receive an award for damages to Tenant's leasehold improvements.
<PAGE>
           20.  TAXES. Tenant  shall be liable  for all  taxes levied  or
      assessed against personal  property, furniture  or fixtures  placed
      by Tenant in the teased Premises,  and if any such taxes for  which
      Tenant  is liable  are  in  any  way  levied  or  assessed  against
      Landlord, tenant shalt  pay to Landlord  upon demand  that part  of
      such  taxes  for  which  Tenant  is  primarily  liable   hereunder.
      Notwithstanding  any  other  provision  contained  in  this  tease.
      Tenant shall pay  any and all licenses,  charges and other fees  of
      every kind and nature  as and when they  become due and before  the
      saint become delinquent  arising out of or  in connection with  use
      and occupancy of  the Leased Premises,  including, but not  limited
      to,  license  fees,  business  license  tax,  the  amount  of   any
      privilege, sales, excise or other  tax (other than income)  imposed
      upon rentals herein provided to be paid by Tenant or upon  Landlord
      in an amount measured by such rentals received by Landlord.

         21.  SURRENDER UPON  TERMINATION.  At the  termination  of  this
    Lease, whether caused by lapse of time or otherwise. Tenant shall  at
    once surrender  possession of  the Leased  Premises and  deliver  the
    Leased Premises to  Landlord in as  good repair and  condition as  at
    the commencement of Tenant's occupancy, reasonable wear and tear  and
    damages or destruction  by fire or  other insured casualty  excepted,
    and shall deliver to Landlord  all keys to the Leased Premises,  and,
    if such  possession  is  not immediately  surrendered,  Landlord  may
    forthwith enter upon and take  possession of the Leased Premises  and
    expel or  remove Tenant and  any other  person who  may be  occupying
    said premises, or any part  thereof, by force, if necessary,  without
    having any  civil or  criminal liability  therefor. All  alterations,
    additions,  or  improvements  (whether  temporary  or  permanent   in
    character) made in  or upon the  Leased Premises  shall, if  Landlord
    elects, be  Landlord's  property on  termination  of this  Lease  and
    shall remain on the Leased  Premises without compensation to  Tenant.
    All furniture,  movable trade  fixtures, and  equipment installed  by
    Tenant may be  removed by Tenant  at the termination  of this  Lease,
    All  removals permitted  herein  shall  be  accomplished  in  a  good
    workmanlike manner so  as not to  damage the Leased  Premises or  the
    Building. Tenant, or Landlord at  Tenant's expense, shall repair  any
    damage to the  Leased Premises, the  Building or  any improvement  on
    the  lands  herein  described  caused   by  any  such  removal.   All
    furniture, movable trade fixtures  and equipment installed by  tenant
    not removed at the  end of the tease  Term hereof shall thereupon  be
    conclusively presumed to have been  abandoned by Tenant and  Landlord
    may, at its  option, take over  the possession of  such property  and
    either (i) declare  same to be  the property of  Landlord by  written
    notice thereof to Tenant or (ii) at the sole risk, cost, and  expense
    of Tenant remove  the same  or any part  thereof in  any manner  that
    Landlord shall choose and store the  same or any part thereof in  any
    manner  that  Landlord  shall  choose  and  store  the  same  without
    incurring liability to Tenant or any other person.
<PAGE>
         22.  DEFAULT. In the  event of default in  any of the  covenants
    or conditions  herein, Landlord may assert  any remedies provided  to
    an aggrieved landlord by law, without limiting the generality of  the
    foregoing, Landlord, at its option, shall have any one or all of  the
    following  remedies  which are  cumulative  and  not  exclusive:  (a)
    Landlord  may declare the  Lease forfeited, but  such declaration  or
    forfeiture  shall not  terminate  Tenant's duty  to pay  rentals  and
    additional  rent hereunder, nor  waive any other  rights of  Landlord
    unless Landlord specifically  so states in writing: (b) Landlord  may
    re-enter  the Leased Premises  and remove all  persons and  property,
    including  that of  Tenant or  any third  persons therefrom,  without
    being guilty  of any manner of trespass  or conversion, but any  such
    re-entry  shall  not  terminate Tenant's  duty  to  pay  rentals  and
    additional  rent hereunder  nor waive  any other  rights of  Landlord
    unless Landlord specifically  so states in writing: (c) Landlord  may
    resume possession of the  Leased Premises and relet the same for  the
    account of Tenant, who  shall make good any deficiency: (d)  Landlord
    may  recover all arrearages  of rent and  additional rent  hereunder:
    (e)  Landlord  may  declare  the  entire  amount  of  the  rent   and
    additional rent  hereunder, which would have  become due and  payable
    during the term of this Lease, to be due and payable immediately,  in
    which event,  Tenant agrees to  pay the same  at once, together  with
    all rents  and additional rents theretofore  due, to Landlord at  the
    address specified  herein or hereunder; provided, however, that  such
    payments shall not  constitute a penalty or forfeiture or  liquidated
    damages,  but shall  merely  constitute a  penalty or  forfeiture  or
    liquidated damages,  but shall merely  constitute payment in  advance
    of the  rent for the remainder of the  term: (f) Tenant, in  addition
    to  rentals and additional  rent hereunder, shall  be liable for  all
    damages  and  expenses  which Landlord  has  suffered  by  reason  of
    Tenant's  default:  including, but  not  limited to,  damage  to  the
    Leased  Premises (which  shall be  measured at  Landlord's option  by
    landlord's  cost to  repair the  same  or by  the difference  in  the
    market value  of the Leased Premises  before and after such  damage),
    cost of reletting. (e.g., advertising the Leased Premises for  lease,
    preparation of a new  lease agreement, etc.), attorney fees, cost  of
    court,  cost  of repossession  and  other  special  or  consequential
    damages:  (g)  Landlord shall  have,  in addition  to  any  statutory
    liens, the right to  seize and possess, as security for all sins  due
    hereunder from  Tenant, all the goods, wares, merchandise,  chattels,
    implements, fixtures, tools and other personal property which are  or
    may be  put upon the teased Premises and  Landlord shall have a  lien
    upon  an such  property which  may  be possessory  but shall  not  be
    required  to be. Tenant  hereby waives all  exemptions in  connection
    with  such  property,  which could  otherwise  be  available  to  it.
    Landlord  shall give  Tenant  ten (10)  days  written notice  of  any
    default  herein. for the  purpose of the  foregoing. Tenant shall  be
    deemed to  be in default under this Lease  if Tenant: (1) has  failed
    to pay any installment  of rent or other amount when due. Whether  or
    not such  payment shall have been demanded:  (2) fails to perform  or
    comply with  any of the other  conditions or agreements expressed  or
    implied  herein and fails  to remedy such  lack of compliance  within
    thirty (30) days after written notice from Landlord of such  default;
    (3)  abandons, vacates or  does not  occupy the  teased Premises  for
    fourteen  (1/4) consecutive  days; and  (4) liquidates  or ceases  to
    exist, admits insolvency, seeks  relief under any law for the  relief
    of debtors,  makes an assignment for the  benefit of creditors or  is
    the subject of a  voluntary or involuntary petition in bankruptcy  or
<PAGE>
    receivership, or  in the event of any  like occurrence which, in  the
    sole  and  absolute  judgment  of  Landlord,  evidences  the  serious
    financial insecurity of Tenant or if the estate hereby created  shall
    be levied upon or  taken by execution or process of law, then and  in
    any such  event, regardless of any waiver  or consent to any  earlier
    event  or  events  of  default.  In  the  event  that  any  court  or
    governmental authority shall limit any amount, which Landlord may  be
    entitled to recover pursuant  to the terms hereof, Landlord shall  be
    entitled to recover  the maximum amount permitted under law.  Nothing
    herein  contained shall  be deemed  to limit  or restrict  Landlord's
    recovery from Tenant of the maximum amount permitted under law or  of
    any  other sums  or damages  which  Landlord way  be entitled  to  so
    recover  in  addition  to  the  damages  set  forth  herein,  Nothing
    contained  herein shall be  deemed to require  Landlord to relet  the
    Leased  Premises or  to take  any  other action  with retard  to  the
    Leased Premises and Landlord  shall not be liable for any failure  to
    relet,  collect rent, or  take any other  action with  regard to  the
    teased  Premises  after termination  pursuant  to the  terms  hereof.
    Tenant  hereby waives any  right of redemption,  which Tenant may  at
    any time  have by reason of  Tenant's default or eviction  hereunder.
    The  parties hereto expressly  agree that this  Lease and the  estate
    created  hereby shall not  continue or inure  to the  benefit of  any
    assignee, receiver or trustee  in bankruptcy except at the option  of
    Landlord.  In addition  to  other remedies  provided in  this  Lease,
    Landlord  shall be entitled,  to the extent  permitted by  applicable
    law, to injunctive relief  in case of the violation, or attempted  or
    threatened   violation,  of   any  of   the  covenants,   agreements,
    conditions  or provisions of  this Lease, or  to a decree  compelling
    performance of  any of. The  other covenants, agreements,  conditions
    or  provisions of  this Lease,  or  to any  other remedy  allowed  to
    Landlord  at law or  in equity. Tenant  hereby expressly agrees  that
    the damages provided for herein constitute just compensation for  the
    loss or damages which may be actually sustained by Landlord and  that
    such damages are just and reasonable.

          23.  NO IMPLIED  WAIVER The failure  of Landlord  to insist  at
     any time upon  the strict performance of  any covenant or  agreement
     or to  exercise any  option, right,  power, or  remedy contained  in
     this Lease shall  not be construed as  a waiver or a  relinquishment
     thereof for the future. The  waiver of or redress for any  violation
     of any  term, covenant, agreement,  or condition  contained in  this
     Lease or  contained in  the Rules  and Regulations  attached to  and
     forming a  part of this  Lease shall not  prevent a subsequent  act,
     which would have originally constituted a violation from having  all
     the force  and effect of  an original violation.  No express  waiver
     shall affect  any condition  other than  the one  specified in  such
     waiver  and  that  one  only   for  the  time  and  in  the   manner
     specifically  stated.  A  receipt  by  landlord  of  any  rent  with
     knowledge of the  breach of any covenant  or agreement contained  in
     this Lease  shall not  be deemed  a waiver  of such  breach, and  no
     waiver by Landlord  of any provision of  this Lease shall be  deemed
     to  have  been made  unless  expressed  in  writing  and  signed  by
     Landlord,

           24.  ATTORNEYS' FEES AND LEGAL EXPENSES. Each party shall  pay
      to the other party  upon demand all  reasonable attorneys fees  and
      all expenses and court  costs of such  party incurred in  enforcing
      any of the obligations of the other party under this Lease.
<PAGE>
           25.  WORK  AGREEMENT.  The   improvements  and   installations
      specified in Exhibit "E"  hereof shall be  made in accordance  with
      the plans  and specifications  provided for  in Exhibit  "E" on  or
      prior to the Rental Commencement Date.

           26. LANDLORD'S  LEIN In addition  to the statutory  landlord's
      lien, Landlord shall have,  at all times, and Tenant hereby  grants
      to Landlord,  a valid security  interest to secure  payment of  all
      rent and  other suns of money  becoming due hereunder from  tenant,
      and to  secure payment of  any damages or  loss which Landlord  may
      suffer  by  reason  of  the  breach  by  Tenant  or  any  covenant,
      agreement or  condition contained  herein, upon  all goods,  wares,
      equipment,  fixtures, furniture,  improvements and  other  personal
      property of Tenant presently or which may hereafter be situated  on
      the Leased Premises, and all proceeds therefrom, and such  property
      shall  not be  removed therefrom  without the  consent of  Landlord
      until all arrearages in rent as  well as any and all other sums  of
      money then  due to Landlord  hereunder shall first  have been  paid
      and discharged  and all  the covenants.  agreements and  conditions
      hereof  have been  fully complied  with  and performed  by  Tenant.
      Landlord agrees that  any such statutory lien or security  interest
      shall be  subject and subordinate  to any  purchase money  security
      interest  to  the extent  such  purchase  money  security  interest
      attaches  to   Tenant's  computer  systems   or  other   laboratory
      equipment  having a  unit  cost of  $20,000.00  or more.  Upon  the
      occurrence of  any event  of default  by Tenant,  Landlord may,  in
      addition  to any  other remedies  provided herein,  enter upon  the
      Lease Premises  and take possession  of any and  all goods,  wares,
      equipment,  fixtures, furniture,  improvements and  other  personal
      property  of  Tenant  situated  on  the  Lease  Premises,   without
      liability for trespass or  conversion, and sell the same at  public
      or private sale, with or without having such property at the  sale,
      after giving tenant reasonable notice of the time and place of  any
      public sale or  of the tine after which any  private sale is to  be
      made, at  which sale Landlord  or its assigns  may purchase  unless
      other-wise prohibited  by law.  Unless otherwise  provided by  law,
      and without intending to exclude any other manner of giving  Tenant
      reasonable notice,  the requirement of  reasonable notice shall  be
      met if such notice is given in the manner prescribed in this  tease
      at least five (5) days before  the time of sale. The proceeds  from
      any such disposition, less any and all expenses connected with  the
      taking  of  possession,   holding  and  selling  of  the   property
      (including reasonable  attorneys' fees and  other expenses),  shall
      be applied  as a  credit against  the indebtedness  secured by  the
      security interest granted  in this Paragraph 25. Any surplus  shall
      be  paid to  Tenant or  as otherwise  required by  law, and  Tenant
      agrees to execute and deliver to Landlord a financing statement  in
      form sufficient  to perfect the  security interest  of Landlord  in
      the  aforementioned  property   and  proceeds  thereof  under   the
      provisions of the Uniform Commercial Code in force in the State  of
      Texas.  The Statutory  lien  for rent  is  not hereby  waived,  the
      security   interest   herein  granted   being   in   addition   and
      supplementary thereto.
<PAGE>
           27.  SUBORDINATION.

           (a)  Except as  other-wise provided  to the  contrary  herein,
      Tenant agrees that  this Lease shall  at all times  be subject  and
      subordinate to the  lien of any  mortgage (including any  amendment
      or  modification thereof,  whether  made  prior  or  subsequent  to
      request for  subordination)  which  may be  placed  on  the  teased
      Premises by  Landlord, if  requested in  writing by  the bolder  or
      prospective holder  thereof; provided,  that  Tenant shall  at  all
      times be entitled  to possession tinder  this Lease so  long as  it
      complies with the terms herein  set out, subject to the  conditions
      hereinafter  expressed. Tenant  agrees,  upon  demand  and  without
      cost, to execute any  instrument as nay  be required to  effectuate
      such subordination which instruments shall include, among and  with
      any other  provisions required by  the Mortgagee,  an agreement  on
      the part  of Tenant  to  attorn to  any  and all  successors  their
      interest to the Leased Premises  resulting from any foreclosure  of
      any such  mortgage or  conveyance in  lieu of  the foreclosure.  At
      the-date  hereof,  there  are  no  outstanding  mortgages  on   the
      Building.

           (b)  Anything to the  contrary herein notwithstanding,  Tenant
     covenants and  agrees that if  the present or  future holder of  any
     mortgage  (including  any  amendment  and/or  modification  thereof,
     whether made  prior or subsequent  to the subordination  hereinabove
     provided  for)  affecting  the  Leased  Premises  subordinates  said
     mortgage  to this  Lease, whether  the same  be  part of  a  general
     subordination  by such  Mortgagee  or specifically  refers  to  this
     Lease,  then this  Lease  shall  for all  intents  and  purposes  be
     considered to be paramount  and superior to said mortgage and  shall
     survive  and continue  to  remain in  full  force and  effect,  even
     though said mortgage  be foreclosed; and,  Tenant shall continue  to
     comply with all  of its obligations hereunder,  whether or not  said
     mortgage be foreclosed; and,  in the event of any such  foreclosure,
     Tenant agrees to thereafter attorn to the Mortgagee, its  successors
     and assigns,  and to any  purchaser at  foreclosure, its  successors
     and assigns.

           (c) Tenant agrees  that it will  not (i) prepay  any rents  or
      other charges  more than thirty  (30) days  in advance  of the  due
      date required by this Lease  without prior written consent of  said
      Mortgagee: (ii) terminate this  lease or exercise  a right of  set-
      off, if any  there be, except  for the default  of Landlord  (after
      giving written notice to  the Mortgagee and  a reasonable time  for
      the Mortgagee to correct  such default) or  (iii) amend this  Lease
      without the prior consent of the Mortgagee.

          (d)  Tenant will, upon receipt of demand therefor, at any  time
     or times, execute, acknowledge, and deliver to Landlord any and  all
     instruments and  certificates that  may be  necessary or  proper  to
     more effectively  effectuate the provisions  hereof, This lease  and
     all rights of Tenant hereunder are further subject and  subordinate,
     to the extent that  the same relate to  the Leased Premises, to  all
     applicable ordinances  of the  City of  Irving, Texas,  relating  to
     easements, franchises,  and other interests  or rights upon,  across
     or appurtenant to the building or  any of the Land, and all  utility
     easements and agreements.
<PAGE>
           28.  QUIET ENJOYMENT. Provided  Tenant pays  the rent  payable
     hereunder as and when due and payable and keeps and fulfills all  of
     the terms, covenants, agreements  and conditions to be performed  by
     Tenant hereunder, Tenant  shall at all times  during the Lease  Term
     peaceably  and  quietly  enjoy  the  Leased  Premises  without   any
     disturbances from  Landlord or from  any other  person claiming  by,
     through  or  under  Landlord,  subject  to  the  terms,  provisions,
     covenants, agreements and conditions of this tease and to the  deeds
     of  trust, mortgages.  ground  leases, ordinances,  leases,  utility
     easements  and  agreements  to  which  this  Lease  is  subject  and
     subordinate, as hereinabove set forth.

           29.  NOTICE TO LANDLORD In the event of any act or omission by
     Landlord which would give Tenant the right to damages from  Landlord
     or the right to terminate this Lease by reason of a constructive  or
     actual  eviction  from  all  or  part  of  the  Leased  Premises  or
     otherwise, Tenant  shall not sue  (or such damages  or exercise  any
     such  right to  terminate  until (i)  it  shall have  given  written
     notice  of  such  act   or  omission  to  Landlord  and   Landlord's
     mortgagee,  if  any, and  (ii)  a  reasonable  period  of  time  for
     remedying such  act or  omission shall  have elapsed  following  the
     giving  of such  notice, during  which  time Landlord,  its  agents,
     employees or  its mortgagee  shall  be entitled  to enter  upon  the
     Leased Premises and do  therein whatever may be necessary to  remedy
     such act  of omission. hiring  the period after  the giving of  such
     notice and  during the remedying  of such act  or omission the  rent
     payable by tenant  for such period as  provided in this Lease  shall
     be abated and apportioned  only to the extent  that any part of  the
     Leased Premises shall be untenantable.

          30.  HOLDING  OVER  BY TENANT.  Should  Tenant or  any  of  its
      successors in interest continue to  hold the Leased Premises  after
      the termination of this Lease,  whether such termination occurs  by
      lapse of time or otherwise, such holding over shall constitute  and
      be construed as a  tenancy from month to  month only, at a  monthly
      rental equal to  150% of the  monthly rent provided  herein at  the
      time of such termination, hiring such time as Tenant shall continue
      to hold the  Leased Premises after  the termination hereof,  Tenant
      shall continue to  hold the Leased  Premises after the  termination
      hereof. Tenant shall be regarded as  a Tenant from month to  month;
      subject, however, to  all of  the terms,  provisions covenants  and
      agreements on the part of Tenant hereunder. No payments of money by
      Tenant to  Landlord  after  the termination  of  this  Lease  shall
      reinstate, continue,  or  extend the  term  of this  Lease  and  no
      extension of  this Lease  after the  termination thereof  shall  be
      valid unless and  until the same  shall be reduced  to writing  and
      signed by both Landlord and Tenant.
<PAGE>
          31.     RULES AND  REGULATIONS   Tenant  and  Tenant's  agents,
     employees,  and invitees will  comply with all  requirements of  the
     Rules  and Regulations (as changed from time to time as  hereinafter
     provided)  which are attached hereto as Exhibit "B" and made a  part
     hereof  as though fully set out herein. Landlord shall at all  times
     have  the  right  to  change  such  Rules  and  Regulations  or   to
     promulgate other Rules and Regulations in such reasonable manner  as
     may  be deemed advisable for the safety, care or cleanliness of  the
     Building and related facilities or premises and for preservation  of
     good  order therein; provided, however, that such changes shall  not
     become  effective and  a part  of this  Lease until  a copy  thereof
     shall  have  been  delivered to  Tenant.  Tenant  shall  further  be
     responsible  for the compliance with  such Rules and Regulations  by
     the  employees, servants, agents, visitors, and invitees of  Tenant.
     Landlord  shall not  be responsible  to Tenant  for failure  of  any
     person  to comply with such Rules and Regulations No such  amendment
     shall  have the effect of  changing any of the  basic terms of  this
     Lease.

          32.  ESTOPPEL  CERTIFICATE Tenant will,  at any  time and  from
      time to time, upon not less than twenty (20) days' prior request by
      Landlord, execute, acknowledge and deliver to landlord a  statement
      in writing executed  by Tenant certifying  that this  Lease is  the
      entire agreement between the parties and is unmodified and in  full
      effect (or, if there have been modifications, that this Lease is in
      full effect as modified, and setting forth such modifications)  and
      the dates to  which the  rent has been  paid, that  the Tenant  has
      unconditionally accepted the  Leased Premises,  and either  stating
      that to the knowledge of the signer of such certificate no  default
      exists hereunder  or  specifying each  such  default of  which  the
      signer  may  have  knowledge;  it  being  intended  that  any  such
      statement by Tenant may be relied upon by any prospective purchaser
      or mortgagee of the Building.

          33.  PERSONAL  LIABILITY. The liability  of Landlord to  Tenant
      for any default by landlord under the terms of this Lease shall  be
      limited to the interest  of Landlord in the  Building and land  and
      landlord shall not  be personally liable  for any deficiency.  This
      clause shall not  be deemed  to limit  or deny  any remedies  which
      Tenant may have in the event of default by Landlord hereunder which
      do not involve the personal liability of Landlord,

          34.  BROKERAGE. Each party hereto  warrants that it has had  no
     dealings   with  any  broker  or   agent  in  connection  with   the
     negotiation  or  execution  of  this  Lease  other  than  Cushman  &
     Wakefield  of   Texas,  Inc.  and,  JPI  Realty,  Inc.   hereinafter
     collectively referred to as the "Brokers". Each party hereto  agrees
     to   indemnify  the  other  party   against  all  costs,   expenses,
     attorneys'  fees  or  other  liability  for  commissions  or   other
     compensation or  charges claimed by any broker or agent, other  than
     Brokers, claiming  the same by through, or under it with respect  to
     the  original term thereof  or any renewal  or extension thereof  or
     with  respect  to  any  expansion  of  the  Leased  Premises.    The
     brokerage commission  payable to the Brokers, if any, shall be  paid
     by  Landlord pursuant to the terms  of a separate agreement  between
     landlord and the Brokers.
<PAGE>
          35.   NOTICES. Each  provision of  this  agreement, or  of  any
      applicable governmental  lawn,  ordinances, regulations  and  other
      requirements with reference to the sending, mailing or delivery  of
      any notice,  or with  reference to  the making  of any  payment  by
      tenant to Landlord, shall  be deemed to be  complied with when  and
      if the following steps are taken:

                (a) All rent and  other payments required  to be made  by
          tenant  to Landlord hereunder shall  be payable to Landlord  in
          Dallas  County,  Texas. at  the address  set  forth on  Page  1
          hereof  or at such other address  as Landlord may specify  from
          time  to  time  by  written  notice  delivered  in   accordance
          herewith.

                (b)  Any notice  or  document required  to  be  delivered
          hereunder shall be deemed to be delivered if actually  received
          and  whether  or not  received  when deposited  in  the  United
          States  wail,  postage  prepaid certified  or  registered  mail
          (return receipt  requested) addressed to the parties hereto  at
          their  respective addresses set  forth on Page  1 hereof or  at
          such other  address as either of said parties have  theretofore
          specified by written notice delivered in accordance herewith.

          36.   SEVERABILITY.  Each and  every  covenant  and   agreement
      contained in  this  Lease is,  and  shall  be construed  to  be,  a
      separate and  independent covenant and  agreement. If  any term  or
      provision of this Lease  or the application  thereof to any  person
      or circumstances shall to any extent be invalid and  unenforceable,
      the remainder of  this Lease, or  the application of  such term  or
      provision to persons or circumstances other than those as to  which
      it is invalid Or unenforceable, shall not be affected thereby.

          37.   NO MERGER. There shall be no merger of  this Lease or  of
      the leasehold  estate hereby  created with  the fee  estate in  the
      Leased Premises or any part thereof by reason of the fact that  the
      same person  may  acquire or  hold,  directly or  indirectly,  this
      Lease or the  leasehold estate hereby  created or  any interest  in
      this Lease or in  such leasehold estate as  welt as the fee  estate
      in the Leased Premises or any interest in such fee estate.

          38.   FORCED  MAJEURE. Whenever  a period  of  time  is  herein
      prescribed for  action to  be  taken by  Landlord or  Tenant,  such
      party shall not be  liable or responsible for,  and there shall  be
      excluded from  the computation  for any  such period  of time,  any
      delays  due  to  strike,  acts  of  God,  shortages  of  labor   or
      materials, war,  governmental laws,  regulations, restrictions,  or
      any  other cause  of  any  kind  whatsoever  which  is  beyond  the
      reasonable control  of  such  party; provided,  however,  that  the
      foregoing shall  not in  any event  excuse Tenant  from the  prompt
      payment of rent or any other monetary obligations hereunder.

          39.   GENDER. Words of any Lender  used in this Lease shall  be
      held and construed  to include any  other gender and  words in  the
      singular number shall  be held to  include the  plural, unless  the
      context otherwise requires.

          40.   JOINT SEVERAL ABILITY. If there be more than one  Tenant,
      the obligations hereunder  imposed upon Tenant  shall be joint  and
      several.
<PAGE>
          41.   NO REPRESENTATIONS.  Landlord or  Landlord's agents  have
      made no  representations or  promises with  respect to  the  Leased
      Premises,  the  Building  licenses   are  acquired  by  Tenant   by
      implication or  otherwise  except as  expressly  set forth  in  the
      provisions of this Lease.

          42.   ENTIRE  AGREEMENT  This  Lease  sets  forth  the   entire
      agreement between the parties and  no amendment or modification  of
      this Lease shall be binding or valid unless expressed in a  writing
      executed by both parties hereto.

          43.   PARAGRAPH HEADINGS Paragraph  headings contained in  this
      Lease are  for convenience  only and  shall in  no way  enlarge  or
      limit the scope or  meaning of the  various and several  paragraphs
      hereof.

          44.   BINDING EFFECT. All of the covenants, agreements,  terms,
      and conditions to be observed and  performed by the parties  hereto
      shall be applicable  to and  binding upon  their respective  heirs,
      personal representatives, successors, and to the extent  assignment
      is permitted hereunder, their respective assigns,

          45.   RIDERS AND EXHIBITS.  the following  numbered Riders  and
      lettered Exhibits are  attached hereto and  incorporated herein  by
      reference for all purposes.

                Riders No. 1 and 2
                Exhibits No. A, B. C, and D

          46.   EXECUTION OF  LEASE BY  LANDLORD. Except  for the  person
  executing this lease as an officer of Landlord, employees or agents  of
  Landlord, or of Landlord's broker, if any, have no authority to make or
  agree to  make  a  lease  or any  other  agreement  or  undertaking  in
  connection herewith. The  submission of this  document for  examination
  and negotiation does not constitute an offer to lease, or a reservation
  of, or  option  for, the  Leased  Premises and  this  document  becomes
  effective and binding only  upon the execution  and delivery hereof  by
  Landlord and Tenant. All negotiations, considerations,  representations
  and understandings between Landlord and Tenant are incorporated  herein
  and may be  modified or altered  only by agreement  in writing  between
  Landlord and Tenant, and no act or omission or any employee or agent of
  Landlord or of Landlord's broker, if any, shall alter, change or modify
  any of the provisions herof.

                               LANDLORD:
                               WESTERN ATLAS INTERNATIONAL, INC.

                               BY: /S/
                                   ------------------------------
                                   Printed Name:
                                   Title:

                               TENANT:
                               CARRINGTON LABORATORIES, INC.

                               BY: /S/
                                   ------------------------------
                                   Printed Name:
                                   Title:
<PAGE>

                                EXHIBIT "B"


                          To Lease By and Between

               WESTERN ATLAS INTERNATIONAL, INC, as Landlord

                                    and

                 CARRINGTON LABORATORIES, INC., as Tenant


                        Building Rules and Regulations

          1.  No birds, animals, reptiles, or any other creatures, shall
      be brought into or about the Building.

          2.  Nothing shall be swept or thrown into the corridors, halls,
      elevator shafts or stairways.

          3.  Tenant shall not make or permit any improper noises in the
      Building, create a nuisance, or do or permit anything which, in
      Landlord's reasonable judgment, interferes in any way with other
      tenants or persons having business with them.

          4.  No equipment of any kind shall be operated on the Leased
      Premises that could in any way annoy any other tenant in the
      Building without the prior written consent of Landlord.

          5.  Tenant shall cooperate  with Building employees in  keeping
     the Leased Premises neat and clean

          6.  Corridor doors, when not in use, shall be kept closed.

          7.  No bicycles  or similar  vehicles will  be allowed  in  the
      Building.

          8.  Tenant   will   refer    all   contractors,    contractor's
      representatives,  and   installation  technicians   rendering   any
      service on or to  the leased premises for  Tenant to Landlord,  for
      Landlord's  approval  and  supervision   for  performance  of   any
      contractual  service.  This  provision  shall  apply  to  all  work
      performed in the  Building, including  installation of  telephones,
      telegraph  equipment,  electrical  devices,  and  attachments   and
      installations of  any  nature affecting  floors,  walls,  woodwork,
      trim, windows, ceiling,  equipment, or any  other physical  portion
      of the Building.

          9.  No nails, hooks, or screws shall be driven into or inserted
      in  any  part  of  the  Building  except  by  Building  maintenance
      personnel.
<PAGE>
          10. Sidewalks,  doorways,  vestibules,  halls,  stairways,  and
      similar areas shall not  be obstructed by  Tenant or its  officers,
      agents, servants,  and employees,  or used  for any  purpose  other
      than ingress and  egress to and  from the Leased  Premises, or  for
      going from  one  part  of  the Building  to  another  part  of  the
      Building. No furniture shall  be placed in  front of the  Building,
      or in any lobby or corridor without written consent of Landlord.

          11. Tenant, its  employees,  or  agents,  or  anyone  else  who
      desires to enter the Building  after normal working hours, will  be
      required to sign in  upon entry and sign  out upon leaving,  giving
      the location  during  their stay  and  their time  of  arrival  and
      departure. Normal  working hours means  7:30 a.m.  until 6:00  p.m.
      daily  and  8:0O  a.m.  until  1:00  p.m.  on  Saturdays,  holidays
      excepted, but the  Building will be  accessible by sign-in  twenty-
      four (24) hours per day.

          12. All deliveries must  he made via  the service entrance  and
      service elevator, when  provided during normal working hours or  at
      such  times  as Landlord  lay  determine. Prior  approval  must  be
      obtained  from  the  Landlord  for  all  deliveries  that  must  be
      received after normal working hours.

          13. Landlord  or its agents  or employees shall have the  right
       to enter  the Leased Premises to examine the same or to make  such
       repairs,   alterations,  or  additions  as  Landlord  shall   deem
       necessary  for the  safety, preservation,  or improvement  of  the
       Building.

           14. Landlord has  the right to  evacuate the  Building in  the
       event of an emergency or catastrophe.

           15. Tenant shall  not do anything,  or permit  anything to  be
       done,  in  or  about  the building,  or  bring  to  keep  anything
       therein, that will in any way increase the possibility of fire  or
       other  casualty, or do anything in  conflict with the valid  laws,
       rules, or regulations of any governmental authority.

           16. Tenant shall  notify the  Building Manager  when safes  or
       other  equipment are  to be  taken into  or out  of the  Building.
       Moving  of such items shall be done  under the supervision of  the
       Building Manager, after receiving written permission from him.

           17. Landlord shall have the power to prescribe the weight  and
       position of  safes or other heavy equipment, which may  overstress
       any portion  of the floor. All damage done to the Building by  the
       improper  placing of heavy items  which overstress the floor  will
       be repaired at the sole expense of the Tenant.

           18. No food shall be distributed from tenant's office  without
       the prior written approval of the Building Manager.

           19. No  additional  locks  shall  be  placed  upon  any  doors
       without the prior written consent of Landlord, All necessary  keys
       shall be furnished by Landlord, and the same shall be  surrendered
       upon  termination  of  this  Lease  and  Tenant  shall  then  give
       Landlord  or his agent  an explanation of  the combination of  all
       locks on the doors and vaults.
<PAGE>
           20. Tenant shall comply with parking rules and regulations  as
       may be posted and distributed from time to time.

           21. Plumbing  and  appliances  shall  be  used  only  for  the
       purposes  for which constructed, and  no sweeping, rubbish,  rags,
       or  other unsuitable material shall  be thrown or placed  therein.
       Any  stoppage  or  damage  resulting  to  any  such  fixtures   or
       appliances  from  misuse  on  the  part  of  Tenant  or   Tenant's
       officers,  agents,  servants,  and  employees  shall  be  paid  by
       Tenant.

           22. No signs,  posters, advertisements,  or notices  shall  be
       painted or affixed on any of the windows or doors, or other  parts
       of  the Building, except in  such color, size,  and style, and  in
       such  places, as shall be first  approved in writing by  Landlord.
       There  shall be no  obligation or duty  on Landlord  to give  such
       approval.  Building standard  suite identification  signs will  be
       prepared by  a sign writer, approved by Landlord. The cost of  the
       Building  standard sign  will be  paid by  Tenant. Landlord  shall
       have  the right to remove all  unapproved signs without notice  to
       Tenant,  at the expense of Tenant.  Directories will be placed  by
       Landlord  at Landlord's own expense,  inconspicuous places in  the
       Building. No other directories shall be permitted.

           23. No portion of the  Building shall be used for the  purpose
       for lodging rooms or any immoral or unlawful purposes.

           24. Vending machines or dispensing  machines of any kind  will
       not  be  placed in  the Leased  Premises  by Tenant  unless  prior
       written approval has been obtained from Landlord.

           25. Prior written approval, which shall be at Landlord's  sole
       discretion, must be obtained for installation of any solar  screen
       material,   window  shades,   blinds,  drapes,   awnings,   window
       ventilators, or  other similar equipment and any window  treatment
       of  any  kind  whatsoever.  Landlord  will  control  all  internal
       lighting  that may be  visible from the  exterior of the  Building
       and  shall  have the  right  to change  any  unapproved  lighting,
       without notice to Tenant, at Tenant's expense.

           26. Holidays as defined in this agreement include  New  Year's
     flay, Memorial Day, Independence Day, Labor flay, Thanksgiving,  and
     Christmas.

           27. Landlord  reserves the right to rescind any of these rules
     and make such other future rules and regulations as in the  judgment
     of Landlord  shall  from time  to time  be  Deeded for  the  safety,
     protection, care,  and cleanliness  of the  Building, the  operation
     thereof, the preservation of good order therein, and the  protection
     and comfort of its tenants,  their agents, employees, and  invitees,
     which rules when  made and notice thereof  given to a tenant,  shall
     be  binding  upon  him  in  like  manner  as  if  originally  herein
     prescribed.

           28. Tenant shall at all times keep  a  chair pad  under  every
     chair, which has rollers and is located in a carpeted area.

           29. Landlord will require all employees  and visitors to  wear
     identification badges as  prescribed by the  Landlord at all  times.
     Landlord shall exercise reasonable  discretion in refusing entry  to
     any person not wearing such identification.

<PAGE>


                                RIDER NO. 1

                          To Lease By and Between

               WESTERN ATLAS INTERNATIONAL INC., as Landlord

                                    and

                  CARRINGTON LABORATORIES INC., as Tenant


           1.   Cancellation Option. Either  party hereto may cancel  and
      terminate this lease  by giving the other  party three hundred  and
      sixty five (365)  days written notice  thereof; provided,  however,
      that Tenant ray  not cancel and terminate  this Lease if Tenant  is
      in  default  hereunder  either  when  the  cancellation  option  is
      exercised or on the date such cancellation is effective.

           2.   Parking.  Parking  facilities   are  available  for   the
      Building in an  uncovered parking area  in close  proximity to  the
      Building on a first-come first-served basis.  So long as Tenant  is
      not in default  under the terms  of this Lease,  Tenant shall  have
      the right  to  use such  facilities  on a  first-come  first-served
      basis for parking  by tenant and  Tenant's employees, visitors  and
      invitees without charge. Landlord,  however, reserves the right  at
      any time during the term of this lease to designate the area  which
      Tenant may use for parking of vehicles, which area shall be  larger
      than an  area large  enough  to park  forty-two (42)  vehicles,  In
      addition, Landlord  in  any case  will  designate six  (6)  parking
      spaces in reasonable  proximity of the  building for the  exclusive
      use of Tenant's executives.


<PAGE>

                                RIDER NO. 2

                          To Lease By and Between

              WESTERN ATLAS INTERNATIONAL. INC., as Landlord

                                    and

                  CARRINGTON LABORATORIES INC., as Tenant

                             Option to Extend

           Tenant at its option may extend the term of this Lease for  an
      additional three (3) years by  serving written notice thereof  upon
      landlord at  least six  (6)  months before  the expiration  of  the
      initial term hereof, provided that at  the time of such notice  and
      at the commencement  of such extended  term, there  shall exist  no
      event of default  as defined  in this  Lease. Upon  the service  of
      said notice, this Lease shall be extended without the necessity  of
      the execution of any further instrument or document. Such  extended
      term shall commence upon  the expiration date  of the initial  term
      of this  lease, expire  upon the  annual anniversary  of said  date
      three (3) years thereafter, and be  upon the same terms,  covenants
      and conditions  as provided  in this  Lease for  the initial  term,
      except that  the  Minimum Rent  payable  during the  extended  term
      shall be  at the  prevailing  rate as  determined by  Landlord  for
      comparable space in  the Las  Colinas Development  market area,  at
      the commencement of such extended term,

          Payment  of all additional rent  and other charges required  to
     be  made by Tenant as  provided in this lease  for the initial  term
     shall   continue  to  be  made   during  such  extended  term.   Any
     termination  of this lease during  the initial term shall  terminate
     all  rights of  extension hereunder, The  terms of  this option  are
     personal  to the Tenant  and will not  inure to the  benefit of  any
     assignee or subtenant of Tenant.

<PAGE>

                                EXHIBIT "A"

                         [FLOOR PLAN APPEARS HERE]


<PAGE>

                                EXHIBIT "C"

                          To Lease By and Between

              WESTERN ATLAS INTERNATIONAL, INC., as Landlord

                                    and

                  CARRINGTON LABORATORIES, INC, as Tenant


          Being  all of Las Colinas,  Area IV, First Installment  Revised
          Plot,  an addition to  the City of  Irving, Texas according  to
          the  Plat thereof recorded in Volume  81119, Page 0383, of  the
          Deed Records of Dallas County, Texas.

<PAGE>

                                EXHIBIT "D"

                            To Lease Agreement

                              By and Between

              WESTERN ATLAS INTERNATIONAL, INC., as Landlord
                                    and

                 CARRINGTON LABORATORIES, INC., as Tenant


         It is understood and agreed that:

         A.   PLANS AND  SPECIFICATIONS. Landlord agrees  to prepare  the
     initial plans  and  specifications  (the "Initial  Plans")  for  the
     completion of a dividing wall in the large open area shown generally
     on Schedule "1" attached  hereto and made a  part hereof to  provide
     for an  office for  the medical  director and  his secretary,  which
     improvements are hereinafter referred to as the "Tenant Finish", and
     to submit the Initial Plans to Tenant for Tenant's approval as  soon
     as practical  after  receiving Tenant's  construction  requirements,
     which construction  requirements  shall  be  submitted  to  Landlord
     within ten (10)  days after the  date of this  Lease. Tenant  shall,
     within fifteen (15) days  after receipt of  such Initial Plans  from
     Landlord, either approve or disapprove the sane: provided,  however,
     that should tenant request  any changes in  the Initial Plans  which
     vary from  Tenant's original  requirements,  any redrawing  of  such
     Initial Plans  shall  be  accomplished at  Tenant's  sole  cost  and
     expense. If Tenant  disapproves the  same, Tenant  shall specify  in
     reasonable  detail  the  reasons  for  any  such  disapproval.   Any
     redrawing of  the Initial  Plans or  changes therein  occasioned  by
     Tenant necessitated  because of  objections  which are  contrary  to
     Tenant's original requirements  submitted to  Landlord and/or  after
     Tenant's initial  approval shall  be accomplished  at Tenant's  sole
     cost and expense. The cost of such redrawing shall be paid by Tenant
     as additional rent  hereunder within  ten (10)  days after  tenant's
     receipt of Landlord's written demand therefor. Failure of Tenant  to
     respond within the aforesaid fifteen (15) day period shall be deemed
     to be approval of such Initial Plans. In the event the Initial Plans
     have not been approved by Landlord and Tenant within sixty (60) days
     from the date of this Lease, Landlord shall have the right to cancel
     and terminate this Lease.  The Initial Plans  which are approved  as
     aforesaid are hereinafter referred to as the Plans'.
<PAGE>
          B.  CONSTRUCTION. Landlord will construct the  Tenant Finish in
     the Leased Premises  with reasonable diligence  after the Plans  are
     approved pursuant to the terms of Paragraph A hereof.

          C.  OCCUPANCY AND RISK  OF LOSS.  It  Is understood and  agreed
     that Tenant  is occupying  the Leased  Premises under  the terms  of
     that  certain  Lease  dated  December  4,  1987,  as  amended   (the
     "Carrington Lease"),  which Lease  was  terminated by  Letter  dated
     January 1,  l99l  effective as  of  December 31,  1991.  The  Tenant
     Finish which  Landlord  has  agreed to  perform  hereunder  will  be
     performed during the term of the Carrington tease. Tenant agrees  to
     cooperate fully  with  Landlord in  the  performance of  the  tenant
     Finish in the  Leased Premises,  Tenant agrees  that Landlord  shall
     not be liable for any claims, losses or damage caused to persons  or
     property in  the  Leased  Premises during  the  performance  of  the
     Tenant finish unless such clams, losses  or damage is caused by  the
     malicious,  willful  or  grossly  negligent  acts  of  Landlord   or
     Landlord's employees or agents, Except  for the Tenant Finish  which
     landlord has agreed  to perform as  aforesaid, Tenant has  inspected
     the  Leased  Premises  and  accepts  the  same  as-is"  without  any
     warranty whatsoever, either express or implied: