Exhibit 10.5



                           FIRST LEASE AMENDMENT
       STATE OF TEXAS

       COUNTY OF DALLAS


            THIS AGREEMENT  is  entered into  as  of the  16th    day  of
       April, 1992  by  and  between WESTERN  ATLAS  INTERNATIONAL  INC.,
       hereinafter   referred   to   as   "Landlord",   and    CARRINGTON
       LABORATORIES INC.,  hereinafter referred  to  as "tenant",  to  be
       effective on the Effective Date, as hereinafter defined.


                           W I T N E S S E T H:


            WHEREAS, by  Lease  dated  August  30,  1991  (the  "Lease"),
       Landlord leased  to Tenant  approximately  21,733 square  feet  of
       space in the  Building known  as the  Core Laboratories  Building,
       1300  East  Rochelle  Boulevard,  Irving,  Texas  75062-3963  (the
       "Building"); and

           WHEREAS,  Landlord has agreed  to lease  Tenant an  additional
       approximately 1,551 square feet of  space located in the  Building
       and described as follows:

            Room Nos.             Approximate Net Rentable Area
            ---------             -----------------------------

            A-1060 - Office              261 square feet
            A-1061 - Office              184 square feet
            A-1062 - Office              184 square feet
            A-1065 - Office              193 square feet
            A-1066 - Office              165 square feet
            A-1026 - Office              197 square feet
                                        -----------------
                          Sub-Total     1,184 square feet

            A-1070 - Conference          367 square feet
            Room
                                        -----------------
                              Total     1,551 square feet

       all of which space is shown  crosshatched on Exhibit "A"  attached
       hereto  and made a  part hereof for  all purposes (the "Additional
       Space"),  which  Additional  space will  effectively increase  the
       aggregate  square footage  covered by  the Lease to  approximately
       23,284 square feet of space as of the Effective Date.
<PAGE>
            NOW, THEREFORE, for and in consideration of the premises  and
       other good and valuable consideration the receipt and adequacy  of
       which is hereby acknowledged, the  parties hereto do hereby  agree
       that the Lease is amended and modified as follows effective as  of
       the first to  occur of (i)  the date Landlord  notifies Tenant  in
       writing  that  the  Tenant  finish  has  been  completed  in   the
       Additional Space  in  accordance with  the  terms of  Exhibit  "B"
       attached hereto and made a part  hereof for all purposes; or  (ii)
       on the date Landlord would have completed the Tenant Finish in the
       Additional Space in accordance with Exhibit "B" hereof except  for
       delays caused by Tenant or by the agents, employees or contractors
       of Tenant; or (iii) on the  date Tenant actually takes  possession
       of all or any part  of the Additional Space,  or (iv) May 1  1992,
       the first of which dates is  herein referred to as the  "Effective
       Date":

       1.   Area. The  figure 21,733  square feet  set out  in  Paragraph
            l(a) of  the Lease  and wherever  the figure  appears in  the
            Lease is  hereby  deleted and  the  figure 23,284  is  hereby
            substituted therefor.

       2.   Minimum Rent. The  Minimum Rent of  $18,110.83 per month  set
            out in  the first  (lst)  line of  Subparagraph 1(k)  of  the
            Lease  is  increased  to   $19,403.33  per  month,  and   the
            $20,374.69 per  month set  out  in the  third (3rd)  line  of
            Subparagraph  1(k)  of  the  Lease  is  hereby  increased  to
            $21,828.75 per  month. Minimum  Rent for  the calendar  month
            when the  Effective  Date occurs  shall  be prorated  on  the
            basis of the number of days in that calendar month.

       3.   Operating Costs. The date "January 1, 1992" contained in  the
            third line of the third grammatical paragraph of Paragraph  8
            is hereby deleted  and the date "January  1, 1993" is  hereby
            substituted therefor.

       4.   Construction Landlord shall  construct the  Tenant Finish  in
            the Additional Space in accordance with the terms of  Exhibit
            "B" hereto.

       The Lease as hereby  amended is hereby  ratified and confirmed  as
  being in full force and effect. This Agreement shall be binding on  the
  parties hereto and  their respective successors  and assigns:  subject,
  however, to the terms of the Lease as hereby amended.

<PAGE>
       EXECUTED as of the date first hereinabove set out.

                                LANDLORD:

                                WESTERN ATLAS INTERNATIONAL, INC.

                                BY: /s/
                                   __________________________

                                      Printed Name:
                                      Title:

                                TENANT:

                                CARRINGTON LABORATORIES, INC.

                                BY:   /s/
                                  __________________________

                                      Printed Name:
                                      Title:


<PAGE>

                                 EXHIBIT A




                        [ FLOOR PLAN APPEARS HERE ]




<PAGE>


                                EXHIBIT "B"

                to First Lease Amendment (the "Agreement")
                              By and Between

              WESTERN ATLAS INTERNATIONAL, INC. , as Landlord
                                    and

                 CARRINGTON LABORATORIES. INC., as Tenant


            It is understood and agreed that:

             A.   Landlord agrees at  Landlord's  sole  cost and  expense
        to construct  (i)  approximately  fifteen  (l5)  linear  feet  of
        demising wall, taped, bedded and painted  with one (1) coat of  a
        Building standard paint matching the existing walls, and (ii) one
        (1) Building standard emergency exit door with Building  standard
        hardware to create an exit to the Building lobby and entry to the
        A-1 level of the Building. The work hereinbefore provided for  is
        referred to in this Agreement as  the "Tenant Finish". All  other
        parts of the Additional Space have  been inspected by Tenant  and
        are accepted  "as-is"  without any  warranty  whatsoever,  either
        express or implied.

             B.   ACCEPTANCE: tenant shall within twenty (20) days  after
        the Effective Date provide Landlord  with a so-called punch  list
        of incomplete  work and  if such  work is  Landlord's  obligation
        hereunder,  such  work  shall  be  completed  by  Landlord   with
        reasonable diligence under the  circumstances. Any Tenant  Finish
        not listed  on  the  punch list  shall  be  deemed  accepted  and
        completed in accordance with the terms hereof.

             C. If Landlord shall be delayed in substantially  completing
        the Tenant Finish as a result of:

             (a)  Tenant's failure  to promptly  and timely  furnish  any
                  information required by Landlord; or

             (b)  Tenant's   request   for    materials,   finishes    or
                  installations other than Landlord's Building  Standard;
                  or

             (c)  the performance  of  work by  or  on behalf  of  Tenant
                  during the  early  occupancy  period  provided  for  in
                  Paragraph D  hereof by  a person,  firm or  corporation
                  employed by Tenant and the  completion of said work  by
                  said person,  firm or  corporation (all  such  persons,
                  firms or corporations being subject to the approval  of
                  Landlord);

        then the Effective  Date shall be  accelerated by  the number  of
        days of such delays.
<PAGE>
             D.  Landlord will permit Tenant and its agents to enter  the
       Additional Space prior to the Effective Date in order that  Tenant
       may perform through its  own contractors (to be first approved  by
       Landlord) such other work and decorations as Tenant may desire  at
       the  same time  that  Landlord's contractors  are working  in  the
       Additional  Space. The  foregoing license  to enter  prior to  the
       Effective Date, however, is conditioned upon Tenant's workmen  and
       mechanics working  in harmony and not  interfering with the  labor
       employed by  Landlord, Landlord's mechanics  or contractors or  by
       any  other tenant or  their contractors. Such  license is  further
       conditioned  upon  Worker's  Compensation  and  public   liability
       insurance for  bodily injury and property  damage, all in  amounts
       and with  companies and on forms  satisfactory to Landlord,  being
       provided  and  at all  times  maintained by  Tenant's  contractors
       engaged in the performance  of the work, and certificates of  such
       insurance  being furnished to  Landlord prior  to proceeding  with
       the  work. If at  any time such  entry shall  cause disharmony  or
       interference therewith, this license may be withdrawn by  Landlord
       upon forty-eight (48)  hours written notice to Tenant. Such  entry
       conditions  shall  be  deemed  to  be  under  all  of  the  terms,
       covenants, provisions  and conditions of the  Lease, except as  to
       the covenant to  pay the additional Minimum Monthly Rent  provided
       for  in Paragraph 2  of this Agreement  unless otherwise  provided
       for  herein. Landlord  shall not  be  liable in  any way  for  any
       injury,  loss  or  damage  which may  occur  to  any  of  Tenant's
       decorations or installations so made prior to the Effective  Date,
       the  same being solely  at Tenant's  risk, and  Tenant shall  hold
       Landlord harmless  from any claim, demand  or action arising  from
       activities of Tenant's contractors, workmen or mechanics.