Exhibit 10.6

                          SECOND LEASE AMENDMENT



      STATE OF TEXAS

      COUNTY OF DALLAS


           THIS  AGREEMENT  is  entered  into  as  of  the  23rd  day  of
      September, 1993, 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 F S S E T H:


           WHEREAS,  by   Lease  dated  August   30,  1991  (the   "Lease
      Agreement"), 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, by First  Lease Amendment, dated April 16, 1992  (the
      "First   Amendment")  Landlord  leased  to  Tenant  an   additional
      approximately  1,551 square feet of space  located in the  Building
      and described in the First Amendment; and

           WHEREAS,  the   Lease  Agreement  and   First  Amendment   are
      hereinafter collectively referred to as the "Lease"; and

           WHEREAS,  Landlord  and Tenant  desire  to add  an  additional
      approximately  862 square  feet  of space  to the  Leased  Premises
      (being   A-1047,  A-l048   and  A-1069)   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 24,146 square feet of  space
      as of the Effective Date.

           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
      January 1, 1994.

           1.   Area.  The figure 23,284 square feet set out in Paragraph
                1(a) of the Lease and wherever the figure appears in  the
                Lease is hereby deleted  and the figure 24.146 is  hereby
                substituted therefor.
<PAGE>
           2.   Minimum Rent.  The Minimum Rent  of $19,403.33 per  month
                set out in the  first (1st) line of Subparagraph 1(k)  of
                the Lease is increased  to $20,122.33 per month, and  the
                $21,828.75 per month set  out in the third (3rd) line  of
                Subparagraph 1(k)  of the  Lease is  hereby increased  to
                $22,637.75 per month.

           3.    Exhibit  "D" and Schedule  "1" to the  Lease are  hereby
                 deleted.

           4.   Operating  Costs.  The  base  year  for  operating   cost
                increases for the Additional Space only shall be  amended
                to mean Operating Costs for the 1993 calendar year.

           5.   Acceptance. Tenant  has inspected  the  Additional  Space
                "as-is" without any  warranty whatsoever, either  express
                or implied.


            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.

            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: _______________________



                               EXHIBIT   A


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