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                                                               EXHIBIT 10.13

[BANK ONE LOGO]

                               PROMISSORY NOTE

<TABLE>
<S>            <C>            <C>           <C>          <C>       <C>             <C>          <C>          <C>
PRINCIPAL      LOAN DATE      MATURITY      LOAN NO      CALL      COLLATERAL      ACCOUNT      OFFICER      INITIALS
$500,000.00    05-06-1996     11-06-1996                 247259    020             1766452613   82744

References in the shaded area are for Lender's use only and do not limit the applicability of this document to 
any particular loan or item.

</TABLE>

BORROWER:   THE COMPANY DOCTOR                   LENDER:   BANK ONE, TEXAS, N.A.
            1200 E. COPELAND, SUITE 100                    ARLINGTON-BOWEN
            ARLINGTON, TX 76011                            1301 S. BOWEN RD.
                                                           ARLINGTON, TX 76013

================================================================================

PRINCIPAL AMOUNT:  $500,000.00                        DATE OF NOTE:  MAY 6, 1996

PROMISE TO PAY. For value received, the undersigned and if more than one, each
of them, jointly and severally ("Borrower") promises to pay to Bank One, Texas,
N.A. ("Lender"), or order, in lawful money of the United States of America, the
principal amount of Five Hundred Thousand & 00/100 Dollars ($500,000.00),
together with interest at the rate of 6.750% per annum on the unpaid principal
balance from the date advanced until maturity.

PAYMENT. This Note shall be payable as follows: Interest shall be due and
payable monthly as it accrues, commencing on June 6, 1996 and continuing on the
same day of each month thereafter during the term of this Note, and the
outstanding principal balance of this Note, together with all accrued but unpaid
interest, shall be due and payable on November 6, 1996. Interest on this Note
is computed on a 365/360 simple interest basis; that is by applying the ratio of
the annual interest rate over a year of 360 days, multiplied by the outstanding
principal balance, multiplied by the actual number of days the principal balance
is outstanding, unless such calculation would result in a usurious rate, in 
which case interest shall be calculated on a per diem basis of a year of 365 or
366 days, as the case may be. Borrower will pay Lender at Lender's address shown
above or at such other place as Lender may designate in writing. If any payment
of principal of or interest on this Note shall become due on a day which is not
a Business Day, such payment shall be made on the next succeeding Business Day
and any such extension of time shall be included in computing interest in
connection with such payment. As used herein, the term "BUSINESS DAY" shall mean
any day other than a Saturday, Sunday or any other day on which national banking
associations are authorized to be closed. Unless otherwise agreed or required by
applicable law, payments will be applied first to accrued unpaid interest, then
to principal, and any remaining amount to any unpaid collection costs. The books
and records of Lender shall be prima facie evidence of all outstanding principal
of and accrued but unpaid interest on this Note. If this Note is governed by or
is executed in connection with a loan agreement, this Note is subject to the
terms and provisions thereof.

PREPAYMENT. Borrower may pay without premium or penalty all or a portion of the
principal amount owed hereunder earlier than it is due. All prepayments shall be
applied to the indebtedness owing hereunder in such order and manner as Lender
may from time to time determine in its sole discretion.

POST MATURITY RATE. Upon an Event of Default or at maturity, whether by
acceleration or otherwise, all unpaid principal of this Note shall bear interest
at the maximum rate permitted by law. If applicable law ceases to provide for
such a maximum rate, the maximum rate shall be equal to 18.000% per annum.

DEFAULT. Borrower will be in default if any of the following happens: (a)
Borrower fails to make any payment of principal or interest when due under this
Note or any other indebtedness owing now or hereafter by Borrower to Lender; (b)
failure of Borrower or any other party to comply with or perform any term,
obligation, covenant or condition contained in this Note or in any other
promissory note, credit agreement, loan agreement, guaranty, security agreement,
mortgage, deed of trust or any other instrument, agreement or document, whether
now or hereafter existing, executed in connection with this Note (the Note and
all such other instruments, agreements, and documents shall be collectively
known herein as the "Related Documents"); (c) Borrower defaults under any loan,
extension of credit, security agreement, purchase or sales agreement, or any
other agreement, in favor of any other creditor or person that may materially
affect any of Borrower's property or Borrower's ability to repay this Note or
perform Borrower's obligations under this Note or any of the Related Documents;
(d) any representation or statement made or furnished to Lender herein, in
any of the Related Documents or in connection with any of the foregoing is false
or misleading in any material respect; (e) Borrower or any other party liable
for the payment of this Note, whether as maker, endorser, guarantor, surety or
otherwise, becomes insolvent or bankrupt, has a receiver or trustee appointed
for any part of its property, makes an assignment for the benefit of its
creditors, or any proceeding is commenced either by any such party or against it
under any bankruptcy or insolvency laws; (f) the occurrence of any event of
default specified in any of the other Related Documents or in any other
agreement now or hereafter arising between Borrower and Lender; (g) the 
occurrence of any event which permits the acceleration of the maturity of any
indebtedness owing now or hereafter by Borrower to any third party; or (h) the
liquidation, termination, dissolution, death or legal incapacity of Borrower or
any other party liable for the payment of this Note, whether as maker, endorser,
guarantor, surety, or otherwise;

LENDER'S RIGHTS. Upon default, Lender may at its option, without further notice
or demand (i) declare the entire indebtedness, including the unpaid principal
balance on this Note, all accrued unpaid interest, and all other amounts, costs
and expenses for which Borrower is responsible under this Note or any other
Related Document, immediately due, (ii) refuse to advance any additional amounts
under this Note, (iii) foreclose all liens securing payment hereof, (iv) pursue
any other rights, remedies, and recourses available to the Lender, including
without limitation, any such rights, remedies or recourses under Related
Documents, at law or in equity, or (v) pursue any combination of the foregoing.
The rights, remedies and recourses of Lender, as provided in this Note and in 
the other Related Documents, shall be cumulative and concurrent and may be 
pursued separately, successively or together as often as occasion therefore 
shall arise, at the sole discretion of Lender. The acceptance by Lender of any 
payment under this Note which is less than the payment in full of all amounts 
due and payable at the time of such payment shall not (i) constitute a waiver 
of or impair, reduce, release or extinguish any right, remedy or recourse of 
Lender, or nullify any prior exercise of any such right, remedy or recourse, 
or (ii) impair, reduce, release or extinguish the obligations of any party 
liable under any of the Related Documents as originally provided herein or 
therein. Lender may hire an attorney to help collect this Note if Borrower 
does not pay, and Borrower will pay Lender's reasonable attorneys' fees and all
other costs of collection. To the extent interest is not paid on or before the 
fifth day after it becomes due and payable, Lender may, at its option, add such
accrued but unpaid interest to the principal balance of this Note. This Note has
been delivered to Lender and is performable in Tarrant County, Texas. Courts 
within the State of Texas have jurisdiction over any dispute arising under or
pertaining to this Note and venue for such dispute shall be in Tarrant County,
Texas. THIS NOTE SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS
OF THE STATE OF TEXAS AND APPLICABLE FEDERAL LAWS.

PURPOSE. Borrower agrees that no advances under this Note shall be used for
personal, family, or household purposes and that all advances hereunder shall be
used solely for business, commercial, agricultural or other similar purposes.

GENERAL PROVISIONS. NOTICE: Under no circumstances (and notwithstanding any
other provisions of this Note) shall the interest charged, collected, or
contracted for on this Note exceed the maximum rate permitted by law. The term
"maximum rate permitted by law" as used in this Note means the greater of (a)
the maximum rate of interest permitted under federal or other law applicable to
the indebtedness evidenced by this Note, or (b) the higher, as of the date of
this Note, of the "Indicated Rate Ceiling" or the "Quarterly Ceiling" as
referred to in Article

  

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prepayments  __________________________________________________________________

_______________________________________________________________________________

sole discretion.

POST MATURITY RATE.  Upon an Event of Default or at maturity, whether by
acceleration or otherwise, all unpaid principal of this Note shall bear
interest at the maximum rate permitted by law.  If applicable law ceases to
provide for such a maximum rate, the maximum rate shall be equal to 18.000% per
annum.

DEFAULT.  Borrower will be in default if any of the following happens:  (a)
Borrower fails to make any payment of principal or interest when due under
this Note or any other indebtedness owing now or hereafter by Borrower to
Lender; (b) failure of Borrower or any other party to comply with or perform
any term, obligation, covenant or condition contained in this Note or in any
other promissory note, credit agreement, loan agreement, guaranty, security
agreement, mortgage, deed of trust or any other instrument, agreement or
document, whether now or hereafter existing, executed in connection with this
Note (the Note and all such other instruments, agreements, and documents shall
be collectively known herein as the "Related Documents"); (c) Borrower defaults
under any loan, extension of credit, security agreement, purchase or sales
agreement or any other agreement, in favor of any other creditor or person that
may materially affect any of Borrower's property or Borrower's or ability to
repay this Note or perform Borrower's obligations under this Note or any of the
Related Documents; (d) any representation or statement made or furnished to
Lender herein, in any of the Related Documents or in connection with any of the
foregoing is false or misleading in any material respect; (e) Borrower any
other party liable for the payment of this Note, whether as maker, endorser,
guarantor, surety of otherwise, becomes insolvent or bankrupt, has a receiver
or trustee appointed for any part of its property, makes an assignment for the
benefit of its creditors, or any proceeding is commenced either by any such
party or against it under any bankruptcy or insolvency laws; (f) the occurrence
of any event of default specified in any of the other Related Documents or in
any other agreement now or hereafter arising between Borrower and Lender; (g)
the occurrence of any event which permits the acceleration of the maturity of
any indebtedness owing now or hereafter by Borrower to any third party; or (h)
the liquidation, termination, dissolution, death or legal incapacity of
Borrower or any other party liable for the payment of this Note, whether as
maker, endorser, guarantor, surety, or otherwise;

LENDER'S RIGHTS.  Upon default, Lender may at its option, without further
notice or demand (i) declare the entire indebtedness, including the unpaid
principal balance on this Note, all accrued unpaid interest, and all other
amounts, costs and expenses for which Borrower is responsible under this Note
or any other Related Document, immediately due, (ii) refuse to advance any
additional amounts under this Note, (iii) foreclose all liens securing payment
hereof, (iv) pursue any other rights, remedies and recourses available to the
Lender, including without limitation, any such rights, remedies or recourses
under the Related Documents, at law or in equity, or (v) pursue any combination
of the foregoing.  The rights, remedies and recourses of Lender, as provided in
this Note and in the other Related Documents, shall be cumulative and
concurrent and may be pursued separately, successively or together as often as
occasion therefore shall arise, at the sole discretion of Lender.  The
acceptance by Lender of any payment under this Note which is less than the
payment in full of all amounts due and payable at the time of such payment
shall not (i) constitute a waiver of or impair, reduce, release or extinguish
any right, remedy or recourse of Lender, or nullify any prior exercise of any
such right, remedy or recourse, or (ii) impair, reduce, release or extinguish
the obligations of any party liable under any of the Related Documents as
originally provided herein or therein.  Lender may hire an attorney to help
collect this note if Borrower does not pay, and Borrower will pay Lender's
reasonable attorneys' fees and all other costs of collection.  To the extent
interest is not paid on or before the fifth day after it becomes due and
payable, Lender may, at its option, add such accrued but unpaid interest to the
principal balance of this Note.  This Note has been delivered to Lender and is
performable in Tarrant County, Texas.  Courts within the State of Texas have
jurisdiction over any dispute arising under or pertaining to this Note and
venue for such dispute shall be in Tarrant County, Texas.  THIS NOTE SHALL BE
GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF TEXAS AND
APPLICABLE FEDERAL LAWS.

PURPOSE.  Borrower agrees that no advances under this Note shall be used for
personal, family, or household purposes and that all advances hereunder shall
be used solely for business, commercial, agricultural or other similar
purposes.

GENERAL PROVISIONS.  NOTICE:  Under no circumstances (and notwithstanding any
other provisions of this Note) shall the interest charged, collected, or
contracted for on this Note exceed the maximum rate permitted by law.  The term
"maximum rate permitted by law" as used in this Note means the greater of (9a)
the maximum rate of interest permitted under federal or other law applicable to
the indebtedness evidenced by this Note, or (b) the higher, as of the date of
this Note, of the "Indicated Rate Ceiling" or the "Quarterly Ceiling" as
referred to in Article 5069-1.04(a)(1) and Article 5069-1.04(a)(2)
respectively, V.T.C.S.  If any part of this Note cannot be enforced, this fact
will not affect the rest of the Note.  In particular, this section means (among
other things) that Borrower does not agree or intend to pay, and Lender does
not agree or intend to contract for, charge, collect, take, reserve or receive
(collectively referred to herein as "charge or collect"), any amount in the
nature of interest or in the nature of a fee for this loan, which would in any
way or event (including demand, prepayment, or acceleration) cause Lender to
charge or collect more for this loan than the maximum Lender would be
permitted to charge or collect by federal law or the law of the State of Texas
(as applicable).  Any such excess interest or unauthorized fee shall, instead
of anything stated to the contrary, be applied first to reduce the principal
balance of this loan, and when the principal has been paid in full, be refunded
to Borrower.  The right to accelerate maturity of sums due under this Note does
not include the right to accelerate any interest which has not otherwise
accrued on the date of such acceleration, and Lender does not intend to charge
or collect any unearned interest in the event of acceleration.  All sums paid
or agreed to be paid to Lender for the use, forbearance or detention of sums
due hereunder shall, to the extent permitted by applicable law, be amortized,
prorated, allocated and spread throughout the full term of the loan evidenced
by this Note until payment in full so that the rate or amount of interest on
account of the loan evidenced hereby does not exceed the applicable usury
ceiling.  Lender may delay or forego enforcing any of its rights or remedies
under this Note without losing them.  Borrower and any other person who signs,
guarantees or endorses this Note, to the extent allowed by law, severally waive
presentment, demand for payment, protest, notice of protest, notice of
dishonor, notice of intent to accelerate the maturity of this Note, notice of
acceleration of the maturity of this Note, diligence in enforcement and
indulgences of every kind.  Upon any change in the terms of this Note, and
unless otherwise expressly stated in writing, no party who signs this Note,
whether as maker, guarantor, accommodation maker or endorser, shall be released
from liability.  All such parties agree that Lender may renew or extend
(repeatedly and for any length of time) this Note, or release any party or
guarantor or collateral; or impair, fail to realize upon or perfect Lender's
security interest in the collateral without the consent of or notice to anyone.
All such parties also agree that Lender may modify this Note without the
consent of or notice to anyone other than the party with whom the modification
is made.  Borrower agrees to provide to Lender such further financial
information with respect to Borrower as Lender may reasonably request from time
to time, including, without limitation, financial statements in form and detail
satisfactory to Lender.

<PAGE>   3
05-06-1996                      PROMISSORY NOTE                           PAGE 2
LOAN NO                           (CONTINUED)           
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PRIOR TO SIGNING THIS NOTE, BORROWER READ AND UNDERSTOOD ALL THE PROVISIONS OF
THIS NOTE. BORROWER AGREES TO THE TERMS OF THE NOTE AND ACKNOWLEDGES RECEIPT OF
A COMPLETED COPY OF THE NOTE.

BORROWER:

THE COMPANY DOCTOR

By: /s/ FRED G. PARRISH
   -----------------------------------------
   FRED G. PARRISH, CHIEF OPERATING OFFICER
   AND VICE PRESIDENT