Exhibit 10.4

      [THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
      UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"), OR ANY STATE
      SECURITIES LAWS AND NEITHER SUCH SECURITIES NOR ANY INTEREST THEREIN MAY
      BE OFFERED, SOLD, PLEDGED, ASSIGNED OR OTHERWISE TRANSFERRED EXCEPT (1)
      PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT
      AND APPLICABLE STATE SECURITIES LAWS OR (2) PURSUANT TO AN AVAILABLE
      EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND
      APPLICABLE STATE SECURITIES LAWS, IN WHICH CASE THE HOLDER MUST, PRIOR TO
      SUCH TRANSFER, FURNISH TO THE COMPANY AN OPINION OF COUNSEL, WHICH COUNSEL
      AND OPINION ARE REASONABLY SATISFACTORY TO THE COMPANY, THAT SUCH
      SECURITIES MAY BE OFFERED, SOLD, PLEDGED, ASSIGNED OR OTHERWISE
      TRANSFERRED IN THE MANNER CONTEMPLATED PURSUANT TO AN AVAILABLE EXEMPTION
      FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND APPLICABLE
      STATE SECURITIES LAWS.]

             Right to Purchase up to [___] Shares of Common Stock of
    CASTLE & MORGAN HOLDINGS, INC. (subject to adjustment as provided herein)

                          COMMON STOCK PURCHASE WARRANT

No. W2006-[__]                                         Issue Date:  May 24, 2006

      Castle & Morgan Holdings, Inc., a corporation organized under the laws of
the State of Delaware (the "Company"), hereby certifies that, for value
received, [_________], or assigns (the "Holder"), is entitled, subject to the
terms and conditions set forth below, to purchase from the Company (as defined
herein) from and after the Issue Date of this Warrant and at any time or from
time to time before 5:00 p.m., New York time, through the close of business on
the date that is ten (10) years from the Date of Commencement (as defined below)
(the "Expiration Date"), up to [______] fully paid and nonassessable shares of
Common Stock (as hereinafter defined), $0.0001 par value per share, at the
applicable Exercise Price per share (as defined below). The number and character
of such shares of Common Stock and the applicable Exercise Price per share are
subject to adjustment as provided herein. This Warrant is being exchanged on the
Issue Date noted above for a like warrant agreement with respect to shares of
Osteologix A/S, which warrant agreement is on the same terms and conditions as
this Warrant and with respect to which the Holder has agreed to the cancellation
thereof in consideration of the issuance of this Warrant.

      As used herein the following terms, unless the context otherwise requires,
have the following respective meanings:

            1. The term "Bad Leaver Scenario" shall mean the Holder is
      terminated by the Company from his position as [____] as a consequence of
      his (or his de facto controlled company (companies)) material breach of
      this Warrant or other agreements between the Holder (or his de facto
      controlled company/companies) and the Company.
<PAGE>

            2. The term "Company" shall include Castle & Morgan Holdings, Inc.
      and any corporation which shall succeed, or assume the obligations of,
      Castle & Morgan Holdings, Inc. hereunder.

            3. The term "Common Stock" includes (i) the Company's Common Stock,
      par value $0.0001 per share; and (ii) any other securities into which or
      for which any of the securities described in the preceding clause (i) may
      be converted or exchanged pursuant to a plan of recapitalization,
      reorganization, merger, sale of assets or otherwise.

            4. The term "Date of Commencement" has the meaning set forth in
      Section 2.1.

            5. The term "Exercise Period" has the meaning set forth in Section
      3.1.

            6. The "Exercise Price" applicable under this Warrant shall be
      $1.03.

            7. The "Fair Market Value" of a share of Common Stock as of a
      particular date (the "Determination Date") shall mean the value of the
      Common Stock as determined in good faith and consistent with applicable
      law by the Company's Board of Directors, subject to confirmation by an
      independent appraisal at the option of the Holder.

            8. The term "Other Securities" refers to any stock (other than
      Common Stock) and other securities of the Company or any other person
      (corporate or otherwise) which the holder of the Warrant at any time shall
      be entitled to receive, or shall have received, on the exercise of the
      Warrant, in lieu of or in addition to Common Stock, or which at any time
      shall be issuable or shall have been issued in exchange for or in
      replacement of Common Stock or Other Securities pursuant to Section 5 or
      otherwise.

      a. Exercise of Warrant.

            i) Number of Shares Issuable upon Exercise. From and after the date
hereof through and including the Expiration Date, the Holder shall be entitled
to receive, upon exercise of this Warrant in whole or in part, by delivery of an
original or fax copy of an exercise notice in the form attached hereto as
Exhibit A (the "Exercise Notice"), up to that number of shares of Common Stock
of the Company referred to above, subject to adjustment pursuant to Sections 4
and 5.

            ii) Condition to Exercise. As a consequence of the above, the
Company and the Holder have agreed that the Holder's right to exercise Warrants
shall be conditional upon the Holder in the Period of Acquisition (as defined in
Section 2.1 below) being [____]. On the Holder's resignation as [____], the
Parties agree that the Holder's right to exercise Warrants shall be conditional
on the circumstances under which the Holder ceases his position as [____].

            iii) Good Leaver. In the event of the termination of the Holder's
employment with the Company, if the Holder is not terminated by the Company
under a Bad Leaver Scenario, and provided that an agreement regarding
consummation of a Liquidity Event, as described below in Sections 1.5, 1.6, 1.7
and 4.2, has been entered into, the Holder shall be entitled to exercise all
Warrants represented hereby in the relevant Exercise Period, subject to Section
1.8 (a "Good Leaver Scenario").


                                       2
<PAGE>

            iv) Liquidity Events. Situations as described in Sections 1.5, 1.6,
1.7 and 4.2 are individually and collectively referred to as "Liquidity
Event(s)". The relevant criterion - agreed between the parties - of a Liquidity
Event's commencement is that the Company's securities or most important assets
shall be sold/licensed against payment in cash or payment with securities
admitted for sale on a regulated market place on the basis of one aggregate
transaction. The takeover shall be deemed as one aggregate transaction,
notwithstanding whether the takeover takes place on several occasions, if the
takeover arises out of the same agreement.

            v) Acquisition of Shares. Where one/more purchaser(s) who is
independent of the principal shareholders of the Company (hereinafter referred
to as the "Purchaser") purchases for cash or payment in securities admitted for
sale on a regulated market place in one aggregate transaction more than 50% of
the outstanding shares of Common Stock of the Company, the Holder may exercise
all Warrants represented hereby. The takeover shall be deemed as one aggregate
transaction, notwithstanding whether the takeover takes place in several
occasions, if the takeover arises out of the same agreement. To the extent the
Holder exercises the Warrants, the Holder shall be obliged and entitled to sell
the shares subscribed for to the Purchaser or to a purchaser designated by the
Purchaser against payment in cash per share equal to the average purchase price
per share paid by the Purchaser for acquired shares of the same class in
connection with the Liquidity Event, notwithstanding the distribution on classes
of shares. In the event of purchases as described in this clause 1.5, an
Exercise Period shall be established with opening day not later than 4 weeks
after such a purchase agreement has been entered into between the parties in
such a transfer, where the Holder in accordance with Section 1.3 above in a Good
Leaver Scenario shall be entitled to exercise all Warrants represented hereby.
Warrants not exercised by the Holder in connection with such Liquidity Event
during the Exercise Period shall lapse without further notice and without any
compensation.

            vi) Distribution of Dividend. In the event of distribution of
dividend in the excess of the Exercise Price plus an annual return of 50% from
the Date of Commencement per share, an Exercise Period shall be established with
opening day not later than 4 weeks prior to such decision to distribute such
dividend has been finally adopted by the board of directors of the Company.
During this Exercise Period, provided the Holder shall in accordance with
Section 1.3 be in a Good Leaver Scenario, be entitled to exercise all Warrants
represented hereby.

            vii) Admission of Securities for Sale on a Regulated Market Place.
Where the Company's securities are admitted for sale on a regulated market
place, an Exercise Period shall be established with opening day not later than
four weeks after the first day when the securities may be traded on the
regulated market place, where the Holder may exercise all vested Warrants.
Conditional upon the Holder not having terminated under a Bad Leaver Scenario,
the daily vesting of [____] Warrants mentioned in clause 2.1 shall be amended so
that the Holder in a period of 365 days from the date of the Company's
securities being admitted for sale on a regulated market place (first trade
date) daily acquires a proportionate right to the remaining unvested Warrants
based on 365 days/year. This amendment of the Period of Acquisition shall only
apply if the Period of Acquisition hereby is reduced to less than 912 days. In
the Liquidity Event mentioned in this Section 1.7, an Exercise Period shall be
established the day after any publication of the Company's announcement of
financial results with opening day on that day, where the Holder may exercise
the vested, non-exercised Warrants to which the Holder has acquired a right of
exercise. The Holder has agreed to fully comply with any and all lock-up
arrangements applicable to some or all of the Company's securities, including
Warrants (whether exercised or not), in connection with an admission of some or
all of the Company's securities to be traded on a regulated market place.


                                       3
<PAGE>

            viii) Termination of Holder's Employment. In the event that the
Holder's employment with the Company terminates, notwithstanding the reason, and
at the time of termination the Holder holds non-exercised Warrants, all unvested
Warrants shall lapse and an Exercise Period shall be established commencing on
the Date of Termination during which the Holder shall be entitled to exercise
any vested, non-exercised Warrants. The Exercise Period shall be the normal
14-day period provided under Section 3.1, unless the Holder has been terminated
under a Bad Leaver Scenario, in which case the Exercise Period shall be the
3-month period provided under Section 3.6. If the Holder has voluntarily
resigned or if the Holder has been terminated under a Bad Leaver Scenario,
Warrants not exercised by the Holder during the applicable Exercise Period shall
lapse without further notice and without any compensation at the end of the
applicable Exercise Period. If the Holder is involuntarily terminated under a
Good Leaver Scenario, the Holder's vested Warrants shall not lapse at the end of
the Exercise Period and may be exercised in subsequent Exercise Periods as
provided under Section 3.4.

      b. Conditions for Vesting of Warrants.

            i) Vesting. The number of Warrants that the Holder is entitled to
exercise according to the situations described in Section 1 depends on the
Holder's continued position as [_____] of the Company. Conditional on the
Holder's continued position as [_____] of the Company, the Holder shall acquire
a right based on 365 days/year to exercise 1/912 (to be rounded up, if exercise
is to take place before full vesting has occurred, provided that no more than a
total number of Warrants specified above can be vested hereunder) of the
Warrants represented hereby per day beginning on [_____] (hereinafter referred
to as the "Date of Commencement"), [provided however that on the Date of
Commencement, the first 8,690 Warrants shall vest immediately and the balance of
the 52,000 Warrants shall vest over the 912 day period]. Thus, all Warrants
represented hereby will vest by the 912th day after the Date of Commencement
(the "Period of Acquisition").

            ii) Timing. The "Date of Termination" shall mean the date of the
cessation of the Holder's employment with Company for any reason whatsoever,
whether voluntary or involuntary, including as a result of the Holder's
retirement, disability or death and notwithstanding whether the Holder might be
given pay in lieu of prior notice of such termination.

            iii) Cessation of Vesting. From and after the Date of Termination,
no further vesting of Warrants shall take place.

      c. Procedure for Exercise.


                                       4
<PAGE>

            i) Exercise Periods. The Holder may exercise vested Warrants in the
relevant Exercise Periods (hereinafter referred to as the "Exercise Period")
specified in Sections 1.5, 1.6, 1.7, 1.8 and 4.2. Except as specifically
provided herein, the Exercise Periods commence on the specified opening day and
continue for the following 14 days. The Company shall in writing notify the
Holder of the time of any Exercise Period not later than 2 weeks before the
relevant opening day.

            ii) Delivery of Stock Certificates, Etc., on Exercise. The Company
agrees that the shares of Common Stock purchased upon exercise of this Warrant
shall be deemed to be issued to the Holder as the record owner of such shares as
of the close of business on the date on which this Warrant shall have been
surrendered and payment made for such shares in accordance herewith. As soon as
practicable after the exercise of this Warrant in full or in part, and in any
event within three (3) business days thereafter, the Company at its expense
(including the payment by it of any applicable issue taxes) will cause to be
issued in the name of and delivered to the Holder, or as such Holder (upon
payment by such Holder of any applicable transfer taxes) may direct in
compliance with applicable securities laws, a certificate or certificates for
the number of duly and validly issued, fully paid and nonassessable shares of
Common Stock (or Other Securities) to which such Holder shall be entitled on
such exercise, plus, in lieu of any fractional share to which such holder would
otherwise be entitled, cash equal to such fraction multiplied by the then Fair
Market Value of one full share, together with any other stock or other
securities and property (including cash, where applicable) to which such Holder
is entitled upon such exercise pursuant to Section 1 or otherwise. Where the
Holder exercises Warrants, the Holder shall be obliged to accept at any time an
existing shareholders' agreement regarding the Company.

            iii) Exercise. Payment may be made either in cash or by certified or
official bank check payable to the order of the Company equal to the applicable
aggregate Exercise Price for the number of Common Shares specified in such
Exercise Notice (as such exercise number shall be adjusted to reflect any
adjustment in the total number of shares of Common Stock issuable to the Holder
per the terms of this Warrant) and the Holder shall thereupon be entitled to
receive the number of duly authorized, validly issued, fully-paid and
non-assessable shares of Common Stock (or Other Securities) determined as
provided herein.

            iv) Lapse. In the event Warrants have vested and a Bad Leaver
Scenario does not exist, the vested Warrants shall be exercised on one or more
occasion(s) until July 1, 2013 during the Exercise Periods described in Section
3.1. Warrants which the Holder does not exercise during one of these Exercise
Periods shall lapse without further notice and without any compensation.

            v) Financial Statements. In connection with the publication of the
Company's financial statements and annual accounts, an Exercise Period shall be
established in which period all or a part of the vested Warrants may be
exercised, unless otherwise agreed in Sections 1.7 and 3.6.

            vi) Bad Leaver. In the event that the Holder's position as [ ]
terminates as a result of a Bad Leaver Scenario, a three months' Exercise Period
shall commence on the date of the resignation, where the Holder shall be
entitled to exercise vested, non-exercised Warrants. Warrants not exercised by
the Holder during this Exercise Period shall lapse without further notice and
without any compensation.


                                       5
<PAGE>

      d. Effect of Reorganization, Etc.; Adjustment of Exercise Price.

            i) Reorganization, Consolidation, Merger, Etc. In case at any time
or from time to time, the Company shall (a) effect a reorganization, (b)
consolidate with or merge into any other person, or (c) transfer all or
substantially all of its properties or assets to any other person under any plan
or arrangement contemplating the dissolution of the Company, then, in each such
case, as a condition to the consummation of such a transaction, proper and
adequate provision shall be made by the Company whereby the Holder, on the
exercise hereof as provided in Section 1 at any time after the consummation of
such reorganization, consolidation or merger or the effective date of such
dissolution, as the case may be, shall receive, in lieu of the Common Stock (or
Other Securities) issuable on such exercise prior to such consummation or such
effective date, the stock and other securities and property (including cash) to
which such Holder would have been entitled upon such consummation or in
connection with such dissolution, as the case may be, if such Holder had so
exercised this Warrant, immediately prior thereto, all subject to further
adjustment thereafter as provided in Sections 5 and 6.

            ii) Dissolution. Where, prior to the exercise of the Warrants, the
Company shall commence dissolution proceedings, an Exercise Period shall be
established not later than 4 weeks after the resolution to dissolve the Company
has been adopted by the board of directors of the Company, where the Holder is
entitled to exercise vested Warrants. In the event of completion of a winding-up
involving liquidation proceeds per share of Common Stock in excess of the
Exercise Price plus an annual return of 50% from the Date of Commencement per
share, all Warrants represented hereby shall vest immediately. Warrants not
exercised by the Holder in the Exercise Period shall lapse without further
notice and without any compensation.

            iii) Continuation of Terms. Upon any reorganization, consolidation,
merger or transfer (and any dissolution following any transfer) referred to in
this Section 4, this Warrant shall continue in full force and effect and the
terms hereof shall be applicable to the shares of stock and other securities and
property receivable on the exercise of this Warrant after the consummation of
such reorganization, consolidation or merger or the effective date of
dissolution following any such transfer, as the case may be, and shall be
binding upon the issuer of any such stock or other securities, including, in the
case of any such transfer, the person acquiring all or substantially all of the
properties or assets of the Company, whether or not such person shall have
expressly assumed the terms of this Warrant as provided in Section 4. In the
event this Warrant does not continue in full force and effect after the
consummation of the transactions described in this Section 4, then the Company's
securities and property (including cash, where applicable) receivable by the
Holder will be delivered to the Holder.


                                       6
<PAGE>

      e. Extraordinary Events Regarding Common Stock. In the event that the
Company shall (a) issue additional shares of the Common Stock as a dividend or
other distribution on outstanding Common Stock or any preferred stock issued by
the Company, (b) subdivide its outstanding shares of Common Stock, or (c)
combine its outstanding shares of the Common Stock into a smaller number of
shares of the Common Stock, then, in each such event, the Exercise Price shall,
simultaneously with the happening of such event, be adjusted by multiplying the
then Exercise Price by a fraction, the numerator of which shall be the number of
shares of Common Stock outstanding immediately prior to such event and the
denominator of which shall be the number of shares of Common Stock outstanding
immediately after such event, and the product so obtained shall thereafter be
the Exercise Price then in effect. The Exercise Price, as so adjusted, shall be
readjusted in the same manner upon the happening of any successive event or
events described herein in this Section 5. The number of shares of Common Stock
that the Holder shall thereafter, on the exercise hereof as provided in Section
1, be entitled to receive shall be adjusted to a number determined by
multiplying the number of shares of Common Stock that would otherwise (but for
the provisions of this Section 5) be issuable on such exercise by a fraction of
which (a) the numerator is the Exercise Price that would otherwise (but for the
provisions of this Section 5) be in effect, and (b) the denominator is the
Exercise Price in effect on the date of such exercise (taking into account the
provisions of this Section 5). In the event the Company issues additional shares
of the Common Stock or any security exercisable for or convertible into Common
Stock, where the effect of issuance is or the terms of such security provide for
the subscription for shares of Common Stock at a price per share less than the
most recent subscription price used by the Company in issuing shares of Common
Stock on market terms, proper and adequate provision shall be made by the
Company whereby the Holder, on the exercise hereof as provided in Section 1 at
any time after such issuance, shall be placed in that position the Holder would
have been if such Holder had exercised this Warrant, immediately prior thereto,
all subject to further adjustment thereafter as provided in Sections 4 and 6. In
the event the Company pays a cash dividend on the outstanding shares of Common
Stock aggregating in excess of 10% of the "net assets" of the Company (as
defined in Section 154 of the Delaware General Corporation Law), proper and
adequate provision shall be made by the Company whereby the Holder, on the
exercise hereof as provided in Section 1 at any time after such payment, shall
receive upon such exercise the number of shares of Common Stock it would
otherwise have been entitled to receive plus that number of additional shares of
Common Stock equal to the number of shares the pro rata amount of such dividend
the Holder would have received if such Holder had exercised this Warrant
immediately prior thereto would have purchased at the fair market value thereof
immediately after such dividend is paid, all subject to further adjustment
thereafter as provided in Sections 4 and 6.

      f. Certificate as to Adjustments. In each case of any adjustment or
readjustment in the shares of Common Stock (or Other Securities) issuable on the
exercise of this Warrant, the Company at its expense will promptly cause its
Chief Financial Officer or other appropriate designee to compute such adjustment
or readjustment in accordance with the terms of this Warrant and prepare a
certificate setting forth such adjustment or readjustment and showing in detail
the facts upon which such adjustment or readjustment is based, including a
statement of (a) the consideration received or receivable by the Company for any
additional shares of Common Stock (or Other Securities) issued or sold or deemed
to have been issued or sold, (b) the number of shares of Common Stock (or Other
Securities) outstanding or deemed to be outstanding, and (c) the Exercise Price
and the number of shares of Common Stock to be received upon exercise of this
Warrant, in effect immediately prior to such adjustment or readjustment and as
adjusted or readjusted as provided in this Warrant. The Company will forthwith
mail a copy of each such certificate to the Holder and any Warrant agent of the
Company (appointed pursuant to Section 10 hereof). Each such adjustment or
readjustment pursuant to the terms hereof shall seek to ensure that the
estimated financial value of the Warrant prior to the relevant event, as
estimated by the Company, shall correspond to the estimated financial value of
the Warrant following the relevant event, as estimated by the Company, subject
to confirmation by an independent appraisal at the option of the Holder.


                                       7
<PAGE>

      g. Reservation of Stock, Etc., Issuable on Exercise of Warrant; No Rights
as Stockholder. The Company will at all times reserve and keep available, solely
for issuance and delivery on the exercise of this Warrant, shares of Common
Stock (or Other Securities) from time to time issuable on the exercise of this
Warrant. Prior to the exercise of the Warrants represented hereby, the Holder of
this Warrant, as such, shall not be entitled to any right of a stockholder of
the Company, including, without limitation, the right to vote or to consent to
any action of the stockholders, to receive dividends or other distributions, to
exercise any preemptive right or to receive any notice of meeting of
stockholders and shall not be entitled to receive any notice of any proceeding
of the Company, except as provided in this Warrant.

      h. Assignment; Exchange of Warrant. Warrants shall be personal and cannot
be made the subject of pledging or assignment. However, upon the death of the
Holder, the right to exercise Warrants vested pursuant to Section 2.1 and 2.3
shall pass to the estate of the beneficiaries provided that such estate or
beneficiaries accept this Warrant.

      i. Replacement of Warrant. On receipt of evidence reasonably satisfactory
to the Company of the loss, theft, destruction or mutilation of this Warrant
and, in the case of any such loss, theft or destruction of this Warrant, on
delivery of an indemnity agreement or security reasonably satisfactory in form
and amount to the Company or, in the case of any such mutilation, on surrender
and cancellation of this Warrant, the Company at its expense will execute and
deliver, in lieu thereof, a new Warrant of like tenor.

      j. Warrant Agent. The Company may, by written notice to the each Holder of
the Warrant, appoint an agent for the purpose of issuing Common Stock (or Other
Securities) on the exercise of this Warrant pursuant to Section 1, and replacing
this Warrant pursuant to Section 9, or any of the foregoing, and thereafter any
such issuance, exchange or replacement, as the case may be, shall be made at
such office by such agent.

      k. Transfer on the Company's Books. Until this Warrant is transferred on
the books of the Company, the Company may treat the registered Holder hereof as
the absolute owner hereof for all purposes, notwithstanding any notice to the
contrary.

      l. Notices, Etc. All notices and other communications from the Company to
the Holder shall be mailed by first class registered or certified mail, postage
prepaid, at such address as may have been furnished to the Company in writing by
such Holder or, until any such Holder furnishes to the Company an address, then
to, and at the address of, the last Holder who has so furnished an address to
the Company.


                                       8
<PAGE>

      m. Miscellaneous. This Warrant and any term hereof may be changed, waived,
discharged or terminated only by an instrument in writing signed by the party
against which enforcement of such change, waiver, discharge or termination is
sought. THIS WARRANT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE
LAWS OF STATE OF NEW YORK WITHOUT REGARD TO PRINCIPLES OF CONFLICTS OF LAWS. ANY
ACTION BROUGHT CONCERNING THE TRANSACTIONS CONTEMPLATED BY THIS WARRANT SHALL BE
BROUGHT ONLY IN THE STATE COURTS OF NEW YORK OR IN THE FEDERAL COURTS LOCATED IN
THE STATE OF NEW YORK; PROVIDED, HOWEVER, THAT THE HOLDER MAY CHOOSE TO WAIVE
THIS PROVISION AND BRING AN ACTION OUTSIDE THE STATE OF NEW YORK. The
individuals executing this Warrant on behalf of the Company agree to submit to
the jurisdiction of such courts and waive trial by jury. The prevailing party
shall be entitled to recover from the other party its reasonable attorneys' fees
and costs. In the event that any provision of this Warrant is invalid or
unenforceable under any applicable statute or rule of law, then such provision
shall be deemed inoperative to the extent that it may conflict therewith and
shall be deemed modified to conform with such statute or rule of law. Any such
provision which may prove invalid or unenforceable under any law shall not
affect the validity or enforceability of any other provision of this Warrant.
The headings in this Warrant are for purposes of reference only, and shall not
limit or otherwise affect any of the terms hereof. The invalidity or
unenforceability of any provision hereof shall in no way affect the validity or
enforceability of any other provision hereof. The Company acknowledges that
legal counsel participated in the preparation of this Warrant and, therefore,
stipulates that the rule of construction that ambiguities are to be resolved
against the drafting party shall not be applied in the interpretation of this
Warrant to favor any party against the other party.

                   [BALANCE OF PAGE INTENTIONALLY LEFT BLANK;
                             SIGNATURE PAGE FOLLOWS]


                                       9
<PAGE>

      IN WITNESS WHEREOF, the Company has executed this Warrant as of the date
first written above.


                                      CASTLE & MORGAN HOLDINGS, INC.

WITNESS:
                                      By:
                                             -----------------------------------
                                      Name:
                                             -----------------------------------
                                      Title:
---------------------------------            -----------------------------------











                                       10
<PAGE>

                                    Exhibit A

                              FORM OF SUBSCRIPTION
                   (To Be Signed Only On Exercise Of Warrant)

TO:   Castle & Morgan Holdings, Inc.

      Attention: Chief Financial Officer

      The undersigned, pursuant to the provisions set forth in the attached
Warrant hereby irrevocable elects to purchase ___ shares of Common Stock covered
by such Warrant.

      The undersigned herewith makes payment of the full Exercise Price for such
shares at the price per share provided for in such Warrant, which is
$___________. Such payment takes the form of lawful money of the United States.

      The undersigned requests that the certificates for such shares be issued
in the name of, and delivered to ______________________________________________
whose address is
______________________________________________________________________________.

      The undersigned represents and warrants that all offers and sales by the
undersigned of the securities issuable upon exercise of the within Warrant shall
be made pursuant to registration of the Common Stock under the Securities Act of
1933, as amended (the "Securities Act") or pursuant to an exemption from
registration under the Securities Act.

Dated:
         ---------------------------   ----------------------------------------
                                       (Signature must conform to name of holder
                                       as specified on the face of the Warrant)

                                       Address:
                                               ---------------------------------

                                               ---------------------------------