<PAGE>
 
                                                                    EXHIBIT 4(N)

                        ______________________________



                            COMMONWEALTH ASSOCIATES

                                      AND

                                MEDCROSS, INC.

                                  __________



                        PLACEMENT AGENT'S COMMON STOCK
                               WARRANT AGREEMENT



                          DATED AS OF AUGUST 21, 1996

                        ______________________________
<PAGE>
 
     PLACEMENT AGENT'S WARRANT AGREEMENT dated as of August 21, 1996, between
COMMONWEALTH ASSOCIATES, a Delaware Limited Partnership (hereinafter referred to
variously as the "Holder" or the "Placement Agent") and MEDCROSS, INC., a
Florida corporation  (the "Company").

                             W I T N E S S E T H :

     WHEREAS, the Company proposes to issue to the Placement Agent warrants
("Warrants") to purchase up to an aggregate 250,000 shares of common stock, par
value $.007 per share, of the Company ("Common Stock"); and

     WHEREAS, the Placement Agent has agreed pursuant to the sales agency
agreement (the "Sales Agency Agreement") dated as of July 1, 1996 between the
Placement Agent and the Company, to sell on behalf of the Company in a private
offering ("the "Offering") pursuant to Regulation D under the Securities Act of
1933, as amended (the "Act") up to 240,000 shares of the Company's Class C
Convertible Cumulative Redeemable Preferred Stock, $10.00 par value per share
(the "Securities"); and

     WHEREAS, the Warrants to be issued pursuant to this Agreement will be
issued on the closing date of the Offering (the "Closing Date") by the Company
to the Placement Agent in consideration for, and as part of the compensation in
connection with the Offering;

     NOW, THEREFORE, in consideration of the premises, the agreements herein set
forth and other good and valuable consideration, the receipt and sufficiency of
which are hereby acknowledged, the parties hereto agree as follows:
<PAGE>
 
     1.      Grant. The Holder is hereby granted the right to purchase, at any
time from March 1, 1997 until 5:30 P.M., New York time, August 20, 2001 (the
"Warrant Exercise Term"), up to an aggregate 250,000 shares of the Company's
Common Stock (the "Warrant Shares") at an initial exercise price (subject to
adjustment as provided in Section 8 hereof) of $2.50 per Share, subject to the
                          -------                                             
terms and conditions of this Agreement.

     2.      Warrant Certificates. The warrant certificates (the "Warrant
Certificates") delivered and to be delivered pursuant to this Agreement shall be
in the form set forth in Exhibit A, attached hereto and made a part hereof, with
such appropriate insertions, omissions, substitutions, and other variations as
required or permitted by this Agreement.

     3.      Exercise of Warrant.

     (S)3.1  The Warrants initially are exercisable at an aggregate initial
exercise price of $2.50 per share payable by certified or official bank check in
New York Clearing House funds, subject to adjustment as provided in Section 8
hereof. Upon surrender of a Warrant Certificate with the annexed Form of
Election to Purchase duly executed, together with payment of the Purchase Price
(as hereinafter defined) for the Warrant Shares purchased at the Company's
principal offices, the registered holder of a Warrant Certificate ("Holder" or
"Holders") shall be entitled to receive a certificate or certificates for the
Warrant Shares so purchased. The purchase rights represented by each Warrant
Certificate are exercisable at the option of the Holder thereof, in whole or in
part (but not as to fractional shares of the Common Stock underlying the
Warrants). In the case of the purchase of less than all the Warrant Shares
purchasable under any Warrant Certificate, the Company shall cancel said Warrant
Certificate

                                       2
<PAGE>
 
upon the surrender thereof and shall execute and deliver a new Warrant
Certificate of like tenor for the balance of the Warrant Shares purchasable
thereunder.

     (S)3.2  Cashless Exercise.  At any time during the Warrant Exercise Term,
the Holder may, at its option, exchange the Warrants represented by such
Holder's Warrant certificate, in whole or in part (a "Warrant Exchange"), into
the number of fully paid and non-assessable Warrant Shares determined in
accordance with this Section 3.2, by surrendering such Warrant certificate at
the principal office of the company or at the office of its transfer agent,
accompanied by a notice stating such Holder's intent to effect such exchange,
the number of Warrant Shares to be exchanged and the date on which the Holder
requests that such Warrant Exchange occur (the "Notice of Exchange")  The
Warrant Exchange shall take place on the date specified in the Notice of
Exchange, or, if later, the date the Notice of Exchange is received by the
Company (the "Exchange Date").  Certificates for the Warrant Shares issuable
upon such Warrant Exchange and, if applicable, a new Warrant of like tenor
evidencing the balance of the Warrant Shares remaining subject to the Holder's
Warrant certificate, shall be issued as of the Exchange Date and delivered to
the Holder within three (3) days following the Exchange Date. In connection with
any Warrant Exchange, the Holder's Warrant certificate shall represent the right
to subscribe for and acquire (I) the number of Warrant Shares (rounded to the
next highest integer) equal to (A) the number of Warrant Shares specified by the
Holder in its Notice of Exchange (the "Total Share Number") less (B) the number
of Warrant Shares equal to the quotient obtained by dividing (i) the product of
the Total Share Number and the existing Exercise Price (as hereinafter defined)
per Share by (ii) the Market Price (as hereafter defined) of a share of Common
Stock.

                                       3
<PAGE>
 
             As used herein, the phrase "Market Price" at any date shall be
deemed to be the last reported sale price, or, in case no such reported sale
takes place on such day, the average of the last reported sale prices for the
last three trading days, in either case as officially reported by the principal
securities exchange on which the Common Stock is listed or admitted to trading
or as reported in the Nasdaq National Market System, or, if the Common Stock is
not listed or admitted to trading on any national securities exchange or quoted
on the Nasdaq National Market System, the last reported sale price as furnished
by the National Association of Securities Dealers, Inc. through Nasdaq or
similar organization if Nasdaq is no longer reporting such information, or if
the Common Stock is not quoted on Nasdaq, as determined in good faith by
resolution of the Board of Directors of the Company, based on the best
information available to it for the two days immediately preceding such issuance
or sale and the day of such issuance or sale.

     4.      Issuance of Certificates. Upon the exercise of the Warrants, the
issuance of certificates for Warrant Shares or other securities, properties or
rights underlying such Warrants, shall be made forthwith (and in any event
within three (3) business days thereafter) without charge to the Holder thereof
including, without limitation, any tax which may be payable in respect of the
issuance thereof, and such certificates shall (subject to the provisions of
Section 7 hereof) be issued in the name of, or in such names as may be directed
-------                                                                        
by, the Holder thereof; provided, however, that the Company shall not be
required to pay any tax which may be payable in respect of any transfer involved
in the issuance and delivery of any such certificates in a name other than that
of the Holder and the Company shall not be required to issue or deliver such
certificates unless or until the person or persons requesting the issuance
thereof shall have paid

                                       4
<PAGE>
 
to the Company the amount of such tax or shall have established to the
satisfaction of the Company that such tax has been paid.

     The Warrant Certificates and the certificates representing the Warrant
Shares (and/or other securities, property or rights issuable upon the exercise
of the Warrants) shall be executed on behalf of the Company by the manual or
facsimile signature of the then present Chairman or Vice Chairman of the Board
of Directors or President or Vice President of the Company under its corporate
seal reproduced thereon, attested to by the manual or facsimile signature of the
then present Secretary or Assistant Secretary of the Company. Warrant
Certificates shall be dated the date of execution by the Company upon initial
issuance, division, exchange, substitution or transfer.

     5.      Restriction on Transfer of Warrants.

             Upon exercise, in part or in whole, of the Warrants, certificates
representing the Warrant Shares, shall bear a legend substantially similar to
the legend set forth in Section 7.1.

             The Holder of a Warrant Certificate, by its acceptance thereof,
covenants and agrees that the Warrants are being acquired as an investment and
not with a view to the distribution thereof.

     6.      Exercise Price.

     (S)6.1  Initial and Adjusted Exercise Price. Except as otherwise provided
in Section 8 hereof, the initial exercise price of each Warrant shall be $2.50.
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The adjusted exercise price shall be the price which shall result from time to
time from any and all adjustments of the initial exercise price in accordance
with the provisions of Section 8 hereof.

                                       5
<PAGE>
 
     (S)6.2  Exercise Price. The term "Exercise Price" herein shall mean the
initial exercise price or the adjusted exercise price, depending upon the
context.

     7.      Registration Rights.

     (S)7.1  Registration Under the Securities Act of 1933.  The Warrants,
the Warrant Shares and any of the other securities issuable upon exercise of the
Warrants have not been registered under the Securities Act of 1933, as amended
(the "Act").  Upon exercise, in part or in whole, of the Warrants, certificates
representing the Warrant Shares and any of the other securities issuable upon
exercise of the Warrants (collectively, the "Warrant Securities") shall bear the
following legend:

     The securities represented by this certificate have not been
     registered under the Securities Act of 1933, as amended ("Act"), and
     may not be offered or sold except pursuant to (i) an effective
     registration statement under the Act, (ii) to the extent applicable,
     Rule 144 under the Act (or any similar rule under such Act relating to
     the disposition of securities), or (iii) an opinion of counsel, if
     such opinion shall be reasonably satisfactory to counsel to the
     issuer, that an exemption from registration under such Act is
     available.


     (S)7.2  Piggyback Registration. If, at any time from the date hereof
through August 20, 2003, the Company proposes to register any of its securities
under the Act (other than in connection with a merger or pursuant to Form S-8)
it will give written notice by registered mail, at least thirty (30) days prior
to the filing of each such registration statement, to each of the Placement
Agent and to all other Holders of the Warrants and/or the Warrant Securities of
its intention to do so. If any of the Placement Agent or other Holders of the
Warrants and/or Warrant Securities notify the Company within twenty (20) days
after receipt of any such notice of its or their desire to include any such
securities in such proposed registration statement, the Company shall afford
each of the Placement Agent and such Holders of the Warrants and/or Warrant
Securities the opportunity to have any such Warrants and/or

                                       6
<PAGE>
 
Warrant Securities registered under such registration statement.

     Notwithstanding the provisions of this Section 7.2, the Company shall have
the right at any time after it shall have given written notice pursuant to this
Section 7.2 (irrespective of whether a written request for inclusion of any such
securities shall have been made) to elect not to file any such proposed
registration statement, or to withdraw the same after the filing but prior to
the effective date thereof.

     (S)7.3  Demand Registration.

     (a)     At any time commencing August 20 1997, through and including August
1, 2003, the Holders of the Warrants and/or Warrant Securities representing a
"Majority" (as hereinafter defined) of such securities (assuming the exercise of
all of the Warrants) shall have the right (which right is in addition to the
registration rights under Section 7.2 hereof), exercisable by written notice to
the Company, to have the Company prepare and file with the Commission, on one
occasion, a registration statement and such other documents, including a
prospectus, as may be necessary in the opinion of both counsel for the Company
and counsel for the Placement Agent and such Holders, in order to comply with
the provisions of the Act, so as to permit a public offering and sale of their
respective Warrant Securities for nine (9) consecutive months by such Holders
and any other Holders of the Warrants and/or Warrant Securities who notify the
Company within ten (10) days after receiving notice from the Company of such
request; provided, however, that in the event the Company fails to file a
registration statement, and use its best efforts to have same declared
effective, covering the conversion shares issuable upon conversion of certain
10% Notes (the "Notes") of the Company (the "Conversion Shares") within

                                       7
<PAGE>
 
ninety-five (95) days of a request by the holders of a majority of the
Conversion Shares and/or Notes to register the Conversion Shares, then, in such
event, the commencement date of the demand registration rights granted under
this Section 7.3(a) shall be accelerated from August 20, 1997 to the day
immediately following the expiration of such 95 day period, and in such
circumstances, the period specified in Section 7.4(a) shall be reduced from 95
days to 30 days.

     (b)     The Company covenants and agrees to give written notice of any
registration request under this Section 7.3 by any Holder or Holders to all
other registered Holders of the Warrants and the Warrant Securities within ten
(10) days from the date of the receipt of any such registration request.

     (c)     Notwithstanding anything to the contrary contained herein, if the
Company shall not have complied with Section 7.4(a) hereof pursuant to the
written notice specified in Section 7.3(a) of a Majority of the Holders of the
Warrants and/or Warrant Securities, the Company agrees that upon twenty (20)
days prior written notice of election of a Majority of the Holders of the
Warrants and/or Warrant Securities, and the failure of the Company to comply
with Section 7.4(a) on or before the expiration of such 20 day period, it shall
repurchase (i) any and all Warrant Securities at the higher of the Market Price
(as defined in Section 8.1(a)) per share of Common Stock on (x) the date of the
notice sent pursuant to Section 7.3(a) or (y) the expiration of the period
specified in Section 7.4(a) and (ii) any and all Warrants at such Market Price
less the exercise prices of such Warrant. Such repurchase shall be in
immediately available funds and shall close within two (2) days after the later
of (i) the expiration of the period specified in Section 7.4(a) or (ii) the
delivery of the written notice of election specified in this Section 7.3(d).

                                       8
<PAGE>
 
     (S)7.4  Covenants of the Company With Respect to Registration. In
connection with any registration under Section 7.2 or 7.3 hereof, the Company
covenants and agrees as follows:

     (a)     The Company shall use its best efforts to file a registration
statement within ninety-five (95) days of receipt of any demand therefor, shall
use its best efforts to have any registration statements declared effective at
the earliest possible time, and shall furnish each Holder desiring to sell
Warrant Securities such number of prospectuses as shall reasonably be requested.
Best efforts shall include the reasonable efforts to insure the availability of
financial statements and other matters necessary to effectuate the filing.

     (b)     The Company shall pay all costs (excluding fees and expenses of
Holder(s) counsel and any underwriting or selling commissions), fees and
expenses in connection with all registration statements filed pursuant to
Sections 7.2 and 7.3(a) hereof including, without limitation, the Company's
legal and accounting fees, printing expenses, blue sky fees and expenses.  If
the Company shall fail to comply with the provisions of Section 7.4(a), the
Company shall, in addition to any other equitable or other relief available to
the Holder(s), be liable for any or all incidental, special and consequential
damages and damages due to loss of profit sustained by the Holder(s) requesting
registration of their Warrant Securities. Notwithstanding anything herein to the
contrary, provided the Company complies with the provisions of Section 7.3(c),
the Company shall have no liability under the foregoing sentence of this Section
7.4(b).

     (c)     The Company will take all necessary action which may be required in
qualifying or registering the Warrant Securities included in a registration
statement for offering and sale under the securities or blue sky laws of such
states as reasonably are requested by the Holder(s),

                                       9
<PAGE>
 
provided that the Company shall not be obligated to execute or file any general
consent to service of process or to qualify as a foreign corporation to do
business under the laws of any such jurisdiction.


     (d)     The Company shall indemnify the Holder(s) of the Warrant Securities
to be sold pursuant to any registration statement and each person, if any, who
controls such Holders within the meaning of Section 15 of the Act or Section
20(a) of the Securities Exchange Act of 1934, as amended ("Exchange Act"),
against all loss, claim, damage, expense or liability (including all expenses
reasonably incurred in investigating, preparing or defending against any claim
whatsoever) to which any of them may become subject under the Act, the Exchange
Act or otherwise, arising from such registration statement but only to the same
extent and with the same effect as the provisions pursuant to which the Company
has agreed to indemnify the Placement Agent contained in Section 10 of the Sales
Agency Agreement.

     (e)     The Holder(s) of the Warrant Securities to be sold pursuant to a
registration statement, and their successors and assigns, shall severally, and
not jointly, indemnify the Company, its officers and directors and each person,
if any, who controls the Company within the meaning of Section 15 of the Act or
Section 20(a) of the Exchange Act, against all loss, claim, damage or expense or
liability (including all expenses reasonably incurred in investigating,
preparing or defending against any claim whatsoever) to which they may become
subject under the Act, the Exchange Act or otherwise, arising from information
furnished by or on behalf of such Holders, or their successors or assigns, for
specific inclusion in such registration statement to the same extent and with
the same effect as the provisions contained in

                                       10
<PAGE>
 
Section 10 of the Sales Agency Agreement pursuant to which the Placement Agent
has agreed to indemnify the Company.

     (f)     Nothing contained in this Agreement shall be construed as requiring
the Holder(s) to exercise their Warrants prior to the initial filing of any
registration statement or the effectiveness thereof.

     (g)     The Company shall use its best efforts not to permit the inclusion
of any securities other than the Warrants and Warrant Securities to be included
in any registration statement filed pursuant to Section 7.3 hereof or permit any
other registration statement to be or remain effective during the effectiveness
of a registration statement filed pursuant to Section 7.3 hereof (except
                                              -------                   
registration statements on Form S-8 or filed pursuant to contractual commitments
existing on the date hereof), without the prior written consent of the Holders
of the Warrants and Warrant Securities representing a majority of such
securities.  In the event the Company is required to include securities other
than the Warrants and Warrant Securities in a registration statement filed under
Section 7.3, the Holders shall be entitled to one additional right to demand the
preparation and filing of a registration under Section 7.3

     (h)     The Company shall furnish to each broker-dealer participating as an
underwriter, if any, a signed counterpart, addressed to such Holder or
underwriter, of (i) an opinion of counsel to the Company, dated the effective
date of such registration statement (and, if such registration includes an
underwritten public offering, an opinion dated the date of the closing under the
underwriting agreement), and (ii) a "cold comfort" letter dated the effective
date of such registration statement (and, if such registration includes an
underwritten public offering, a letter dated the date of the closing under the
underwriting agreement) signed by the

                                       11
<PAGE>
 
independent public accountants who have issued a report on the Company's
financial statements included in such registration statement, in each case
covering substantially the same matters with respect to such registration
statement (and the prospectus included therein) and, in the case of such
accountants' letter, with respect to events subsequent to the date of such
financial statements, as are customarily covered in opinions of issuer's counsel
and in accountants' letters delivered to underwriters in underwritten public
offerings of securities.

     (i)     The Company as soon as practicable, but in any event not later than
45 days after the end of the 12-month period beginning on the day after the end
of the fiscal quarter of the Company during which the effective date of the
Registration Statement occurs (90 days in the event that the end of such fiscal
quarter is the end of the Company's fiscal year), shall make generally available
to its security holders, in the manner specified in Rule 158(b) of the Rules and
Regulations, and to the Placement Agent, an earnings statement which will be in
the detail required by, and will otherwise comply with, the provisions of
Section 11(a) of the Act and Rule 158(a) of the Rules and Regulations, which
statement need not be audited unless required by the Act, covering a period of
at least 12 consecutive months after the effective date of the Registration
Statement.

     (j)     The Company shall deliver promptly to each Holder participating in
the offering requesting the correspondence and memoranda described below and the
managing underwriters, if any, copies of all correspondence between the
Commission and the Company, its counsel or auditors and all memoranda relating
to discussions with the Commission or its staff with respect to the registration
statement and permit each Holder and underwriter to do such investigation, upon
reasonable advance notice, with respect to information contained in or omitted
from the

                                       12
<PAGE>
 
registration statement as it deems reasonably necessary to comply with
applicable securities laws or rules of the National Association of Securities
Dealers, Inc. ("NASD"). Such investigation shall include access to books,
records and properties and opportunities to discuss the business of the Company
with its officers and independent auditors, all to such reasonable extent and at
such reasonable times and as often as any such Holder shall reasonably request.

     (k)     The Company shall enter into an underwriting agreement with the
managing underwriters selected for such underwriting by Holders holding a
Majority of the Warrant Securities requested to be included in such
underwriting. Such agreement shall be satisfactory in form and substance to the
Company, each Holder and such managing underwriters, and shall contain such
representations, warranties and covenants by the Company and such other terms as
are customarily contained in agreements of that type used by the managing
underwriter.

     The Holders shall be parties to any underwriting agreement relating to an
underwritten sale of their Warrant Securities and may, at their option, require
that any or all the representations, warranties and covenants of the Company to
or for the benefit of such underwriters shall also be made to and for the
benefit of such Holders. Such Holders shall not be required to make any
representations or warranties to or agreements with the Company or the
underwriters except as they may relate to such Holders and their intended
methods of distribution.

     (1)     For purposes of this Agreement, the term "Majority" in reference to
the Holders of Warrants or Warrant Securities, shall mean in excess of fifty
percent (50%) of the then outstanding Warrants or Warrant Securities that (i)
are not held by the Company, an affiliate, officer, creditor, employee or agent
thereof or any of the ir respective affiliates, members of their

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<PAGE>
 
family, persons acting as nominees or in conjunction therewith or (ii) have not
been resold to the public pursuant to a registration statement filed with the
Commission under the Act.

     8.      Adjustments to Exercise Price and Number of Securities.

     (S)8.1  (a) Computation of Adjusted Exercise Price. Except as hereinafter
provided, in case the Company shall at any time after the date hereof issue or
sell any shares of Common Stock (other than the issuances or sales referred to
in Section 8.7 hereof), including shares held in the Company's treasury and
shares of Common Stock issued upon the exercise of any options, rights or
warrants, to subscribe for shares of Common Stock and shares of Common Stock
issued upon the direct or indirect conversion or exchange of securities for
shares of Common Stock, for a consideration per share less than the Exercise
Price in effect immediately prior to the issuance or sale of such shares or the
"Market Price" (as defined in Section 8. l(vi) hereof) per share of Common Stock
on the date immediately prior to the issuance or sale of such shares or without
consideration, then forthwith upon such issuance or sale, the Exercise Price
shall (until another such issuance or sale) be reduced to the price (calculated
to the nearest full cent) equal to the quotient derived by dividing (A) an
amount equal to the sum of (X) the product of (a) the lower of (i) the Exercise
Price in effect immediately prior to such issuance or sale and (ii) the Market
Price per share of Common Stock on the date immediately prior to the issuance or
sale of such shares, in either event, reduced, but not below the par value of
the Common Stock, by the positive difference between the (u) "Market Price" per
share of Common Stock on the date immediately prior to the issuance or sale and
(v) the amount per share received in connection with such issuance or sale,
multiplied by (b) the total number of shares of Common Stock outstanding
immediately prior to such issuance or sale plus, (Y) the aggregate of the

                                       14
<PAGE>
 
amount of all consideration, if any, received by the Company upon such issuance
or sale, by (B) the total number of shares of Common Stock outstanding
immediately after such issuance or sale; provided, however, that in no event
shall the Exercise Price be adjusted pursuant to this computation to an amount
in excess of the Exercise Price in effect immediately prior to such computation,
except in the case of a combination of outstanding shares of Common Stock, as
provided by Section 8.3 hereof.

          (b)  In addition to the foregoing, in the event the closing bid price
of the Company's Common Stock is less than $2.50  at any time during the period
commencing on the first anniversary of the Final Closing of the Offering and
ending 18 months thereafter  (the "Adjustment Period") the exercise price shall
be adjusted as herein provided.  In the event the closing bid price of the
Common Stock is less than $2.50 for five consecutive trading days during the
Adjustment Period, the Exercise Price shall be reduced to the lower of the then
current Exercise Price or the lowest of the average closing bid price of the
Common Stock for five consecutive trading days during the Adjustment Period.  In
no event shall the Conversion Price be adjusted below $1.25 on account of this
adjustment in this subparagraph 8(b).

          (c)  For the purposes of this Section 8 the term Exercise Price shall
mean the Exercise Price per share of Common Stock set forth in Section 6 hereof,
as adjusted from time to time pursuant to the provisions of this Section 8.

     For the purposes of any computation to be made in accordance with this
Section 8.1, the following provisions shall be applicable:
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     (i)  In case of the issuance or sale of shares of Common Stock for a
consideration part or all of which shall be cash, the amount of the cash
consideration therefor shall be deemed to

                                       15
<PAGE>
 
be the amount of cash received by the Company for such shares (or, if shares of
Common Stock are offered by the Company for subscription, the subscription
price, or, if either of such securities shall be sold to underwriters or dealers
for public offering without a subscription offering, the initial public offering
price) before deducting therefrom any compensation paid or discount allowed in
the sale, underwriting or purchase thereof by underwriters or dealers or others
performing similar services, or any expenses incurred in connection therewith.

     (ii)      In case of the issuance or sale (otherwise than as a dividend or
other distribution on any stock of the Company) of shares of Common Stock for a
consideration part or all of which shall be other than cash, the amount of the
consideration therefor other than cash shall be deemed to be the value of such
consideration as determined in good faith by the Board of Directors of the
Company.

     (iii)     Shares of Common Stock issuable by way of dividend or other
distribution on any stock of the Company shall be deemed to have been issued
immediately after the opening of business on the day following the record date
for the determination of stockholders entitled to receive such dividend or other
distribution and shall be deemed to have been issued without consideration.

     (iv)      The reclassification of securities of the Company other than
shares of Common Stock into securities including shares of Common Stock shall be
deemed to involve the issuance of such shares of Common Stock for a
consideration other than cash immediately prior to the close of business on the
date fixed for the determination of security holders entitled to receive such
shares, and the value of the consideration allocable to such shares of Common
Stock shall be determined as provided in subsection (ii) of this Section 8.1.

                                       16
<PAGE>
 
     (v)       The number of shares of Common Stock at any one time outstanding
shall include the aggregate number of shares issued or issuable (subject to
readjustment upon the actual issuance thereof) upon the exercise of options,
rights, warrants and upon the conversion or exchange of convertible or
exchangeable securities.

     (vi)      As used herein, the phrase "Market Price" at any date shall be
deemed to be the last reported sale price, or, in case no such reported sale
takes place on such day, the average of the last reported sale prices for the
last three (3) trading days, in either case as officially reported by the
principal securities exchange on which the Common Stock is listed or admitted to
trading or by the Nasdaq Stock Market, National Market ("Nasdaq"), or, if the
Common Stock is not listed or admitted to trading on any national securities
exchange or quoted by Nasdaq, the average closing bid price as furnished by the
NASD through Nasdaq or similar organization if Nasdaq is no longer reporting
such information, or if the Common Stock is not quoted on Nasdaq, as determined
in good faith by resolution of the Board of Directors of the Company, based on
the best information available to it.

     (S)8.2    Options. Rights Warrants and Convertible and Exchangeable
Securities. In case the Company shall at any time after the date hereof issue
options, rights or warrants to subscribe for shares of Common Stock, or issue
any securities convertible into or exchangeable for shares of Common Stock, for
a consideration per share less than the Exercise Price in effect or the Market
Price immediately prior to the issuance of such options, rights or warrants, or
such convertible or exchangeable securities, or without consideration, the
Purchase Price in effect immediately prior to the issuance of such options,
rights or warrants, or such convertible or 

                                       17
<PAGE>
 
exchangeable securities, as the case may be, shall be reduced to a price
determined by making a computation in accordance with the provisions of Section
8.1 hereof, provided that:

          (a)  The aggregate maximum number of shares of Common Stock, as the
     case may be, issuable under such options, rights or warrants shall be
     deemed to be issued and outstanding at the time such options, rights or
     warrants were issued, and for a consideration equal to the minimum purchase
     price per share provided for in such options, rights or warrants at the
     time of issuance, plus the consideration (determined in the same manner as
     consideration received on the issue or sale of shares in accordance with
     the terms of the Warrants), if any, received by the Company for such
     options, rights or warrants.

          (b)  The aggregate maximum number of shares of Common Stock issuable
     upon conversion or exchange of any convertible or exchangeable securities
     shall be deemed to be issued and outstanding at the time of issuance of
     such securities, and-for a consideration equal to the consideration
     (determined in the same manner as consideration received on the issue or
     sale of shares of Common Stock in accordance with the terms of the
     Warrants) received by the Company for such securities, plus the minimum
     consideration, if any, receivable by the Company upon the conversion or
     exchange thereof.

          (c)  If any change shall occur in the price per share provided for in
     any of the options rights or warrants referred to in subsection (a) of this
     Section 8.2, or in the price per share at which the securities referred to
     in subsection (b) of this Section 8.2 are convertible or exchangeable, such
     options, rights or warrants or conversion or exchange 

                                       18
<PAGE>
 
     rights, as the case may be, shall be deemed to have expired or terminated
     on the date when such price change became effective in respect of shares
     not theretofore issued pursuant to the exercise or conversion or exchange
     thereof, and the Company shall be deemed to have issued upon such date new
     options, rights or warrants or convertible or exchangeable securities at
     the new price in respect of the number of shares issuable upon the exercise
     of such options, rights or warrants or the conversion or exchange of such
     convertible or exchangeable securities.

          (d)  Notwithstanding the foregoing, the Exercise Price shall not be
     adjusted to a price less than $2.00 per share [as adjusted from time to
     time in accordance with paragraph 8.3] (the "Base Price") on account of
     this paragraph 8.2 unless the "consideration per share" referred to above
     for any such issuance or sale is less than the Base Price.

     (S)8.3    Subdivision and Combination. In case the Company shall at any
time subdivide or combine the outstanding shares of Common Stock, the Exercise
Price shall forthwith be proportionately decreased in the case of subdivision or
increased in the-case of combination.

     (S)8.4    Adjustment in Number of Securities. Upon each adjustment of the
Exercise Price pursuant to the provisions of this Section 8, the number of
Warrant Securities issuable upon the exercise of each Warrant shall be adjusted
to the nearest full amount by multiplying a number equal to the Exercise Price
in effect immediately prior to such adjustment by the number of Warrant
Securities issuable upon exercise of the Warrants immediately prior to such
adjustment and dividing the product so obtained by the adjusted Exercise Price.

                                       19
<PAGE>
 
     (S)8.5    Definition of Common Stock. For the purpose of this Agreement,
the term "Common Stock" shall mean (i) the class of stock designated as Common
Stock in the Certificate of Incorporation of the Company as may be amended as of
the date hereof, or (ii) any other class of stock resulting from successive
changes or reclassifications of such Common Stock, consisting solely of changes
in par value, or from par value to no par value, or from no par value to par
value. In the event that the Company shall after the date hereof issue
securities with greater or superior voting rights than the shares of Common
Stock outstanding as of the date hereof, the Holder, at its option, may receive
upon exercise of any Warrant either shares of Common Stock or a like number of
such securities with greater or superior voting rights.

     (S)8.6    Merger or Consolidation. In case of any consolidation of the
Company with, or merger of the Company with, or merger of the Company into,
another corporation (other than a consolidation or merger which does not result
in any reclassification or change of the outstanding Common Stock), the
corporation formed by such consolidation or merger shall execute and deliver to
the Holder a supplemental warrant agreement providing that the holder of each
Warrant then outstanding or to be outstanding shall have the right thereafter
(until the expiration of such Warrant) to receive, upon exercise of such
warrant, the kind and amount of shares of stock and other securities and
property receivable upon such consolidation or merger, by a holder of the number
of shares of Common Stock of the Company for which such warrant might have been
exercised immediately prior to such consolidation, merger, sale or transfer.
Such supplemental warrant agreement shall provide for adjustments which shall be
identical to the adjustments provided in Section 8. The above provision of this
subsection shall similarly apply to successive consolidations or mergers.

                                       20
<PAGE>
 
     (S)8.7    No Adjustment of Exercise Price in Certain Cases.  No adjustment
of the Exercise Price shall be made:

          (a)  Upon the issuance or sale of the Securities sold in the Offering
     or the shares of Common Stock issuable upon the conversion or exercise of
     any Securities sold in the Offering,  or the conversion or exercise of
     securities outstanding on the date hereof, or contemplated to be issued by
     the memorandum of the Offering including the Dividend Shares as defined
     therein; or

          (b)  If the amount of said adjustment shall be less than two cents
     ($.02) per Warrant, provided, however, that in such case any adjustment
     that would otherwise be required then to be made shall be carried forward
     and shall be made at the time of and together with the next subsequent
     adjustment which, together with any adjustment so carried forward, shall
     amount to at least two cents ($.02) per Warrant.

     (S)8.9    Dividends and Other Distributions. In the event that the Company
shall at any time prior to the exercise of all Warrants declare a dividend
(other than a dividend consisting solely of shares of Common Stock) or otherwise
distribute to its stockholders any assets, property, rights, evidences of
indebtedness, securities (other than shares of Common Stock), whether issued by
the Company or by another, or any other thing of value, the Holders of the
unexercised Warrants shall thereafter be entitled, in addition to the shares of
Common Stock or other securities and property receivable upon the exercise
thereof, to receive, upon the exercise of such Warrants, the same property,
assets, rights, evidences of indebtedness, securities or any other thing of
value that they would have been entitled to receive at the time of such dividend
or distribution as if the Warrants had been exercised immediately prior to such
dividend or 

                                       21
<PAGE>
 
distribution. At the time of any such dividend or distribution, the Company
shall make appropriate reserves to ensure the timely performance of the
provisions of this subsection 8.9.

     9.   Exchange and Replacement of Warrant Certificates. Each Warrant
Certificate is exchangeable without expense, upon the surrender thereof by the
registered Holder at the principal executive office of the Company, for a new
Warrant Certificate of like tenor and date representing in the aggregate the
right to purchase the same number of Warrant Securities in such denominations as
shall be designated by the Holder thereof at the time of such surrender.

     Upon receipt by the Company of evidence reasonably satisfactory to it of
the loss, theft, destruction or mutilation of any Warrant Certificate, and, in
case of loss, theft or destruction, of indemnity or security reasonably
satisfactory to it, and reimbursement to the Company of all reasonable expenses
incidental thereto, and upon surrender and cancellation of the Warrants, if
mutilated, the Company will make and deliver a new Warrant Certificate of like
tenor, in lieu thereof.

     10.  Elimination of Fractional Interests.  The Company shall not be
required to issue certificates representing fractions of shares of Common Stock
upon the exercise of the Warrants, nor shall it be required to issue scrip or
pay cash in lieu of fractional interests, it being the intent of the parties
that all fractional interests shall be eliminated by rounding any fraction up to
the nearest whole number of shares of Common Stock or other securities,
properties or rights.

     11.  Reservation and Listing of Securities. The Company shall at all times
reserve and keep available out of its authorized shares of Common Stock, solely
for the purpose of issuance upon the exercise of the Warrants, such number of
shares of Common Stock or other securities, properties or rights as shall be
issuable upon the exercise thereof. The Company covenants and 

                                       22
<PAGE>
 
agrees that, upon exercise of the Warrants and payment of the Exercise Price
therefor, all shares of Common Stock and other securities issuable upon such
exercise shall be duly and validly issued, fully paid, non-assessable and not
subject to the preemptive rights of any stockholder. As long as the Warrants
shall be outstanding, the Company shall use its best efforts to cause all shares
of Common Stock issuable upon the exercise of the Warrants to be listed (subject
to official notice of issuance) on all securities exchanges on which the Common
Stock may then be listed and/or quoted.

     12.  Notices to Warrant Holders. Nothing contained in this Agreement shall
be construed as conferring upon the Holders the right to vote or to consent or
to receive notice as a stockholder in respect of any meetings of stockholders
for the election of directors or any other matter, or as having any rights
whatsoever as a stockholder of the Company. If, however, at any time prior to
the expiration of the Warrants and their exercise, any of the following events
shall occur:
          (a)  the Company shall take a record of the holders of its shares of
     Common Stock for the purpose of entitling them to receive a dividend or
     distribution payable otherwise than in cash, or a cash dividend or
     distribution payable otherwise than out of current or retained earnings, as
     indicated by the accounting treatment of such dividend or distribution on
     the books of the Company; or

          (b)  the Company shall offer to all the holders of its Common Stock
     any additional shares of capital stock of the Company or securities
     convertible into or exchangeable for shares of capital stock of the
     Company, or any option, right or warrant to subscribe therefor; or

                                       23
<PAGE>
 
          (c)  a dissolution, liquidation or winding up of the Company (other
     than in connection with a consolidation or merger) or a sale of all or
     substantially all of its property assets and business as an entirety shall
     be proposed; then, in any one or more of said events the Company shall give
     written notice of such event at least fifteen (15) days prior to the date
     fixed as a record date or the date of closing the transfer books for the
     determination of the stockholders entitled to such dividend, distribution,
     convertible or exchangeable securities or subscription rights, or entitled
     to vote on such proposed dissolution, liquidation, winding up or sale.
     Such notice shall specify such record date or the date of closing the
     transfer books, as the case may be. Failure to give such notice or any
     defect therein shall not affect the validity of any action taken in
     connection with the declaration or payment of any such dividend, or the
     issuance of any convertible or exchangeable securities, or subscription
     rights, options or warrants, or any proposed dissolution, liquidation,
     winding up or sale.

     13.  Notices.

     All notices requests, consents and other communications hereunder shall be
in writing and shall be deemed to have been duly made when delivered, or mailed
by registered or certified mail, return receipt requested:

          (a)  If to the registered Holder of the Warrants, to the address of
     such Holder as shown on the books of the Company; or

          (b)  If to the Company, to the address set forth in Section 3 hereof
     or to such other address as the Company may designate by notice to the
     Holders.

                                       24
<PAGE>
 
     14.  Supplements and Amendments. The Company and the Placement Agent may
from time to time supplement or amend this Agreement without the approval of any
holders of Warrant Certificates (other than the Placement Agent) in order to
cure any ambiguity, to correct or supplement any provision contained herein
which may be defective or inconsistent with any provisions herein or to make any
other provisions in regard to matters or questions arising hereunder which the
Company and the Placement Agent may deem necessary or desirable and which the
Company and the Placement Agent deem shall not adversely affect the interests of
the Holders of Warrant Certificates.

     15.  Successors. All the covenants and provisions of this Agreement shall
be binding upon and inure to the benefit of the Company, the Holders and their
respective successors and assigns hereunder.

     16.  Termination. This Agreement shall terminate at the close of business
on August 30, 2005. Notwithstanding the foregoing, the indemnification
provisions of Section 7 shall survive such termination until the close of
business on August 30, 2005.

     17.  Governing Law: Submission to Jurisdiction. This Agreement and each
Warrant Certificate issued hereunder shall be deemed to be a contract made under
the laws of the State of New York and for all purposes shall be construed in
accordance with the laws of said State without giving effect to the rules of
said State governing the conflicts of laws.

     The Company, the Placement Agent and the Holders hereby agree that any
action, proceeding or claim against it arising out of, or relating in any way
to, this Agreement shall be brought and enforced in the courts of the State of
New York or of the United States of America for the Southern District of New
York, and irrevocably submits to such jurisdiction, which 

                                       25
<PAGE>
 
jurisdiction shall be exclusive. The Company, the Placement Agent and the
Holders hereby irrevocably waive any objection to such exclusive jurisdiction or
inconvenient forum. Any such process or summons to be served upon any of the
Company, the Placement Agent and the Holders (at the option of the party
bringing such action, proceeding or claim) may be served by transmitting a copy
thereof, by registered or certified mail, return receipt requested, postage
prepaid, addressed to it at the address set forth in Section 13 hereof. Such
mailing shall be deemed personal service and shall be legal and binding upon the
party so served in any action, proceeding or claim. The Company, the Placement
Agent and the Holders agree that the prevailing party(ies) in any such action or
proceeding shall be entitled to recover from the other party(ies) all of
its/their reasonable legal costs and expenses relating to such action or
proceeding and/or incurred in connection with the preparation therefor.

     18.  Entire Agreement: Modification. This Agreement (including the Sales
Agency Agreement to the extent portions thereof are referred to herein) contains
the entire understanding between the parties hereto with respect to the subject
matter hereof and may not be modified or amended except by a writing duly signed
by the party against whom enforcement of the modification or amendment is
sought.

     19.  Severability. If any provision of this Agreement shall be held to be
invalid or unenforceable, such invalidity or unenforceability shall not affect
any other provision of this Agreement.

     20.  Captions. The caption headings of the Sections of this Agreement are
for convenience of reference only and are not intended, nor should they be
construed as, a part of this Agreement and shall be given no substantive effect.

                                       26
<PAGE>
 
     21.  Benefits of this Agreement. Nothing in this Agreement shall be
construed to give to any person or corporation other than the Company and the
Placement Agent and any other registered Holder(s) of the Warrant Certificates
or Warrant Securities any legal or equitable right, remedy or claim under this
Agreement; and this Agreement shall be for the sole and exclusive benefit of the
Company and the Placement Agent and any other Holder(s) of the Warrant
Certificates or Warrant Securities.

     22.  Counterparts. This Agreement may be executed in any number of
counterparts and each of such counterparts shall for all purposes be deemed to
be an original, and such counterparts shall together constitute but one and the
same instrument.

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed, as of the day and year first above written.

Attest:                                       MEDCROSS, INC.


____________________________                  By: ______________________________
Secretary                                         Name:
                                                  Title:


[SEAL]                                        COMMONWEALTH ASSOCIATES


                                              By: ______________________________
                                                  Name:
                                                  Title:

                                       27
<PAGE>
 
THE WARRANTS REPRESENTED BY THIS CERTIFICATE AND THE OTHER SECURITIES ISSUABLE
UPON EXERCISE THEREOF MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO (i) AN
EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933, (ii) TO THE
EXTENT APPLICABLE, RULE 144 UNDER SUCH ACT (OR ANY SIMILAR RULE UNDER SUCH ACT
RELATING TO THE DISPOSITION OF SECURITIES), OR (iii) AN OPINION OF COUNSEL, IF
SUCH OPINION SHALL BE REASONABLY SATISFACTORY TO COUNSEL FOR THE ISSUER, THAT AN
EXEMPTION FROM REGISTRATION UNDER SUCH ACT IS AVAILABLE.

                            EXERCISABLE ON OR BEFORE
                   5:30 P.M., NEW YORK TIME, August 21, 2001

No. W-C2                                                        250,000 Warrants

                              WARRANT CERTIFICATE

     This Warrant Certificate certifies that Commonwealth Associates, or
registered assigns, is the registered holder of 250,000 Warrants to purchase
initially, at any time from March 1, 1997 until 5:30 p.m. New York time on
August 20, 2001 ("Expiration Date"), up to 250,000 fully-paid and non-assessable
shares of common stock, par value $.007 per share ("Common Stock") of Medcross,
Inc., a Delaware corporation (the "Company"), at the initial exercise price,
subject to adjustment in certain events (the "Exercise Price"), of $2.50 per
share of Common Stock upon surrender of this Warrant Certificate and payment of
the Exercise Price at an office or agency of the Company, but subject to the
conditions set forth herein and in the warrant agreement dated as of August 21,
1996 between the Company and COMMONWEALTH ASSOCIATES, (the "Warrant Agreement").
Payment of the Exercise Price shall be made by certified or official bank check
in New York Clearing House funds payable to the order of the Company.

     No Warrant may be exercised after 5:30 p.m., New York time, on the
Expiration Date, at which time all Placement Agent's Warrants evidenced hereby,
unless exercised prior thereto, hereby shall thereafter be void.

     The Warrants evidenced by this Warrant Certificate are part of a duly
authorized issue of Warrants pursuant to the Placement Agent's Warrant
Agreement, which Warrant Agreement is hereby incorporated by reference in and
made a part of this instrument and is hereby referred to for a description of
the rights, limitation of rights, obligations, duties and immunities thereunder
of the Company and the holders (the words "holders" or "holder" meaning the
registered holders or registered holder) of the Warrants.

     The Placement Agent's Warrant Agreement provides that upon the occurrence
of certain events the Exercise Price and/or number of the Company's securities
issuable thereupon may, subject to certain conditions, be adjusted. In such
event, the Company will, at the request of the holder, issue a new Warrant
Certificate evidencing the adjustment in the Exercise Price and the 

                                       1
<PAGE>
 
number and/or type of securities issuable upon the exercise of the Warrants;
provided, however, that the failure of the Company to issue such new Warrant
Certificates shall not in any way change, alter or otherwise impair, the rights
of the holder as set forth in the Placement Agent's Warrant Agreement.

     Upon due presentment for registration of transfer of this Warrant
Certificate at an office or agency of the Company, a new Warrant Certificate or
Warrant Certificates of like tenor and evidencing in the aggregate a like number
of Warrants shall be issued to the transferee(s) in exchange for this Warrant
Certificate, subject to the limitations provided herein and in the Placement
Agent's Warrant Agreement, without any charge except for any tax or other
governmental charge imposed in connection with such transfer.

     Upon the exercise of less than all of the Warrants evidenced by this
Certificate, the Company shall forthwith issue to the holder hereof a new
Warrant Certificate representing such numbered unexercised Warrants.

     The Company may deem and treat the registered holder(s) hereof as the
absolute owner(s) of this Warrant Certificate (notwithstanding any notation of
ownership or other writing hereon made by anyone), for the purpose of any
exercise hereof, and of any distribution to the holder(s) hereof, and for all
other purposes, and the Company shall not be affected by any notice to the
contrary.
 
     All terms used in this Warrant Certificate which are defined in the
Placement Agent's Warrant Agreement shall have the meanings
assigned to them in the Placement Agent's Warrant Agreement.

     IN WITNESS WHEREOF, the Company has caused this Warrant Certificate to be
duly executed under its corporate seal.

Dated as of August 21, 1996

                                              MEDCROSS, INC.

Attest:
                                              By___________________________
                                                Name:
                                                Title:
--------------------------
Secretary

                                       2

[SEAL]
<PAGE>
 
                        [FORM OF ELECTION TO PURCHASE]



     The undersigned hereby irrevocably elects to exercise the right,
represented by this Warrant Certificate, to purchase __________ shares of Common
Stock and herewith tenders in payment for such securities a certified or
official bank check payable in New York Clearing House Funds to the order of
Medcross Inc. in the amount of $____________, all in accordance with the terms
hereof.  The undersigned requests that a certificate for such securities be
registered in the name of _________________________ whose address is
_____________________________________________ and that such Certificate be
delivered to ___________________________ whose address is
_____________________________________________.

Dated:

                                     Signature _____________________
                                     (Signature must conform in all respects to
                                     name of holder as specified on the face of
                                     the Warrant Certificate.)



                                     _______________________________
                                     Insert Social Security or Other
                                     Identifying Number of Holder

                                       3
<PAGE>
 
                                ASSIGNMENT FORM
                                ---------------

The Holder hereby assigns and transfers unto

Name ______________________________________________________________
     (Please typewrite or print in block letters)

Address ___________________________________________________________
        ___________________________________________________________


the right to purchase Common Stock of _____________ represented by this Warrant
to the extent of _______________ shares of Common Stock as to which such right
is exercisable and does hereby irrevocably constitute and appoint
________________________________ Attorney, to transfer the same on the books of
_____________ with full power of substitution in the premises.


Date: ___________________, 199_


                                    ______________________________
                                    Name of Registered Holder



                                    ______________________________
                                    Signature



                                    ______________________________
                                    Signature, if held jointly

                                       4