LEASE AGREEMENT     

     
     LEASE AGREEMENT made this 9th day of September, 1998, by and
between 185 Commerce Drive Associates, L.P., a Pennsylvania limited partnership
("Lessor"), and Biosonics, Inc. whose primary business address is 260 New York
Drive, Fort Washington, Pa. ("Lessee").


     BACKGROUND:

          Lessor is the owner of the building located at 185 Commerce Drive,
Fort Washington, Pa. (the "Building").  Lessee desires to rent from Lessor
4,508 sq.
ft. of the Building (the "Premises"),  as outlined in the diagram attached as 
Exhibit "A".  Lessor desires to lease the Premises to Lessee and Lessee desires
to lease the Premises from Lessor (the "Lease") under the terms and conditions
set forth hereinafter.

          NOW, THEREFORE, in consideration of the foregoing Background and
the mutual covenants, conditions and agreements  herein contained, the parties
hereto, each intending to be legally bound hereby, agree as follows:


          1.   Lease Term .   Lessor hereby rents the Premises to Lessee
and Lessee hereby rents the Premises from Lessor for a term of five (5) years.
 
          2.   Minimum Rent.  The minimum rental to be paid by Lessee to
Lessor in monthly installments, in advance, on the first day of each month 
during the term of this Lease, is detailed on Exhibit B (the "Rental Schedule")
attached hereto.  The first month minimum rent shall be paid upon execution of
this Lease.

          3.   Use.      Lessee shall use and occupy the Premises as office 
space, lab and storage areas and for no other purpose.

          4.   Construction of Premises.       Lessor shall, without cost to
Lessee, do that portion of the construction and other items of work in the 
Premises ("Landlord's Work") designated in Exhibit "C" which is attached hereto
and made a part hereof.    The Landlord's Work shall be completed in a good and
workmanlike manner, in accordance with all applicable ordinances and 
regulations.
     
          5.   Commencement.  The term of this Lease, and Lessee's
obligation to pay rent hereunder shall commence on November 1, 1998 and shall
end on October 31, 2003.                     
          6.   Additional  Rent.

               (a)  Damages for Default.     Lessee agrees to pay as rent in
addition to the minimum rental herein reserved, any and all sums which may
become due by reason of the failure of Lessee to comply with all the covenants
of this Lease, and pay any and all damages, costs and expenses which the Lessor
may suffer or incur by reason of any default of the Lessee or failure on its 
part to comply with the covenants of this Lease, and each of them, and also any
and all damages of the Premises caused by any act or neglect of Lessee, less any
insurance proceeds payable to Landlord as a result thereof.
               (b)  Utilities.     Lessee further agrees to pay, as additional
rent Lessee's Share (this is 10.7% determined by dividing the total square
feet of
this Lease, 4,508, by the total square feet of the Building, 42,000) of all 
utility charges, including but not limited to gas and electric applicable to the
Premises, immediately when the same become due.  
               (c)  Water Rent.     Lessee further agrees to pay as additional
rent Lessee's Share of charges for water consumed upon the Premises. 
               (d)  Sewer Rent.     Lessee further agrees to pay as 
additional rent Lessee's Share of all sewer rental or charges for use of
sewers, 
sewage system, and sewage treatment works servicing the Premises, within thirty
(30) days after receipt of a bill from Lessor..
               (e)  Common Area Maintenance. Lessee shall pay to
Lessor Lessee's Share of the Operation and Maintenance Costs (as hereinafter
defined), in excess of the Base Cost as defined below:
               1.   The first payment of Lessee's Share of the Operation and
Maintenance Cost shall not be due or payable until January 1, 2000.  Beginning
January 1, 2000 and each month thereafter, Lessee shall pay Lessee's Share of 
the increase over the Base Cost estimated by Lessor for the year, pro-rated
equally over a 12 month period.  After Lessor calculates the actual cost, in 
the event that the amount paid by Lessee was less than the actual cost, Lessor
shall bill Lessee, and such amount shall be due within 15 days; in the event 
that Lessee paid in excess of the actual cost of Lessor, then the excess shall 
be applied toward the obligation of Lessee for the next calendar year.
     Lessor's bill shall contain a statement setting forth Lessee's actual 
Operation and Maintenance Costs for the  prior year, and if the Lease term has 
by then expired, any amount owed Lessee shall be paid to Lessee at the time such
statement is delivered to Lessee.  Such statement shall be delivered to Lessee 
by April 15th of the year following the year in question.  
               2.   The costs and expense of the operation and maintenance
of the Building (the "Operation and Maintenance Costs") shall include, without
limitation, the reasonable and necessary cost and expense to Lessor for the
following items:
                         (a)  All wages, salaries and fees of all employees
and agents engaged in the management, operation, repair, replacement,
maintenance and security of the Building, including taxes, insurance, 
administration fees and all other employee benefits relating thereto, in 
proportion to the time devoted thereto by such employees and agents;
                         (b)  All supplies and materials used in the
management, operation, repair, replacement, maintenance and security of the
Building; 
                         (c)  All "Utility Costs", including without
limitation, gas, water, sewer, electricity, power, heating, lighting, air-
conditioning and ventilation consumed by the common areas of the Building and 
the servicing thereof; 
                         (d)  All maintenance and service contracts for
the operation, repair, replacement, maintenance and security of the Building,
including, without limitation, window cleaning, and maintenance and servicing of
the security system, heating, ventilating and air-conditioning system, fire 
sprinkler system, elevators and grounds of the Building;
                         (e)  All fire (with all risk coverage) and other
casualty and public liability insurance for the Building and Lessor's personal
property and fixtures used in connection therewith; 
                         (f)  All "Real Estate Taxes" which, for the
purpose of this Article, shall mean all gross real property taxes without 
discounts and personal property taxes, charges and assessments which are levied,
assessed upon or imposed by any governmental authority during any calendar year
of the term hereof with respect to the Building and any improvements, fixtures 
and equipment and all other property of Lessor, real or personal, located in the
Building and used in connection with the operation of the Building and any tax 
which shall be levied or assessed in addition to or in lieu of such real 
property or personal property taxes, together with the reasonable costs and 
expenses (including reasonable attorney's fees, expenses and court costs) of 
contesting by appropriate proceedings the amount of validity of any of the 
aforementioned taxes or assessments; 
                         (g)  All repairs and general maintenance of the
Building;
                         (h)  All janitorial services for the Building;
                         (i)  Depreciation on exterior window blinds and
carpeting in public corridors and common areas provided by Lessor over the 
useful life thereof on a straight line basis as determined under GAAP.
                         (j)  The costs of any capital improvements made
for the purpose of reducing operating expenses (as would be determined in the
reasonable judgment of a landlord of a first class office building), or which
may be
required by governmental authority under any governmental law or regulation that
was not applicable to the Building as of the date of this Lease, which costs
shall be
amortized over the useful life thereof on a straight line basis as determined 
under GAAP, together with interest on the unamortized balance at the rate equal
to the Prime Rate established by Mellon Bank (East) National Association Bank,
Philadelphia, Pennsylvania or such higher rate as may have been paid by Lessor 
on funds borrowed for the purpose of construction of such capital improvement;
                         (k)  All other costs and expenses necessarily and
reasonably incurred by Lessor in the proper operation and maintenance of a first
class office building; provided, however, that the following shall be excluded 
from the term "Operation and Maintenance Costs": (i) expenses for any capital
improvement made to the Building, except as provided above (including but not
limited  to the resurfacing of the parking areas and driveways servicing the
Building); (ii) expenses for repairs or other work occasioned by fire,
windstorm or
other insured casualty; (iii) expenses incurred in leasing or procuring new 
tenants (e.g. for lease commissions, advertising expenses and expenses of 
renovating space for new tenants); (iv) legal expenses in enforcing the terms of
any lease; (v) interest or amortization payments on any mortgage or mortgages; 
(vi)  expenditures for which Lessor is reimbursed from any insurance carrier, 
from any tenant, including the Lessee, or from any other source; (vii)   costs 
incurred in performing work or furnishing services of a capital nature for any 
tenant; (viii)  depreciation, except as provided above; (ix)  bad debt loss, 
rent loss or reserves for either of them; (x) taxes, except as provided above; 
(xi)  if Lessee pays separately for its own utility, then the cost of all 
utilities furnished to all tenants, provided that common area utilities shall be
included in the Operation and Maintenance Costs; (xii) costs incurred in 
connection with the construction of the Building or its initial development; 
(xiii)  costs for sculpture, decorations paintings or other objects of art
in excess amounts typically spent for such items in office buildings of 
comparable quality in the competitive area  of the Building; (xiv)  costs, 
expenses or expenditures relating to the duties, liabilities or obligations of 
other tenants in the Building; (xv)  costs incurred by Lessor arising out its of
failure to perform or its breach of any of its covenants, agreements, represen-
tations, warranties, guarantees or indemnities made under this Lease or any 
other lease in the Building; (xvi)  costs of compliance, except as provided 
above fines or penalties incurred by Lessor due to violations of or noncom-
pliance with any applicable legal requirements; (xvii)  costs incurred in the 
removal, abatement or other treatment of underground storage tanks or hazardous 
substances or wastes present in the Building or on or under the real property 
upon which the Building is located; (xviii) except as provided in Section 
6(e)(2)(j) hereof, lease payments for  rented equipment, the cost of which 
equipment constitutes a capital expenditure if the equipment were purchased and 
any late fees, penalties, interest or similar fees incurred  in connection 
therewith; (xix)  any amounts paid to a person, firm or other entity related to 
Lessor which is in excess of the amount charged by unaffiliated parties for 
comparable goods or services; (xx)  except as provided in Section 6(e)(2)(j) 
hereof, costs incurred by Lessor to remedy any defects in the design or
materials used in the Building or Building equipment, or costs incurred by
Lessor to repair or replace the structural steel framing, roof, roofing systems,
foundations and underground utility lines forming a part of or servicing the 
Building; (xxi)  costs associated with the operation of the business of the 
entity which constitutes Lessor as the same are distinguished from the costs of 
operations of the Building, including, without limitation, accounting and legal 
expenses, costs of selling, syndicating, financing, mortgaging or hypothecating 
Lessor's interest in the Building, and costs of any disputes between Lessor and 
its employees or building managers; (xxii)  the cost of installing, operating 
and maintaining a specialty improvement, including, but not limited to, an 
observatory, athletic, luncheon or recreational club or facility; and (xxiii)
the value or lost income to Lessor of any office space in the Building which is 
utilized for the management of the Building; and (xxiv)  amounts paid as ground 
rental.
                         (l)  All revamping and reballasting in the
Common Areas of the Building; provided, however, that revamping and reballasting
in the Premises shall be performed by Lessor at Lessee's direction and at 
Lessee's sole cost and expense in accordance with Lessor's rate schedule in 
effect from time to time..
                         (m)   Lighting and maintenance of parking lot;
                              (n)  The cost of trash removal; and
                         (o)  An administrative fee equal to 10% of all
items contained in this paragraph as Additional Rent.
               (3). Base Cost.     The term Base Cost shall mean the
Operation and Maintenance Costs of the Building for the calendar year 1999.
               
          7.   Place of Payment.   All rents shall be payable to
Associates. without prior notice or demand at the office of Lessor c/o Keystone
Real Estate Management, Inc. 1150 First Avenue, King of Prussia, Pa. 19406 or at
such other place as Lessor may from time to time designate by notice in writing.

          8.   Affirmative Covenants of Lessee.   Lessee covenants and
agrees that it will, without demand:

               (a)  Payment of Rent.    Pay the rent and all other  charges
herein reserved as rent on the days and times and at the  place that the same 
are made payable, without fail, and if Lessor shall at any time or times accept
said rent or rent charges after the same shall have become due and payable, such
acceptance shall not excuse delay upon subsequent occasions, or constitute or be
construed as a waiver of any of Lessor's rights. Lessee agrees that any charge 
or payment herein reserved, included or agreed to be treated or collected as 
rent and/or any other charges or taxes, expenses, or costs herein agreed to be 
paid by the Lessee may be proceeded for and recovered by Lessor by distraint or 
other process in the same manner as rent due and in arrears.   In the event that
Lessee fails to make any payment due within five (5) days of its due date, 
Lessee shall pay a late charge to Lessor of ten cents for each dollar so 
overdue.  Such late charge shall be deemed additional rent for all purposes 
under this Lease.  Lessee shall also pay $50.00 for any returned check.

               (b)  Maintenance.   Keep the Premises clean and free from
all ashes, dirt and other refuse matter and shall repair all damages to the 
Premises for which Lessor is not insured which arise out the Lessee's negligence
or missuse of the Premises and not out of ordinary wear and tear to the 
Premises. The Lessee agrees to surrender the Premises in the same condition in 
which Lessee has herein agreed to keep same during the term of this Lease.   
Any repairs, replacements and renewals and/or any labor or materials performed 
or furnished in, on or about the Premises shall be performed or furnished in 
strict compliance with all applicable laws, regulations, ordinances and require-
ments of all duly constituted municipal authorities and/or other governmental 
bodies having jurisdiction and the requirements of the Board of Fire Under-
writers having jurisdiction hereof. 
          
               (c)  Requirements of Public Authorities.     Comply  with any
requirements of any of the constituted public authorities, and with the terms
of any
State or Federal statute  or local ordinance or regulation applicable to 
Lessee's specific manner of use of the Premises, including without limitation, 
the ADA and save Lessor harmless from penalties, fines, costs or damages 
resulting from failure to do so.
               (d)  Fire.     Use reasonable precaution against fire.
               (e)  Rules and Regulations.   Comply with rules and
regulations of Lessor promulgated as hereinafter provided so long as such
rules and
regulations are uniformly enforced against all tenants of the Building.
               (f)  Surrender of Possession.      Peaceably deliver up and
surrender possession of the Premises to the Lessor at the expiration or sooner
termination of this Lease, promptly delivering to Lessor at his office all
keys for the
Premises.
               (g)  Notice of Fire, etc.     Give to Lessor prompt written
notice of any accident, fire, or damage occurring on or to the Premises.
               (h)  Common Areas.   Lessor and all tenants shall have the
right to use the common areas of the Building.  Such right of use shall include
Lessee, its employees, agents, invitees and licensees.  Lessor shall have the 
right from time to time to establish, modify and enforce reasonable rules and 
regulations with respect to such areas, facilities and improvements, and to 
change the location of or otherwise alter or modify any of the common areas, 
facilities and improvements, so long as Lessor continues to provide adequate 
passage way to the Premises and does not interfere with Lessee's use and 
enjoyment of the Premises.  Lessee shall comply with all such reasonable rules 
and regulations so long as such rules and regulations are uniformly enforced 
against all tenants of the Building.
 
          9.   Negative Covenants of Lessee.      Lessee covenants and agrees
that it will do none of the following things without the prior consent in
writing of Lessor, which consent shall not be unreasonably withheld, conditioned
or delayed:

               (a)  Use of Premises.    Occupy the Premises in any  other
manner or for any purpose other than as above set forth.
               (b)  Assignment and Sub-letting.   Assign, mortgage or
pledge this Lease or under-let or sublease the Premises, or any part thereof, or
permit any other person, firm or corporation to occupy the Premises, or any part
thereof; nor shall any assignee or sublessee assign, mortgage or pledge this 
Lease or such sublease, without an additional written consent by Lessor, which 
Lessor may not unreasonably withhold.  Notwithstanding the foregoing, Lessee 
shall not be required to obtain Lessor's consent in connection with an 
assignment or sublease to any entity controlling, controlled by or under common 
control with Lessee or to any successor to Lessee by reason  of a merger, sale 
of all or substantially all of the assets of Lessee or transfer of a controlling
percentage of the corporate stock of Lessee, provided Lessee shall give Lessor 
written notice of any such assignment or sublease, including the effective date 
thereof, within thirty (30) days following such effective date and further 
provided that the use of the Premises by such assignee or subleassee shall be 
permitted under this Lease 
               (c)  Signs.    Place or allow to be placed any stand, booth,
sign or show case upon the doorsteps, vestibules or outside walls or pavements 
of the Premises, or paint, place, erect or cause to be painted, placed or 
erected any sign, projection or device on or in any part of the Premises which 
is visible from outside the Premises.  Lessee shall remove any sign, projection 
or device painted, placed or erected if permission has been granted and restore 
the walls, etc., to their former conditions, at or prior to the expiration of 
this Lease. In case of the breach of this covenant (in addition to all other 
remedies given to Lessor in case of breach of any conditions or covenants of 
this Lease), Lessor shall have the privilege of removing said stand, booth, 
sign, show case, projection or device, and restoring said walls, etc., to their 
former condition, and Lessee, at Lessor's option, shall be liable to Lessor for 
any and all expenses so incurred by Lessor. 
               (d)  Alterations, Improvements. Make any alterations,
improvements, or additions to the Premises. All alterations, improvements,
additions or fixtures, whether installed before or after the execution of this 
Lease, shall remain upon the Premises at the expiration or sooner termination of
this Lease and become the property of Lessor.  In the event Lessee shall make 
any alterations, improvements or additions to the Premises without Lessor's 
consent, if Lessor shall, prior to the termination of this Lease, have given 
written notice to Lessee to remove same, Lessee will remove such alterations, 
improvements and additions and restore the Premises to the same condition in 
which Lessee has herein agreed to keep same during the term of the Lease.   
Should Lessee fail so to do, Lessor may do so, collecting, at Lessor's option, 
the cost and expense thereof from Lessee as additional rent.  Notwithstanding 
the foregoing, Lessee can make any alterations, additions or improvements up to 
$2,500.00 per item or anything cosmetic, without Lessor's written approval.
               
               (e)  Mechanics Liens.     Prior to the commencement of any
work to be performed by or on behalf of Lessee on the Premises for which a lien
could be filed against the Premises or the Building, Lessee shall execute and 
either duly record and file, or at Lessor's request, deliver to Lessor for 
recording and filing, a waiver of mechanics' liens for itself and all contrac-
tors, mechanics, materialmen and subcontractors retained by, on behalf of or 
taking under Lessee, in form and substance satisfactory to Lessor.  If recorded 
or filed by Lessee, Lessee shall deliver a copy thereof to Lessor with the 
recording information, prior to the commencement of any such work on the 
Premises.  Lessee shall execute and deliver substitute, duplicate original and 
additional of such waivers from time to time upon Lessor's request.  Prior to 
any mechanic, materialman, laborer, artisan, contractor, subcontractor, 
architect, engineer, surveyor, or other person afforded protection or benefits 
under all applicable mechanics lien laws (separately and collectively, 
"mechanic"), performing any work or supplying any materials whatsoever, Lessee 
shall first cause to be duly executed by every such mechanic a waiver of liens 
in form and substance reasonably acceptable to Lessor, and either cause such 
waivers to be duly and properly filed and recorded in all places, in such manner
and within such time, prior to commencement of work or supplying of material, as
is prescribed by law, or cause delivery thereof to be made upon Lessor at least 
ten (10) business days prior to any work being done at or materials being 
supplied to the Premises.  Lessor shall promptly provide Lessee with a waiver of
liens form acceptable to Lessor.
          Lessee shall keep the Premises and all other parts of the Building 
free from any and all liens arising out of any work performed, services, 
supplies, labor or materials furnished or obligations incurred by or for Lessee 
(but not by Lessor or its contractors), or Lessee's operations and Lessee agrees
to discharge, by payment, bonding, order of a court of competent jurisdiction or
otherwise, such mechanics' or materialmen's liens, within sixty (60) days after 
request therefore by Lessor, or such shorter period if the liens or any of them 
are in any manner materially impeding, jeopardizing or delaying a potential 
sale, leasing, financing, refinancing and/or extension of credit of or to the 
Building or part thereof.  If Lessee fails to do so, Lessor may do what it deems
appropriate to protect its interests and Lessee shall reimburse Lessor for any 
and all costs and expenses (including reasonable attorneys' fees and all related
costs, together with interest thereon at the rate of thirteen percent (13%) from
the date of Lessor's making of all payments and incurring of the costs and 
expenses) which may be incurred by Lessor by reason of the filing of any such 
liens and/or the removal of same; such reimbursements shall be considered Addit-
ional Rent and shall be made within thirty (30) days after demand by Lessor 
setting forth the amount of such costs and expenses.  All materialmen, 
contractors, artisans, mechanics, laborers and any other persons now or here-
after contracting with Lessee for the furnishing of any labor, services, 
materials, supplies or equipment with respect to any portion of the Building,
at any time from the date hereof until the end of the term are hereby charged 
with notice that they must look exclusively to Lessee to obtain payment for such
service or material, and Lessee shall communicate the same in writing to every 
such mechanic, materialman, contractor, artisan, laborer, and similar person 
with which it deals with respect to the Building.
          Lessee shall indemnify and hold Lessor harmless, and defend Lessor,
at Lessee's sole cost and expense, utilizing counsel reasonably approved by 
Lessor, from and against any and all losses, liabilities, judgments, liens, 
claims, costs, damages and expenses incurred or suffered by Lessor, including 
without limitation, all reasonable legal fees and costs incurred in connection 
therewith, arising out of or relating to any mechanics' or materialmen's lien 
(other than ones caused by Lessor) upon the Premises in  breach of this Section
of the Lease. 
          Nothing contained in this Lease shall be deemed or construed in any
way as constituting the consent or request of Lessor, express or implied by
inference or otherwise, to any contractor, subcontractor, laborer or
materialman for
the performance of any labor or the furnishing of any materials for any specific
alteration, addition, improvement or repair to the Building or the Premises or 
any part thereof, nor as giving Lessee any right, power or authority to contract
for or permit the rendering of any services or the furnishing of any materials 
that would give rise to the filing of any lien against the Building or the 
Premises or any part thereof, nor as evidencing Lessor's consent that the 
Premises may be subject to any mechanic's, laborer's or materialman's lien.
               (f)  Machinery.     Use or operate any machinery that, in
Lessor's reasonable opinion, is harmful to the Premises or disturbing to other
tenants occupying adjacent premises.
               (g)  Weights.  Place any weights in any portion of the
Premises beyond the safe carrying capacity of the structure. 
               (h)  Fire Insurance.     Do or suffer to be done, any act,
matter or thing objectionable to the fire insurance companies whereby the fire
insurance or any other insurance now in force or hereafter to be placed on the
Premises, or any part thereof, or on the building of which the Premises may be a
part, shall become void or suspended, or whereby same shall be rated as a more
hazardous risk than at the date of execution of this Lease, or employ any
person or persons objectionable to the fire insurance companies or carry or have
any benzine or explosive matter of any kind in and about the Premises. In case 
of a breach of this covenant (in addition to all other remedies given to Lessor 
in case of the breach of any of the conditions or covenants of this Lease), 
Lessee agrees to pay to Lessor as additional rent any increases of premiums on 
insurance carried by Lessor on the Premises, or any part thereof, or on the 
building of which the Premises may be a part, caused thereby.
               (i)  Environmental Matters.   Lessee shall not engage in
operations at the Premises which involve the generation, manufacturing, 
refining, transportation, treatment, storage, handling, or disposal of 
"hazardous substances" or "hazardous waste," without the prior written consent 
of Lessor, which consent shall be at Lessor's sole discretion without regard to 
reasonableness.  Medical waste shall be disposed of by companies licensed to do 
so.  Lessee agrees to hold the Lessor harmless from all costs, fines, and/or 
penalties, which may result from the presence of hazardous waste or hazardous 
materials on the Premises attributable to the period of the Lessee's occupancy 
and arising by reason of a violation by Lessee of this Section 9(i).   Lessor 
has an environment Phase I report prepared by Philips Services dated June, 1997,
which is available to Lessee to review.

          10.  Lessor's Rights.    Lessee covenants and agrees that Lessor
shall have the right to do the following things and matters in and about the
Premises:

               (a)  Inspection, Repair and Alteration of Premises. At all
reasonable times, and upon reasonable advance notice,  by itself or by  its duly
authorized agents to go upon and inspect the Premises and every part thereof, 
and at its sole option to make repairs, alterations, renovations and additions 
to the Premises, or to the Building of which the Premises is a part.
               (b)  Rules and Regulations.   At any time or times and from
time to time to make such rules and regulations as in its judgment may from time
to time be necessary for the safety, care and cleanliness of the Premises, and 
for the preservation of good order therein. Such rules and regulations shall, 
when notice thereof is given to Lessee, form a part of this Lease.
               (c)  Sale or Rent.  To display a "For Sale" sign at any
time, and also, after notice from either party of intention to terminate this
Lease, or at any time within three months prior to the expiration of this Lease,
a "For Rent" sign, or both "For Rent" and "For Sale" signs; and all of said 
signs shall be placed upon such part of the Premises as Lessor may elect and may
contain such matter as Lessor shall require.  Prospective purchasers of the 
Building or after notice from either party of its intention to terminate this 
Lease, or within 3 months prior to the expiration of this Lease, prospective 
tenants authorized by Lessor, may inspect the Premises at reasonable hours after
reasonable advance notice.
               (d)  Discontinue Facilities and Service.      The Lessor may
discontinue all facilities furnished and services rendered, or any of them, by 
Lessor, not expressly covenanted for herein, it being understood that they 
constitute no part of the consideration for this Lease.

          11.  Responsibility of Lessee.

               (a)  Lessee agrees to be responsible for and to relieve and
hereby relieves Lessor from all liability by reason of any injury or damage to 
any person or property in the Premises, whether belonging to the Lessee or any 
other person, caused by any fire, breakage or leakage in any part or portion of 
the Premises, or any part or portion of the building of which the Premises is a
part, or from water, rain or snow that may leak into, issue or flow from any 
part of the Premises, or of the building of which the Premises is a part, or 
from the drains, pipes or plumbing work of the same, or from any place or 
quarter, unless such breakage, leakage, injury or damage is  caused by or 
results from the gross negligence or willful misconduct of Lessor or its 
officers, employees, agents, independent contractors.
               (b)  Lessee also agrees to be responsible for and to relieve
and hereby relieves Lessor from all liability by reason of any damage or
injury to any person or thing which may arise from or be due to the use, misuse 
or abuse by Lessee of all or any of the elevators, hatches, openings, stairways,
hallways, of any kind whatsoever, which may exist or hereafter be erected or 
constructed on the Premises or from any kind of injury which may arise from 
Lessee's use, misuse or abuse of the Premises or the building of which the 
Premises is a part. 

          12.  Responsibility of Lessor.

               (a)  Destruction of Premises.      In the event that the
Premises is destroyed or damaged by fire or other casualty then Lessor shall 
with reasonable promptness (taking into account the nature of the damage and 
time it takes for the insurance carrier to investigate and pay for the loss) 
repair or restore the Premises to substantially the same condition and quality 
they were in immediately prior to the casualty;  provided that if substantially 
all of such damages is not practically repairable or is not actually repaired, 
within one hundred and twenty (120) days after the casualty in question Lessee 
may, by notice to Lessor, terminate this Lease and the tenancy hereby created 
shall cease (i) as of the date of the casualty, the rent to be adjusted as of 
such date, if Lessee has been unable to occupy the Premises or (ii) as of the 
date of such notice, if Lessee has reoccupied the Premises pursuant to interim 
repairs.  Promptly after any casualty, Lessee shall take interim steps to render
the Premises usable to the maximum extent possible. 
Notwithstanding the preceding, if the damage to the Premises shall render the
whole or any material part thereof unsuitable for the use for which they were
intended and theretofore employed, a just proportion of the rent, according to 
the nature and extent of the deprivation, shall be suspended until the Premises
(or the portion for which rent suspension applies) shall be repaired or restored
by Lessor to substantially the same quality they were in immediately prior to 
such casualty.  If the insurance proceeds plus the policy "deductible" should be
less than the cost of the repair or restoration, Lessor shall pay the excess 
cost to a maximum of $10,000.  In this event, Lessor shall have the option of 
fully restoring the Premisesompt notice to Lessee of its election not to so 
restore the Premises, in which event, upon thirty (30) days notice, Lessee will 
have the right to terminate this Lease.  If the insurance proceeds shall be 
greater than the cost of repair or restoration, the excess shall belong to 
Lessor.  However, if Lessor is unable to collect the insurance proceeds, after 
all reasonable actions to pursue its claims, Lessor shall not be obligated to 
rebuild the Premises and, upon 30 days notice to Lessee, may terminate this 
Lease.   
               (b)  No Damage for Interruption of Use.  Lessor  shall not
be liable for any damage, compensation or claim by reason of inconvenience or
annoyance arising from the necessity of repairing any portion of the Premises
or the
interruption in the use of the Premises, nor shall rent abate.
               (c)  Conditions of Premises.  It is understood and agreed that
Lessor is under no duty to make repairs or alterations at the time of letting
or at any
time thereafter; except as specifically set forth hereinafter.  Lessor shall
make at its
sole cost and expense, all repairs necessary to initially provide to the
Premises and
thereafter to maintain, in safe condition and in compliance with all
applicable laws
and regulations, plumbing, air conditioning and electrical systems, windows, 
floors (except carpeting) and all other items which constitute a part of the 
Building structure and are installed or furnished by Lessor, which shall be 
sufficient for Lessee's intended use of the Premises for the office purposes; 
provided, however, that Lessor shall not be obligated for any of such repairs 
until the expiration of a reasonable period of time after written notice from 
Lessee that such repair is needed.   Lessor shall be responsible for compliance 
with all applicable laws, other than those applicable to Lessee's alterations or
other improvements made by Lessee, and will provide all State approved plans for
the Premises.   Lessee shall be responsible for compliance with laws applicable 
to alterations or other improvements made by Lessee.       
               (d)  Quiet Enjoyment.     Upon payment by Lessee of all rents
and other charges herein provided, and upon the observance and performance of 
all the covenants, terms, and conditions on Lessee's part to be observed and
performed, Lessee shall peacefully and quietly hold and enjoy the Demised 
Premises for the term hereof without hindrance or interruption by Lessor or any 
other person or persons lawfully or equitably claiming by, through or under the 
Lessor, except as otherwise provided in this Lease.  
               (e)  Building Services.
                    (1)  The following services and facilities shall be
supplied by Lessor in accordance with the terms of this Lease, in connection 
with Lessee's use of the Premises,  or in common with the other tenants of the 
Building, as applicable:
                         (i)  Heat, ventilation, and air conditioning for the
Premises and the common areas of the Building;
                         (ii) Janitorial service on Business Days;
                         (iii)     Listing of Lessee's name of a Building
directory in the Building lobby;
                         (iv) Electricity to the Premises and to all common
areas of the Building;
                         (v)  Trash collection and removal,  landscaping
and snow removal; and 
                    (2)  Lessor's services shall be provided at a level and in
a manner consistent with the operation of  comparable office buildings in the
competitive area of the Building.
                    (3)  "Business Day(s) shall mean Mondays through Fridays 
exclusive of the normal holidays of New Year's Day, Memorial Day, Independence 
Day, Labor Day, Thanksgiving Day and Christmas Day.
          13.  Miscellaneous Agreements and Conditions.

               (a)  Effect of Repairs on Rental.  No contract entered into
or that may be subsequently entered into by Lessor with Lessee, relative to any
alterations, additions, improvements or repairs, nor the failure of Lessor to 
make such alterations, additions, improvements or repairs as required by any 
such contract, nor the making by Lessor or his agents or contractors of such 
alterations, additions, improvements or repairs shall in any way affect the 
payment of the rent or said other charges at the time specified in this Lease.
               (b)  Agency.   Each party represents to the other that it has
not dealt with any agent or broker in connection with this Lease other than
Keystone Real Estate Management, Inc. and hereby indemnifies the other party
against any damages incurred as a result of a misrepresentation contained in 
this Subparagraph 13(b).  Lessor shall be responsible for  commissions owing to
Keystone Real Estate Management, Inc..
               (c)  Waiver of Custom.   It is hereby covenanted and
agreed, any law, usage or custom to the contrary notwithstanding, that Lessor 
shall have the right at all times to enforce the covenants and provisions of 
this Lease in strict accordance with the terms hereof, notwithstanding any 
conduct or custom on the part of Lessor in refraining from so doing at any time
or times; and, further, that the failure of Lessor at any time or times to 
enforce its rights under said covenants and provisions strictly in accordance 
with the same shall not be construed as having created a custom in any way or 
manner contrary to the specific terms, provisions and covenants of this Lease or
as having in any way or manner modified the same.
               (d)  Conduct of Lessee.  This Lease is granted upon the
express condition that Lessee and/or the occupants of the Premises shall not 
create a public nuisance and that if at any time during the term of this Lease 
or any extension or continuation thereof, Lessee or the occupier of the Premises
shall have created a public nuisance (after notice and a reasonable cure 
period), Lessee shall be taken to have broken the covenants and conditions of 
this Lease, and Lessor will be entitled to all of the rights and remedies 
granted and reserved herein for the Lessee's failure to observe all of the 
covenants and conditions of this Lease.
               (e)  Failure of Lessee to Repair.  In the event of the failure
of Lessee promptly to perform the covenants of subparagraph 8(b) and (c) hereof,
Lessor may go upon the Premises and perform such covenants. The cost thereof, at
the sole option of Lessor, shall be charged to Lessee as additional and
delinquent rent.

          14.  Remedies of Lessor.      If  Lessee:

               (a)  Does not pay in full when due any and all installments of
rent and/or any other charge or payment herein  reserved, included, or agreed
to be treated or collected as rent and/or any other charge, expense, or cost 
herein agreed to be paid by Lessee, after notice and a cure period of five (5) 
days; or
               (b)  Violates or fails to perform or otherwise breaks any
covenant or agreement herein contained where such violation or failure continues
for fifteen (15) days after written notice thereof from Lessor to Lessee 
provided, however, that if the nature of the violation or failure is such that 
the same cannot reasonable be cured within such fifteen (15) days period, Lessee
shall not be deemed in  default if Lessee shall within such period commence such
cure and thereafter diligently prosecute the same to completion; or
               (c)  Becomes insolvent, or makes an assignment for the
benefit of creditors, or if a petition in bankruptcy is filed by or against
Lessee, or a bill in equity or other proceeding for the appointment of a 
receiver for Lessee is filed, or if proceedings for reorganization or for compo-
sition with creditors under any State or Federal law be instituted by or against
Lessee, or if the real or personal property of Lessee shall be sold or levied 
upon by any Sheriff, Marshall or Constable; then and in any or either of said 
events set forth in this Paragraph 14, there shall be deemed to be a breach of 
this Lease, and thereupon ipso facto and without entry or other action by 
Lessor,  provided, however, that if any such action is commenced against Lessee 
the  same shall not constitute a default if Lessee causes the same to be stayed 
or dismissed within sixty (60) days after the filing of same.
                    (1)  Without terminating this Lease, Lessor may declare
the rent for the entire unexpired balance of the term of this Lease, including 
any option terms as to which notice has been provided by Lessee, as well as all 
other charges, payments, costs and expenses herein agreed to be paid by the 
Lessee, or at the option of Lessor any part thereof, and also all costs and 
officer's commissions including watchmen's wages and further including the five 
percent chargeable by Act of Assembly to Lessor, shall, in addition to any and 
all installments of rent already due and payable and in arrears and/or any other
charge of payment herein reserved, included or agreed to be treated or collected
as rent, and/or any other charge, expense or cost herein agreed to be paid by 
Lessee which may be due and payable and in arrears, be taken to be due and 
payable and in arrears as if by the terms and provisions of this Lease, the 
whole balance of unpaid rent and other charges, payments, taxes, costs and 
expenses were on that date payable in advance; and if this Lease or any part 
thereof is assigned, or if the Premises or any part thereof is sublet, Lessee 
hereby irrevocably constitutes and appoints Lessor Lessee's agent to collect the
rents due by such assignee or sublessee and apply the same to the rent due here-
under without in any way affecting Lessee's obligation to pay any unpaid balance
of rent due hereunder; or 
                    (2)  Lessor may serve notice upon Lessee that this
Lease and the term hereby created, including all option terms hereunder, shall
terminate and become absolutely void as of the date specified in the notice,
to be not less than five (5) days after delivery of the notice to Lessee, 
without any right on the part of Lessee to save the forfeiture by payment of any
sum due or by other performance of any condition, term or covenant broken; 
whereupon, Lessor shall be entitled to recover damages for such breach in an 
amount equal to the amount of rent reserved for the balance of the term of this 
Lease including any option terms as to which Lessee has provided notice.

          15.  Further Remedies of Lessor.   In the event of any default as
above set forth in Paragraph 14, Lessor, or anyone acting on Lessor's behalf, at
Lessor's option:

               (a)  may without notice or demand enter the Premises,
breaking open locked doors if necessary to effect entrance, without liability to
action for prosecution or damages for such entry or for the manner thereof,
for the
purpose of distraining or levying and for any other purposes, and take
possession of
and sell all goods and chattels at auction, on three days' notice served in
person on
the Lessee or left on the Premises, and pay Lessor out of the proceeds all sums
due.  Even if the rent is not due at that time, should the Lessee at any time 
remove or attempt to remove goods and chattels from the Premises without leaving
enough thereon to meet the next periodical payment, Lessee authorizes Lessor to 
pursue Lessee for a period of ninety days after such removal, take possession of
and sell at auction, upon like notice, sufficient of such goods to meet the 
proportion of rent accrued at the time of such removal.  Lessee hereby releases 
and discharges Lessor, and its agents, from all claims, actions, suits, damages,
and penalties, for or by reason or on account of any entry, distraint, levy, 
appraisement or sale; and/or 
               (b)  may enter the Premises, and without demand proceed by
distress and sale of the goods there found to levy the rent and/or other charges
herein payable as rent, and all costs and officer's commissions, including
watchmen's wages and sums chargeable to Lessor, and further including a sum
equal to 5% of the amount of the levy as commissions to the constable or other
person making the levy, shall be paid by the Lessee, and in such case all costs,
officer's commission and other charges shall immediately attach and become part
of the claim of Lessor for rent, and any tender of rent without said costs,
commission and charges made after the issue of a warrant of distress shall not 
be sufficient to satisfy the claim of the Lessor. Lessee hereby expressly waives
in favor of Lessor the benefit of all laws now made or which may hereafter be 
made regarding any limitation as to the goods upon which, or the time within 
which, distress is to be made after the removal of goods, and further relieves 
the Lessor of the obligations of proving or identifying such goods, it being the
purpose and intent of this provision that all goods of Lessee, whether upon the 
Demised Premises or not, shall be liable to distress for rent. Lessee waives in 
favor of Lessor all rights under the Act of Assembly of April 6, 1951, P. L. 69,
and all supplements and amendments thereto that have been or may hereafter be 
passed, and authorizes the sale of any goods distrained for rent at any time 
after five days from said distraint without any appraisement and/or condemnation
thereof and Lessee also waives the right to issue a Writ of Replevin under the 
Pennsylvania Rules of Civil Procedure, No 1071 &c. and Laws of the Commonwealth 
of Pennsylvania, or under all other law previously enacted and now in force, or 
which may be hereafter enacted, for the recovery of any articles, household 
goods, furniture, etc. seized under a distress for rent or levy upon an execu-
tion for rent, damages or otherwise; all waivers herein before mentioned are 
hereby extended to apply to any such action; and/or 
               (c)  may lease the Premises or any part or parts thereof to
such person or persons as may in Lessor's discretion seem best and the Lessee
shall be liable for any loss of rent for the balance of the then current term.

          16.  DUTY TO MITIGATE.   In exercising its rights hereunder,
Lessor shall have a duty to mitigate its damages provided that such efforts
shall not
require Lessor to let the Premises to any party not meeting its qualifications
standards, provided such standards have been and are being applied uniformly.  
Efforts by Lessor to mitigate its damages shall not constitute a waiver of any 
right or remedy available to Lessor.

          17.  CONFESSION OF EJECTMENT.      When this Lease shall be
terminated by condition broken, either during the original term of this Lease
or any
renewal or extension thereof, and also when and as soon as the term hereby
created or any extension thereof shall have expired, it shall be lawful for any
attorney as attorney for Lessee to file an agreement for entering in any 
competent Court an action and judgment in ejectment against Lessee and all 
persons claiming under Lessee for the recovery by Lessor of possession of the 
herein Demised Premises, for which this Lease shall be his sufficient warrant, 
whereupon, if Lessor so desires, a Writ of Execution or of Possession may issue 
forthwith, without any prior writ or proceedings whatsoever, and provided that 
if for any reason after such action shall have been commenced the same shall be 
determined and the possession of the Premises remain in or be restored to 
Lessee, Lessor shall have the right upon any subsequent default or defaults, or 
upon the termination of this Lease as hereinbefore set forth, to bring one or 
more amicable action or actions as hereinbefore set forth to recover possession 
of the Premises. 

          18.  Affidavit of Default.    In any action of ejectment Lessor shall
first cause to be filed in such action an affidavit made by it or someone
acting for it
setting forth the facts necessary to authorize the entry of judgment, of which 
facts such affidavit shall be prima facie evidence, and if a true copy of this 
Lease (and of the truth of the copy such affidavit shall be sufficient evidence)
be filed in such action, it shall not be necessary to file the original as a 
warrant of attorney, any rule of Court, custom or practice to the contrary 
notwithstanding.

          19.  Remedies Cumulative.     All of the remedies herein before
given to Lessor and all rights and remedies given to it by law and equity
shall be
cumulative and concurrent. No termination of this Lease or the taking or 
recovering of the Premises shall deprive Lessor of any of its remedies or 
actions against Lessee for rent due at the time or which, under the terms 
hereof, would in the future become due as if there has been no termination, or 
for any and all sums due at the time or which, under the terms hereof, would in 
the future become due as if there had been no determination, nor shall the 
bringing of any action for rent or breach of covenant, or the resort to any 
other remedy herein provided for the recovery of rent be construed as a waiver 
of the right to obtain possession of the Premises.

          20.  Condemnation.  In the event that the Premises or any part
thereof is taken or condemned for a public or quasi public use, this Lease
shall, as to the part so taken, terminate as of the date title shall vest in the
condemnor, and rent shall abate in proportion to the square feet of leased space
taken or condemned or shall cease if the entire Premises be so taken. In either 
event, Lessee waives all claims against Lessor by reason of the complete or 
partial taking of the Premises, and it is agreed that Lessee shall not be 
entitled to any notice whatsoever of the partial or complete termination of this
Lease by reason of the aforesaid.  In the event a portion only of the Premises 
or a portion of the Building shall be so taken such as to have a material 
adverse impact upon Lessee's use and enjoyment of the Premises, then within 
thirty (30) days thereafter, either Lessee or Lessor may elect to terminate  
this Lease from the date when possession is so taken.  If no such election is 
made, Lessor shall repair and restore, at its own expense, the portion not taken
and thereafter the rent shall be reduced proportionately to the portion of the 
Premises taken.
 
          21.  Subordination.      This Lease is subject and subordinate to any
and all mortgages now or hereafter placed upon the property of which the 
Premises is a part, and to all renewals, modifications and extensions thereof.  
Lessee agrees upon demand of Lessor to execute, acknowledge and deliver all such
instruments as shall be requested by any mortgagee or proposed mortgagee to 
confirm such subordination, if requested by any mortgagee.  However, such 
subordination shall be conditioned on Lessor delivering a non-disturbance agree-
ment from such mortgagee, substantially in the form of Exhibit I hereto, to the 
effect that Lessee's possession and quiet enjoyment of the Premises shall not be
disturbed so long as Lessee performs its obligations hereunder.

          22.  Insurance.

               (a)  Lessor shall keep the Premises continuously insured
against loss or damage by fire, with extended coverage, and against such other
hazards as Lessor may reasonably require for its full replacement value.  In 
addition, Lessor shall carry comprehensive public liability insurance on all 
common areas in amounts reasonably determined by Lessor.  
               (b)  Lessee shall maintain or cause insurance to be maintained
as follows:
                    (i)  Comprehensive public liability insurance an
"occurrence basis" against claims for "personal injury", including without 
limitation bodily injury, death or property damage occurring on, in or about the
Premises and the adjoining streets, sidewalks and passageways, such insurance to
afford immediate minimum protection to a limit of not less than that required 
by Lessor with respect to personal injury or death to any one or more persons 
(not less than $2,000,000) or damage to property (not less than $500,000);
                    (ii)  Worker's compensation insurance, including
employer's liability insurance, for all employees of Lessee engaged on or with
respect to the Premises in such amount as is reasonably satisfactory to
Lessor, or, if such limits are established by law, in such amounts;
                    (iii)     During the course of any construction or repair of
improvements on the Premises by Lessee (if permitted by Lessor), builder's
completed value risk insurance against "all risks of physical loss", including 
collapse and transit coverage, during construction of such improvements, with 
deductibles not to exceed $l,000, in non-reporting form, covering the total 
value of work performed and equipment, supplies and materials furnished. Such 
policy of insurance shall contain the "permission to occupy upon completion of 
work or occupancy" endorsement;
                    (iv) Such other insurance, and in such amounts, as
may from time to time be reasonably required by Lessor against the same or other
hazards.
               (c)  All policies of insurance required by the  terms of
subparagraph 24(a) or (b) shall contain an endorsement or agreement by the 
insurer that any loss  shall be payable in accordance with the terms of such 
policy notwithstanding any act or negligence of Lessee or Lessor which might  
otherwise result in forfeiture of such insurance and the further  agreement of 
the insurer waiving all rights of set-off, counterclaim or deductions against 
Lessee and Lessor.
               (d)  All policies of insurance shall be issued by companies and
in amounts in each company reasonably satisfactory to Lessor. All policies of
insurance shall where possible name Lessor, and, if appropriate the holder of 
any mortgage upon the Premises, as an additional insured or as additional loss 
payee, not subject to contribution, all in form reasonably satisfactory to 
Lessor. Lessee shall furnish Lessor with a signed duplicate original policy with
respect to all required insurance coverage. At least thirty (30) days prior to 
the expiration of each such policy, Lessee shall furnish Lessor with evidence 
reasonably satisfactory to Lessor of the payment of premium and the reissuance 
of a policy continuing insurance in force as required by this Lease. All such 
policies, including policies for any amounts carried in excess of the required 
minimum and policies not specifically required by Lessor, shall be in form 
reasonably satisfactory to Lessor, shall be maintained in full force and effect,
shall be delivered to Lessor, with premiums prepaid, as collateral security for 
payment of the obligations of Lessee hereunder, and shall contain a provision 
that such policies will not be canceled or materially amended, which term shall 
include any reduction in the scope or limits of coverage, without at least 
thirty (30) days prior written notice to Lessor. If the insurance, or
any part thereof, shall expire, or be withdrawn, or become void or unsafe by 
reason of Lessee's breach of any condition thereof, or become void or unsafe by
reason of
the value or impairment of the capital of any company in which the insurance may
then be carried, or if for any reason whatever the insurance shall be unsatis-
factory to Lessor in its reasonable judgment , Lessee shall place new insurance 
on the Premises, reasonably satisfactory to Lessor.
               (e)  In the event Lessee fails to provide, maintain, keep in
force or deliver and furnish to Lessor the policies of insurance required by 
this Lease, Lessor may procure such insurance or single interest insurance for 
such risks covering Lessor's interest, and Lessee will pay all premiums thereon 
promptly upon demand by Lessor, and until such payment is made by Lessee the 
amount of all such premiums, together with interest thereon at the lesser of the
highest legal rate of interest or thirteen percent (13%) per annum, shall be due
and payable hereunder.

          23.  Notices.  All notices required hereunder shall be given by
certified mail, return receipt requested and shall be deemed effective three
(3) days
after the date of receipt. Any notices to Lessor shall be addressed to: Keystone
Real Estate Management, Inc., 1150 First Avenue,  King of Prussia, Pa. 19406. 

          24.  Lease Contains All Agreements.     It is expressly understood
and agreed by and between the parties that this Lease and the riders attached 
and forming a part hereof set forth all the promises, agreements, conditions and
understandings between Lessor or its Agents and Lessee relative to the Premises,
and that there are no promises, agreements, conditions or understandings, either
oral or written, between them other than are herein set forth. It is further
understood and agreed that, except as herein otherwise provided, no subsequent
alteration, amendment, change or addition to this Lease shall be binding upon
Lessor or Lessee unless reduced to writing and signed by them.

          25.  Successors and Assignees.     All rights and liabilities herein
given to, or imposed upon, the respective parties shall extend to and bind the
several and respective successors and assigns of the parties; and if there
shall be more than one Lessee, they shall all be bound jointly and severally by 
the terms, covenants and agreements herein, and the word "Lessee" shall be 
deemed and taken to mean each and every person or party mentioned as a Lessee 
herein, be the same one or more; and if there shall be more than one Lessee, any
notice required or permitted by the terms of this Lease may be given by or to 
any one thereof, and shall have the same force and effect as if given by or to 
all thereof. No rights, however, shall inure to the benefit of any assignee of 
Lessee unless the assignment to such assignee has been approved by Lessor in 
writing as aforesaid.  
          
          26.  Security Deposit.   Upon the execution of this lease, Lessee
shall deposit with Lessor a security deposit of     Six Thousand   and  Ten 
Dollars and    66/100 ($6,010.66)  Upon the occurrence of any Event of Default 
by Lessee, Lessor may from time to time and without prejudice to any other 
remedy, use the security deposit to the extent necessary to make good any 
arrears of  base rent or additional rent, or any other damage, injury, expense 
or liability caused to Lessor by such Event of Default, any remaining balance of
such security deposit to be returned by Lessor to Lessee within a reasonable 
period of time after the termination of this Lease.  However, the security 
deposit shall not be considered an advance payment of rental or a measure of 
Lessor's damages in case of default by Lessee.  Lessee shall be entitled to 
receive and shall receive no interest on such security deposit, and Lessor may 
commingle the same with other monies of Lessor. 
If Lessor shall ever use the security deposit to pay the sums described above,
Lessee shall immediately deposit with Lessor an additional security deposit
equal to the amount so used.

          27.  Estoppel Certificates.   Lessor and Lessee agree to execute
and deliver to the other (or a designee thereof) within seven 7 days at the 
request therefore, a statement, in writing and in recordable form, certified to 
the extent true:  (i) that this Lease is in full force and effect and unmodified
(or, if so modified, stating the modifications) (ii) Lessee has accepted the 
Premises; (iii) the commencement and expiration date at the term of this Lease; 
(iv) that rental payments are current without any offset or defense thereto if 
correct, or if not correct, a statement setting forth the correct information; 
(v) the amount of rent and security deposit, if any, paid in advance; (vi) that 
to the knowledge of the officer executing the statement, Lessor and Lessee 
respectively are not in default in performance of obligations under this Lease 
or if they are in default, specify in which respects the Lessor or Lessee is in 
default; and (vii) any other matter relating to the status of this Lease which 
may be reasonably requested.

          28.  Agency.        It is expressly understood and agreed by
Lessor and Lessee that Keystone Real Estate Management, Inc. and Prentice
Properties Management are acting only as an agent and shall not in any event be
liable either to Lessor or Lessee for the fulfillment or non-fulfillment of
any of the
terms, covenants, conditions or provisions of this Lease or for any action or
proceeding taken by Lessor against Lessee or by Lessee against Lessor.

          29.  Force Majeure.      Lessor and Lessee shall be excused for
the period of any delay in its performance of any of the obligations hereunder,
when prevented from so doing by cause or causes beyond Lessor's control which
shall include, without limitation, all labor disputes, inability to obtain
material or
services, civil commotion, or Acts of God.

          30.  Lessor's Obligations.    Lessor's obligations hereunder shall be
binding upon Lessor only for a period of time that Lessor is in ownership of the
Building; and, upon termination of that ownership, Lessee, except as to any
obligations which have then matured, shall look solely to Lessor's successor in
interest in the Building for the satisfaction of each and every obligation of 
Lessor hereunder, provided this Lease is assumed by such successor in interest 
by separate written agreement or by operation of law.

          31.  Lessor's Liability. Lessor shall have no personal liability under
any of the terms, conditions or covenants of this Lease, and Lessee shall look 
solely to the equity of the Lessor in the Building of which the Premises form a 
part for the satisfaction of any claim, remedy or cause of action occurring to 
Lessee as a result of the breach of any portion of this Lease by Lessor.

          32.  Waiver of Jury Trial.    Lessee hereby waives trial by jury in
the event that any litigation is instituted under this Lease.

          33.  Corporate Authority.     The undersigned person executing on
behalf of Lessee warrants that he has full authority to execute this Lease on 
behalf of the corporate Lessee.

          34.  Headings.  Any headings preceding the text of the several
paragraphs and subparagraphs hereof are inserted solely for convenience of
reference and shall not constitute a part of this Lease, nor shall they affect 
its meaning, construction or effect.















          35.  No Recordation.     This Lease may not be recorded by Lessee.

          IN WITNESS WHEREOF, the parties hereto have executed these
presents the day and year first above written.

     Biosonics, Inc.                         
                         

                         By:____________________________
                                   
                         
     185 Commerce Drive Associates, L. P.              
                              

                         By:____________________________