<PAGE>
[NOTE: CERTAIN PORTIONS OF THIS DOCUMENT HAVE BEEN MARKED TO
INDICATE THAT CONFIDENTIALITY HAS BEEN REQUESTED FOR THIS
CONFIDENTIAL INFORMATION.  THE CONFIDENTIAL PORTIONS HAVE BEEN
OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE
COMMISSION.]

                                                     EXHIBIT 10.1



                    LICENSE AND SUPPLY AGREEMENT

     Agreement made as of June 17, 1997 by and between IDEXX
Laboratories, Inc., a Delaware corporation having its principal
place of business at One IDEXX Drive, Westbrook, Maine 04092
("IDEXX"), and Alteon Inc., a Delaware corporation having its
principal place of business at 170 Williams Drive, Ramsey, New
Jersey 07446 ("Alteon").

                            INTRODUCTION

     Alteon possesses certain technology and patents related to
the therapeutic use of pimagedine and certain technology and
patents related to the detection of advanced glycosylation
end-products (AGE's).  IDEXX desires to license from Alteon the
right to use such technology and patents to develop, manufacture
and market therapeutic and diagnostic products for companion
animals, and Alteon desires to license to IDEXX such technology
for such purposes, all on the terms and conditions set forth
herein.

     In consideration of these premises and the mutual covenants
and promises contained in this Agreement, and for other good and
valuable consideration, the receipt and sufficiency of which are
hereby acknowledged, IDEXX and Alteon agree as follows:

                      Article I.  DEFINITIONS

     As used in this Agreement, the following terms, whether used
in the singular or plural, shall have the following meanings: 

     1.1     "Active Ingredients" shall mean pimagedine
(aminoguanidine) and all structurally related compounds.

     1.2     "Affiliate" shall mean, with respect to a party, a
person or entity which controls, is controlled by or is under
common control with, such party.

     1.3     "Confidential Information" shall mean all
information regarding a party's technology, products or business,
which (i) is designated as confidential in writing by the
disclosing party, by letter or by the use of an appropriate stamp
or legend, prior to or at the time any such information is
disclosed by the disclosing party to the other party, or (ii) is
orally or visually disclosed by a party, or is disclosed in
writing without an appropriate letter, stamp or legend, if the
disclosing party, within thirty (30) days after such disclosure,
delivers to the other party a written document or documents
describing the information and referencing the place and date of
such oral, visual or written disclosure and the names of the
persons to whom such disclosure was made.

     1.4     "Dermal Product" shall mean a topical therapeutic
product for use in the treatment of dermatitis in canines to be
developed by IDEXX, based upon or utilizing the Licensed
Technology.

<PAGE>
     1.5     "Diabetes Product" shall mean an oral therapeutic
product for use in the treatment of the complications of diabetes
and/or age-related diseases in canines to be developed by IDEXX,
based upon or utilizing the Licensed Technology.

     1.6     "Diagnostic Products" shall mean such diagnostic
products for use in the Exclusive Area as may be developed by or
on behalf of IDEXX or its Affiliates or sublicensees during the
term of this Agreement, based upon, embodying or utilizing the
Licensed Technology.

     1.7     "Exclusive Area" shall mean all applications for
dogs, cats and horses.

     1.8     "IDEXX Improvements" shall mean improvements and
enhancements to the Licensed Technology which are conceived,
developed or reduced to practice by IDEXX during the term of this
Agreement, and all Patent Rights of IDEXX related thereto.

     1.9     "Licensed Technology" shall mean (i) all technical
information, data, techniques, processes, know-how and trade
secrets throughout the world owned or possessed by, or licensed
to, Alteon (and to which Alteon has the right to grant licenses
or sublicenses) as of the date of this Agreement relating to the
therapeutic use of the Active Ingredients or the detection of
AGE's, (ii) all improvements and enhancements thereto which are
conceived, developed or reduced to practice by, or licensed by
parties other than IDEXX to, Alteon during the term of this
Agreement, and (iii) all Patent Rights of Alteon relating to the
foregoing.

     1.10     "Net Sales" shall mean the gross amount actually
received by IDEXX or its Affiliates on the sale to non-Affiliates
of IDEXX of, or the use of, Therapeutic Products, less (a)
credits or allowances, if any, actually granted, (b) discounts
actually allowed, (c) freight, postage and insurance charges and
additional special packaging charges, if invoiced separately, (d)
customs duties, and (e) excise, sales, value added and similar
taxes imposed upon and paid with respect to such sales (excluding
income taxes).  Net Sales shall not include any amounts received
by IDEXX or any Affiliate on account of the sale of Therapeutic
Products to IDEXX or any other Affiliate.  Net Sales attributable
to a Therapeutic Product which is sold as a "bundle" with one or
more products which are not Therapeutic Products shall be an
amount equal to the list price of the Therapeutic Product
multiplied by a fraction, the numerator of which is the aggregate
sales price for such bundled products and the denominator of
which is the aggregate list price for such bundled products.

     1.11     "Patent Rights" of a party shall mean all patents
and patent applications throughout the world which such party
owns or controls (and to which such party has the right to grant
licenses or sublicenses), including any substitutions,
extensions, reissues, reexaminations, renewals, divisions,
continuations or continuations-in-part.  The patents and patent
applications comprising Patent Rights of Alteon included in
Licensed Technology as of the date of this Agreement are set
forth on Schedule A hereto.


                              - 2 -
<PAGE>
     1.12     "Products" shall mean Diagnostic Products and
Therapeutic Products.

     1.13     "Sublicense Revenue" shall mean all license fees,
royalties or other revenue, including, without limitation,
up-front fees, milestone payments and lump-sum payments, received
by IDEXX or an Affiliate from non-Affiliate sublicensees from the
sublicensing to such non-Affiliates of any Licensed Technology
for use in Therapeutic Products.

     1.14     "Therapeutic Products" shall mean (i) Diabetes
Products, (ii) Dermal Products, and (iii) such other
pharmaceuticals, nutrition supplements or other non-diagnostic
products for use in the Exclusive Area as may be developed by or
on behalf of IDEXX or its Affiliates or sublicensees during the
term of this Agreement, based upon, embodying or utilizing the
Licensed Technology.

     1.15     "Valid Claim" shall mean a claim of any unexpired
United States or foreign patent or patent application which shall
not have been withdrawn, cancelled or disclaimed, nor held
invalid by a court of competent jurisdiction in a final decision
from which an appeal can not be taken.

                   Article II.  LICENSE TERMS

     2.1     License.  Subject to the terms and conditions of
this Agreement, Alteon hereby grants to IDEXX a worldwide,
exclusive license, with full rights to sublicense, to use the
Licensed Technology to develop, have developed, make, have made,
sell, have sold, and use Products for use in the Exclusive Area.

     2.2     Assistance.  From time to time upon the request of
IDEXX, Alteon shall provide to IDEXX, without charge to IDEXX,
(i) at least one copy of all information as may be known or
possessed by Alteon (which Alteon has the right to disclose) and
as may be reasonably necessary for IDEXX to exploit the license
granted in Section 2.1 (including, without limitation, all
documents describing or depicting, and other tangible
manifestations of, the Licensed Technology and such data relating
to the Active Ingredients as IDEXX may reasonably require in
order to prepare, file and obtain any approvals, permits,
licenses or registrations required for the commercial sale of
Products), and (ii) technical assistance in connection with the
transfer to IDEXX of such information and the use thereof by
IDEXX, including such assistance as may be agreed upon by the
parties relating to the development of Products and the
preparation and filing of regulatory submissions.  IDEXX
acknowledges and agrees that nothing in this Agreement shall
obligate Alteon to provide any data or information to IDEXX that
is developed by or with any other licensee of Alteon to the
extent that Alteon is contractually prevented from doing so;
provided, however, that Alteon shall use best efforts to obtain
from each party who in the future becomes a licensee of Alteon
the right to sublicense and provide such data or information to
IDEXX.

     2.3     Improvements.  IDEXX hereby grants to Alteon a
worldwide, exclusive, royalty free, license, with full rights to
sublicense, to use the IDEXX Improvements for


                              - 3- 
<PAGE>
the development, manufacture, sale or use of Active
Ingredient-based products for use in humans or components for
incorporation into Active Ingredient-based products for use in
humans.

     2.4     Facility Inspections.  Alteon shall permit employees
or representatives of IDEXX, during normal business hours and
upon reasonable prior notice, to visit the facilities of Alteon
to observe the manufacture of Active Ingredients, provided that
such visits do not unreasonably disrupt the conduct of the
business undertaken at such facilities.  All such employees or
representatives, while at such facilities, shall comply with all
reasonable rules and regulations established by Alteon.  Alteon
shall permit reasonable inspection of its facilities by
representatives of governmental agencies, if and to the extent
IDEXX believes it necessary or desirable in order to comply with
any statue or regulation or to obtain or maintain any necessary
licenses, permits or approvals.  In the event that Active
Ingredient is manufactured for Alteon by one or more third
parties, Alteon shall use best efforts to require such third
party suppliers to provide to IDEXX inspection rights with
respect to such third parties' facilities equivalent to those set
forth in this Section 2.4.

     2.5  *

* Confidential Treatment Requested         


                              - 4 -
<PAGE>
          *

     2.6     Development Obligation.  IDEXX shall use reasonable
commercial efforts to achieve each of the development milestones
set forth in Section 3.1 within a reasonable period of time after
the date of this Agreement, or as the parties shall mutually
agree.

                 Article III.  FEES AND ROYALTIES

     3.1     License Fees.  In consideration of the licenses
granted herein, IDEXX shall pay to Alteon license fees as
follows:

          (a)     $*, payable within 30 days after the execution
of this Agreement by both parties;

          (b)     $*, payable upon *;

          (c)     $*, payable upon *;

          (d)     $*, payable upon *;

          (e)     $*, payable upon *;

* Confidential Treatment Requested


                              - 5 -
<PAGE>
          (f)     $*, payable upon *; and

          (g)     $*, payable upon *.

Each of the payments required pursuant to Sections 3.1(b) through
3.1(g) shall be paid by IDEXX within 30 days after the
achievement of such milestone.

     3.2     Royalties.

          (a)     Royalty Rate.  IDEXX shall pay to Alteon,
during the applicable term described in Section 3.2 (b), earned
royalties at the rate of *% on all Net Sales of Therapeutic
Products covered by a Valid Claim of any of the Patent Rights
included in Licensed Technology, and *% on all Net Sales of
Therapeutic Products that are not so covered but that are based
upon, embody or use any other Licensed Technology.

          (b)     Payment Period.  The obligation of IDEXX to pay
royalties on Net Sales of Therapeutic Products covered by one or
more Valid Claims shall terminate on a country-by-country basis
concurrently with the expiration or termination of all applicable
patents (if such Valid Claims are patent) or the withdrawal,
cancellation or disclaiming of all applicable patent applications
(if such Valid Claim are patent application) in the country in
the which the Therapeutic Product is manufactured, used or sold. 
The obligation of IDEXX to pay royalties on sales of Therapeutic
Products based upon, embodying or using any other Licensed
Technology shall terminate in all countries on the earlier of (i)
the twentieth anniversary of this Agreement, or (ii) the date on
which such Licensed Technology becomes generally known to the
public.  In no event shall more than one royalty be due for any
Therapeutic Product sold by IDEXX or its Affiliates.  Upon
expiration in accordance with this Section 3.2(b) of the royalty
obligations with respect to all or any portion of the Licensed
Technology, the license granted pursuant to Section 2.1 shall
become, with respect to such Licensed Technology, or portion
thereof, non-exclusive and fully paid.

          (c)     Competitive Products.  In the event that IDEXX
determines that the sales of any Therapeutic Products in any
country are or are likely to be adversely affected by the
introduction by a third party of a pimagedine-based competitive
product, then the parties shall negotiate in good faith with
respect to a reduction in the royalty rate payable with respect
to such Therapeutic Product in such country to reasonably account
for the effects of such competition.

     3.3     Sublicense Fees.  IDEXX shall pay to Alteon *% of
all Sublicense Revenue.  No such amounts shall be payable with
respect to any sublicensing of Licensed Technology to Affiliates
of IDEXX; provided that royalties on Net Sales by such Affiliate
of Therapeutic Products are paid in accordance with the
provisions of Sections 1.10 and 3.2.

* Confidential Treatment Requested


                              - 6 -
<PAGE>
     3.4     Minimum Payments.  IDEXX shall make, with respect to
each successive 12-month period commencing upon the first
commercial sale by IDEXX of a Therapeutic Product, minimum
payments to Alteon (which may either be earned royalties on Net
Sales calculated as set forth in Section 3.2, sublicense fees
under Section 3.3 or voluntary payments in excess of those
calculated and payable under Sections 3.2 and 3.3, or any
combination thereof), in the following amounts:

          (a)     for the first such 12-month period, $*;

          (b)     for the second such 12-month period, $*; and

          (c)     for the third such 12-month period and each
subsequent 12-month period, $*.

The sole consequence of the failure of IDEXX to make the minimum
payments set forth in this Section 3.4 shall be that Alteon may
give notice to IDEXX of its election to amend the license granted
to IDEXX herein so as to make it non-exclusive.  Such license
shall become non-exclusive unless IDEXX shall have made all such
minimum payments within 30 days after such notice; provided,
however, that the right of Alteon to give such notice and to
amend such license shall be suspended if and to the extent that
IDEXX's failure to make the minimum payments has been caused by
the failure of Alteon, for any reason, including on account of an
event of force majeure, to supply Active Ingredient. 

     3.5     Reports and Payments.  IDEXX shall deliver to Alteon
within 60 days after the end of each calendar quarter a written
report showing its computation of royalties and sublicense fees
due under this Agreement for such quarter.  Simultaneously with
the delivery of each such report, IDEXX shall tender payment of
all amounts shown to be due thereon.  During the term of this
Agreement, Alteon shall have the right from time to time (not to
exceed once during each calendar year) to inspect, or have an
agent, accountant or other representative inspect, during normal
business hours, and upon reasonable advance notice (not less than
72 hours), such books, records and other supporting data of IDEXX
as may be necessary to verify IDEXX's computation of payments due
under this Agreement.  In the event Alteon discovers a
discrepancy in one or more report(s) and/or payment(s), then
payment by IDEXX of the shortfall or refund by Alteon of any
overpayment shall be made within 15 (fifteen) days after notice
of such discovery.

       Article IV.  PURCHASE AND SALE OF ACTIVE INGREDIENT

     Alteon shall either: (i) negotiate in good faith with IDEXX
an agreement to supply Active Ingredient to IDEXX at the average
unit price offered to Alteon by * or Alteon's other third party
supplier of Active Ingredient, plus a reasonable handling fee,
and on such other commercially reasonable terms and conditions
(including, without limitation, warranty and product liability
indemnification) as may be mutually agreeable; or (ii) assist
IDEXX, and use best efforts to require its third party

* Confidential Treatment Requested

                              - 7 -
<PAGE>
supplier of Active Ingredient to, negotiate in good faith with
IDEXX an agreement between IDEXX and such third party supplier to
provide for such third party supplier to supply Active Ingredient
to IDEXX at a price and on such other commercially reasonable
terms and conditions (including, without limitation, warranty and
product liability indemnification) as may be mutually agreeable;
or (iii) assist IDEXX, and use best efforts to require any other
licensee of Alteon who is manufacturing Active Ingredient to,
negotiate in good faith an agreement between IDEXX and such
licensee to provide for such licensee to supply Active Ingredient
to IDEXX at a price and on such other commercially reasonable
terms and conditions (including, without limitation, warranty and
product liability indemnification) as may be mutually agreeable.

     In the event that IDEXX has not, despite the use of good
faith efforts, entered into an agreement with Alteon or another
party described in the preceding paragraph for the supply of
Active Ingredient by the earlier of (i) the date on which IDEXX
notifies Alteon that it is ready to commence clinical trials with
respect to a Therapeutic Product (which shall not be earlier than
six months from the date of this Agreement), or (ii) one year
from the date of this Agreement, then IDEXX and Alteon shall
cooperate to obtain another source for the Active Ingredient.  In
such event, IDEXX shall be entitled to deduct, from any payments
then due or in the future coming due under this Agreement, the
amount of such non-recurring expenditures actually and reasonably
incurred by IDEXX in order to establish and qualify a
satisfactory source for the supply of Active Ingredient.  In
connection with the establishment and qualification of a source
for the supply of Active Ingredient, Alteon may provide such
assistance to IDEXX as Alteon deems appropriate in order to
minimize the amount of such expenditures.

              Article V.  INTELLECTUAL PROPERTY RIGHTS

     5.1     Patent Prosecution.  Except as otherwise set forth
in this Article V, Alteon shall have the exclusive right, with
respect to inventions encompassing Licensed Technology, at its
expense, and IDEXX shall have the exclusive right, with respect
to inventions encompassing IDEXX Improvements, at its expense, to
file, prosecute, maintain and enforce patents.  Each party shall
timely notify the other party (but in no event less than 90 days
prior to the expiration of any priority rights period) if it
intends not to seek such patent protection or, after having filed
any patent application, it decides to discontinue prosecution or
maintenance of such applications or patents resulting from such
applications, and thereafter the other party shall have the
right, at its expense but in the name of the party creating the
invention, using counsel reasonably acceptable to such party, to
file, prosecute, maintain and enforce in such country patents
relating to such invention.  Each party shall render such
reasonable assistance as may be necessary to allow the other
party to exploit its right under this Section 5.1, including,
without limitation, using best efforts to have signed all legal
documents appropriate and necessary to file, prosecute, maintain
and enforce patent applications or patents.


                              - 8 -
<PAGE>
     5.2     Infringement.

          (a)     Each party shall promptly report in writing to
the other party during the term of this Agreement any known or
suspected infringement, unauthorized use or misappropriation of
the Licensed Technology or IDEXX Improvements by a third party of
which it becomes aware, and shall provide the other party with
all available evidence supporting said infringement, unauthorized
use or misappropriation.

          (b)     Alteon shall have the initial right, with
respect to Licensed Technology, and IDEXX shall have the initial
right, with respect to IDEXX Improvements, to decide whether or
not to initiate an infringement or other appropriate suit.  If
Alteon or IDEXX, as the case may be, shall decide to file said
suit, such party shall give the other party reasonable advance
notice of filing and shall provide the other party with an
opportunity to make suggestions and comments regarding such suit. 
The party initiating such a suit shall keep the other party
informed of the status of any such suit and, at the request of
the other party, shall provide the other party with copies of all
documents filed in, and all written communications relating to,
such suit.  The party initiating any such suit shall select
counsel who shall be reasonably acceptable to the other party
and, except as provided below, shall pay all expenses of the
suit, including, without limitation, attorneys' fees and court
costs.  The other party, in its sole discretion, may elect, at
any time prior to the commencement of settlement negotiations or
filing of dispositive motions or within 60 days after the receipt
from the initiating party of notice of the commencement of such
litigation, whichever is later, to contribute to the costs
incurred in connection with such litigation in an amount not to
exceed 50% of such costs, whereupon such party shall share in 
any damages, settlement fees or other consideration received as a
result of such litigation pro rata based on its share of costs. 
If necessary, such other party shall join as a party to the suit
but shall be under no obligation to participate except to the
extent that such participation is required as the result of being
a named party to the suit.  The party not initiating such suit
shall offer reasonable assistance to the party initiating such
suit, at no charge except for the reimbursement of reasonable
out-of-pocket expenses.  Such party shall have the right to
participate and be represented in any such suit by its own
counsel at its own expense.  The initiating party shall not
settle any such suit involving rights of the other party without
obtaining the prior written consent of the other party, which
consent shall not be unreasonably withheld.

          (c)     In the event that a party entitled initially to
initiate an infringement action or other appropriate suit does
not initiate such action or suit within 90 days after the date of
notice of infringement, the other party shall have the right, at
its expense, to initiate an infringement or other appropriate
suit on the terms described in Section 5.2(b).  

     5.3     Claimed Infringement.

          (a)     Representations.  Alteon represents and
warrants that (i) it has full power and authority to enter into
this Agreement, to grant all of the rights it hereby grants and
to undertake the commitments it hereby undertakes; (ii) the
execution, delivery and


                              - 9 -
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performance by it of this Agreement in accordance with its terms
do not conflict with, or result in a breach of, any agreement to
which it is a party or by which it or its property is bound; and
(iii) it has received no notice of, and has no knowledge of the
basis for, any claim that the exercise by IDEXX of any right or
license granted under this Agreement shall infringe any patent,
copyright or trade secret of a third party.

          (b)     Indemnification.  Alteon shall defend and
indemnify IDEXX from and against all damages, liabilities, costs
and expenses (including reasonable attorneys' fees and costs)
arising out of any claim that the use of Licensed Technology by
IDEXX as contemplated herein infringes a patent, copyright or
trade secret of a third party, provided that (i) IDEXX shall have
promptly provided Alteon written notice thereof and reasonable
cooperation, information and assistance in connection therewith,
and (ii) Alteon shall have sole control and authority with
respect to the defense, settlement or compromise thereof.

               Article VI.  CONFIDENTIAL INFORMATION

     6.1     Treatment of Confidential Information.  Each party
shall maintain the Confidential Information of the other party in
confidence, and shall not disclose, divulge or otherwise
communicate such Confidential Information to others, or use it
for any purpose, except pursuant to, and in order to carry out,
the terms and objectives of this Agreement.  Each party hereby
agrees to exercise reasonable precautions to prevent the
unauthorized disclosure of such Confidential Information by any
of its directors, officers, employees, consultants,
subcontractors, sublicensees or agents.

     6.2     Release from Restrictions.  The provisions of
Section 6.1 shall not apply to any Confidential Information
disclosed hereunder which:

          (a)     was known or used by the receiving party prior
to its date of disclosure to the receiving party, as evidenced by
the prior written records of the receiving party; or

          (b)     either before or after the date of the
disclosure to the receiving party is lawfully disclosed to the
receiving party by sources other than the disclosing party
rightfully in possession of the Confidential Information; or

          (c)     either before or after the date of the
disclosure to the receiving party becomes published or generally
known to the public through no fault or omission on the part of
the receiving party; or

          (d)     is independently developed by the receiving
party, without reliance upon the Confidential Information of the
disclosing party; or

          (e)     is required to be disclosed by the receiving
party to comply with applicable laws, to defend or prosecute
litigation or to comply with governmental regulations, provided
that the receiving party provides prior written notice of such


                              - 10 -
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disclosure to the other party and takes reasonable and lawful
actions to avoid and/or minimize the degree of such disclosure.

6.3     Term of Obligations.  The obligations of a party under
this Article VI with respect to any Confidential Information of
the other party shall remain in effect until the later of (i)
five years from the date of receipt of the said Confidential
Information or (ii) the termination of this Agreement.

         Article VII.  PRODUCT LIABILITY INDEMNIFICATION

     7.1     Indemnification by IDEXX.  IDEXX shall defend,
indemnify and hold Alteon harmless from and against all claims,
losses, costs, damages, fees or expenses (including the costs and
expenses of attorneys and other professionals) arising out of any
third party claim of injury, damage or death occurring to any
natural person, animal or tangible personal or real property as a
result, directly or indirectly, of the manufacture, use or sale
of Products by IDEXX, its Affiliates or sublicensees pursuant to
this Agreement, except to the extent that such injury, damage or
death was caused by the negligence or willful misconduct of
Alteon.

     7.2     Indemnification by Alteon.  Alteon shall defend,
indemnify and hold IDEXX, its Affiliates and sublicensees
harmless from and against all claims, losses, costs, damages,
fees or expenses (including the costs and expenses of attorneys
and other professionals) arising out of a claim of injury, damage
or death occurring to any natural person, animal or tangible
personal or real property as a result, directly or indirectly, of
the manufacture, use or sale by Alteon, its Affiliates and its
licensees and sublicensees of diagnostic or therapeutic products
containing the Active Ingredient as an active ingredient.

     7.3     Notice.  In the event that a party (the
"Indemnitee") seeks indemnification under this Article VII, the
Indemnitee agrees to: (i) promptly notify the other party (the
"Indemnitor") of any such claim, (ii) permit the Indemnitor to
assume direction and control of the defense and settlement of
such claim (provided, however, that the Indemnitor shall not
settle any such claim without the consent of the Indemnitee,
which consent shall not be unreasonably withheld), and (iii)
cooperate as requested (at the expense of the Indemnitor) in the
defense of the claim. 

               Article VIII.  TERM AND TERMINATION

     8.1     Term.  This Agreement shall remain in effect until
terminated in accordance with the provisions of this Article
VIII.

     8.2     Termination for Breach.  Either party shall be
entitled to terminate this Agreement by written notice to the
other party in the event that the other party shall be in default
of any of its obligations hereunder and shall fail to remedy any
such default within 60 days after notice thereof.


                              - 11 -
<PAGE>
     8.3     Termination by IDEXX.  IDEXX shall have the right to
terminate this Agreement effective on December 31 of any year
(commencing with December 31, 1998), upon not less than 90 days'
prior written notice.

     8.4     Survival of Obligations; Return of Confidential
Information. Upon any termination of this Agreement, each party
shall promptly return to the other party all written Confidential
Information, and all copies thereof, of such other party.  The
termination of this Agreement shall not relieve any party of any
obligations accrued prior to such termination.  Notwithstanding
any termination of this Agreement, the obligations of the parties
with respect to the protection and non-disclosure of Confidential
Information (Article V), intellectual property indemnification
(Section 5.3) and product liability indemnification (Article
VII), as well as any other provisions which by their nature are
intended to survive any such termination, shall survive and
continue to be enforceable. 

                    Article IX.  MISCELLANEOUS

     9.1     Assignment.  Neither party may assign its rights or
obligations hereunder without the prior written consent of the
other party, except that either party may assign its rights and
obligations hereunder without the prior written consent of the
other party in connection with the sale by a party of all or
substantially all of its business or assets relating to the
subject matter of this Agreement.

     9.2     Force Majeure.  Neither party shall be liable for
any delay in or failure to make or take deliveries of any one or
more orders, or portions thereof, due to acts of God, acts of
governments, war, riots, strikes, fire, floods, explosions,
shortages of supplies, destruction or damage to plant or
machinery, or other causes beyond the reasonable control of such
party, provided that such party shall have used its best efforts
to avoid such occurrence and minimize its duration and shall have
given prompt written notice thereof to the other party. 

     9.3     Publicity.  Neither party shall originate any
publicity, news release or other public announcement, written or
oral, relating to this Agreement without the prior written
approval of the other party except as otherwise required by law. 
Such approval shall not be unreasonably withheld. 

     9.4     Governing Law.  This Agreement shall be governed by
and interpreted in accordance with the laws of the State of New
Jersey.

     9.5     Waiver.  The waiver by either party of a breach or a
default of any provision of this Agreement by the other party
shall not be construed as a waiver of any succeeding breach of
the same or any other provision, nor shall any delay or omission
on the part of a party to exercise or avail itself of any right,
power or privilege that it has or may have hereunder operate as a
waiver of any right, power or privilege by such party. 


                              - 12 -
<PAGE>
     9.6     Notices.  Any notice or other communication in
connection with this Agreement must be in writing and delivered
either in person, by recognized overnight carrier, by facsimile
transmission (with telephone confirmation of receipt) or by
certified mail, postage and fees prepaid, return receipt
requested, and addressed as follows:

If to Alteon:     Alteon Inc.
                  170 Williams Drive
                  Ramsey, New Jersey 07446
                  Fax No.:  201-934-0880
                  Attn:  Chairman and Chief Executive Officer

If to IDEXX:      IDEXX Laboratories, Inc.
                  One IDEXX Drive
                  Westbrook, Maine 04092
                  Fax No.:  207-856-0347
                  Attn:  President

or such other address as the addressee shall have specified by
notice hereunder.

     9.7     No Agency.  Nothing herein shall be deemed to
constitute either party as the agent or representative of the
other party, or both parties as joint venturers or partners for
any purpose.  Neither party shall be responsible for the acts or
omissions of the other party, and neither party will have
authority to speak for, represent or obligate the other party in
any way without prior written authority from such other party. 

     9.8     Entire Agreement.  This Agreement and the Schedules
hereto contain the full understanding of the parties with respect
to the subject matter hereof and supersede all prior
understandings and writings relating thereto.  No waiver,
alteration or modification of any of the provisions hereof shall
be binding unless made in writing and signed by both parties.

     9.9     Headings.  The headings contained in this Agreement
are for convenience of reference only and shall not be considered
in construing this Agreement.     

     9.10     Severability.  In the event that any provision of
this Agreement is held by a court of competent jurisdiction to be
unenforceable because it is invalid or in conflict with any law
of any relevant jurisdiction, the validity of the remaining
provisions shall not be affected.  

     9.11     Successors and Assigns.  This Agreement shall be
binding upon and inure to the benefit of the parties hereto and
their successors and permitted assigns.  

     9.12     Counterparts.  This Agreement may be executed in
any number of counterparts, each of which shall be deemed an
original but all of which together shall constitute one and the
same instrument. 


                              - 13 -
<PAGE>
     IN WITNESS WHEREOF, the parties hereto have caused this
Agreement to be executed by their duly authorized officers as of
the date first above written.

                                   IDEXX Laboratories, Inc.



                                   By: /s/ David Shaw
                                       --------------------------
                                   Title: CEO
                                          -----------------------

                                   Alteon Inc.



                                   By: /s/ Kenneth I. Moch
                                       --------------------------
                                   Title: SVP & CFO
                                          -----------------------



                              - 14 -
<PAGE>
                                                       Schedule A

                         Patent Rights
     *

* Confidential Treatment Requested

<PAGE>
     *

Included in this agreement are all foreign counterparts to the
above list of patents.

Notwithstanding the definition of Patent Rights in this Agreement,
the parties acknowledge and agree that the following patent
applications of Alteon shall not be deemed to be included in Patent
Rights of Alteon for purposes of this Agreement:

     *


     The foregoing two patent applications, including any patents
issuing therefrom and any substitutions, extensions, reissues,
reexaminations, renewals, divisions, continuations or
continuations-in-part, and any foreign counterparts to any of the
foregoing, are referred to as the "Excluded Patents."

     Alteon grants IDEXX an option (the "Option") to acquire a
worldwide, exclusive license to the Excluded Patents in the
Exclusive Area, pursuant to the terms and conditions of this
Agreement.  The Option may be exercised at any time commencing on
the date of this Agreement and ending on the earlier of: (i) the
third anniversary of the date of this Agreement, or (ii) the date
that is 60 days after Alteon notifies IDEXX that a third party is
interested in acquiring a license to the Excluded Patents (the
"Option Period").

     IDEXX may exercise the Option at any time during the Option
Period by sending written notice of the exercise of the Option to
Alteon.

* Confidential Treatment Requested
<PAGE>
     Upon exercise of the Option, the Patent Rights of Alteon shall
be expanded to include the Excluded Patents and shall be subject to
all of the terms and conditions contained in this Agreement
applicable thereto, including the payment of any milestones
applicable thereto pursuant to Section 3.1 which have not been paid
prior to the exercise of the Option and the royalties set forth in
Section 3.2.