EXHIBIT 3.17

                          CERTIFICATE OF INCORPORATION

                                       OF

                                MDTC Haddon, Inc.

                                   * * * * *

            1. The name of the corporation is

                                MDTC Haddon, Inc.

            2. The address of its registered office in the State of Delaware is
Corporation Trust Center, 1209 Orange Street, in the City of Wilmington, County
of New Castle. The name of its registered agent at such address is The
Corporation Trust Company.

            3. The nature of the business or purposes to be conducted or
promoted is:

            To engage in any lawful act or activity for which corporations may
be organized under the General Corporation Law of Delaware.

            4. The total number of shares of common stock which the corporation
shall have authority to issue is One Hundred (100) and the par value of each of
such shares is Ten Dollars ($10.00) amounting in the aggregate to One Thousand
Dollars ($1,000.00). 



            5. The name and mailing address of each incorporator is as follows:

                  NAME                                MAILING ADDRESS
                  ----                                ---------------

            M. A. Brzoska                       Corporation Trust Center
                                                1209 Orange Street
                                                Wilmington, Delaware 19801

            J. A. Grodzicki                     Corporation Trust Center
                                                1209 Orange Street
                                                Wilmington, Delaware 19801

            L. J. Vitalo                        Corporation Trust Center
                                                1209 Orange Street
                                                Wilmington, Delaware 19801

            6. The corporation is to have perpetual existence.

            7. In furtherance and not in limitation of the powers conferred by
statute, the board of directors is expressly authorized:

            To make, alter or repeal the by-laws of the corporation.

            8. Elections of directors need not be by written ballot unless the
by-laws of the corporation shall so provide.

            Meetings of stockholders may be held within or without the State of
Delaware, as the by-laws may provide. The books of the corporation may be kept
(subject to any provision contained in the statutes) outside the State of
Delaware at such place or places as may be designated from time to time by the
board of directors or in the by-laws of the corporation.



            9. A director of the corporation shall not be personally liable to
the corporation or its stockholders for monetary damages for breach of fiduciary
duty as a director, except for liability (i) for any breach of the director's
duty of loyalty to the corporation or its stockholders, (ii) for acts or
omissions not in good faith or which involve intentional misconduct or a knowing
violation of law, (iii) under Section 174 of the Delaware General Corporation
Law, or (iv) for any transaction from which the director derived any improper
personal benefit. If the Delaware General Corporation Law is hereafter amended
to authorize the further elimination or limitation of the liability of a
director, then the liability of a director of the corporation shall be
eliminated or limited to the fullest extent permitted by the amended Delaware
General Corporation Law.

            Any repeal or modification of the foregoing paragraph by the
stockholders of the corporation shall not adversely affect any right or
protection of a director of the corporation existing at the time of such repeal
or modification.

            10. The corporation reserves the right to amend, alter, change or
repeal any provision contained in this certificate of incorporation, in the
manner now or hereafter prescribed by statute, and all rights conferred upon
stockholders herein are granted subject to this reservation.



            WE, THE UNDERSIGNED, being each of the incorporators hereinbefore
named, for the purpose of forming a corporation pursuant to the General
Corporation Law of the State of Delaware, do make this certificate, hereby
declaring and certifying that this is our act and deed and the facts herein
stated are true, and accordingly have hereunto set our hands this 19th day of
May, 1989.

                                        M. A. Brzoska
                                        ---------------
                                        M. A. Brzoska


                                        J. A. Grodzicki
                                        ---------------
                                        J. A. Grodzicki


                                        L. J. Vitalo
                                        ---------------
                                        L. J. Vitalo