Exhibit 2.4 to 1997 Form 10-K

                              CERTIFICATE OF MERGER

                                       OF

                                 NEWSUB B, INC.
                            (a Delaware corporation)

                                      INTO

                        SERVICEMASTER LIMITED PARTNERSHIP
                        (a Delaware limited partnership)

            in accordance with Section 17-211 of the Delaware Revised
                         Uniform Limited Partnership Act

                                    * * * * *

         SERVICEMASTER LIMITED PARTNERSHIP, a limited partnership duly organized
and existing under and by virtue of the laws of the State of Delaware,  desiring
to merge NewSub B, a Delaware corporation,  with and into itself pursuant to the
provisions of Section 17-211 of the Delaware Revised Uniform Limited Partnership
Act, DOES HEREBY CERTIFY as follows:

         First:    The name and state of organization of each constituent 
business entity of the merger (the "Merger") are as follows:

         Name                                      State of Organization

         ServiceMaster Limited Partnership                Delaware

         NewSub B, Inc.                                   Delaware

         Second: A Merger and Reorganization  Agreement (the "Merger Agreement")
has  been  approved,  adopted,  certified,  executed  and  acknowledged  by each
constituent  business  entity in  accordance  with  Section  263 of the  General
Corporation  Law of the State of Delaware and in accordance  with Section 17-211
of the Delaware Revised Uniform Limited Partnership Act.

         Third:   The name of the surviving business entity of the Merger is 
ServiceMaster Limited Partnership (the "Surviving Business Entity").

         Fourth:     The merger shall be effective on December 26, 1997 at 11:59
P.M., Eastern Standard Time.


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         Fifth:  Anything  herein or elsewhere to the contrary  notwithstanding,
the  Merger  Agreement  may  be  amended  or  terminated  and  abandoned  by the
constituent  business  entities  at any time  prior to the  date of  filing  the
Certificate of Merger with the Secretary of State of the State of Delaware.

         Sixth:     An executed copy of the Merger Agreement is on file at the 
principal place of business of the Surviving Business Entity, the address of 
which is:  One ServiceMaster Way, Downers Grove, Illinois 60515.

         Seventh:      A copy of the Merger Agreement will be furnished by the 
Surviving Business Entity on request and without cost to any person holding any 
interest in the constituent business entities.

                                 * * * * *

         IN WITNESS WHEREOF,  the undersigned,  for the purposes of effectuating
the Merger of the constituent business entities pursuant to the Delaware Revised
Uniform Limited  Partnership Act, under penalties of perjury does hereby declare
and certify that this is the act and deed of ServiceMaster  Limited  Partnership
and the facts stated herein are true and  accordingly  has hereunto  signed this
Certificate of Merger this 17th day of December 1997.

                                   SERVICEMASTER LIMITED PARTNERSHIP

                                   By: ServiceMaster Management Corporation
                                       (managing general partner)

ATTEST:                            By: /s/ Vernon T. Squires
                                       Its  Sr. Vice President and
                                            General Counsel
/s/ S. D. Baker
Secretary