Exhibit 7


CONTACTS FOR ENDOGEN:
Owen A. Dempsey, President & CEO                   Michelle L. Linn
Avery W. Catlin, VP Finance & CFO                  or Karen C.K. Drake
 (781) 937-0890                                    Feinstein Kean Partners Inc.
website: http://www.endogen.com                    (617) 577-8110
                                                   website: http://www.fkpi.com

CONTACT FOR PIERCE CHEMICAL COMPANY:
Robb Anderson, President
(815) 968-0747

                                                           FOR IMMEDIATE RELEASE


                PERSTORP AB MAKES OFFER TO ACQUIRE ENDOGEN, INC.

ROCKFORD, ILLINOIS AND WOBURN, MASSACHUSETTS, MAY 27, 1999 - Perstorp AB
subsidiary PerBio Science AB and Endogen, Inc. (Nasdaq: ENDG; BSE: EDG)
announced today that they have executed a definitive merger agreement that
provides for a cash tender offer for all of the outstanding shares of Endogen,
Inc. for a total transaction value of approximately $13.6 million. PerBio
Science AB, which is a leading supplier in several life-science product
segments, consists of the American companies Pierce Chemical Company of
Rockford, Illinois and HyClone Laboratories, Inc. of Logan, Utah and of the
Sweden-based company Atos Medical.

PerBio Science's offer relates to the acquisition of all of the outstanding
shares of Endogen, Inc. for $3.75 per share in cash. The tender offer will be
commenced within five business days. The tender offer will be conditional upon,
among other things, there being validly tendered and not withdrawn at least
two-thirds of the fully-diluted outstanding shares of Endogen, Inc. Upon the
successful completion of the tender offer, a subsidiary of PerBio Science AB
will be merged into Endogen, Inc. and any Endogen, Inc. shares not tendered and
purchased in the tender offer will be converted into the right to receive $3.75
per share in cash.

In connection with the execution of the merger agreement, PerBio Science AB has
entered into an agreement with directors and executive officers of Endogen, Inc.
whereby they have agreed to tender their outstanding shares in the tender offer.

As part of PerBio Science AB, Endogen, Inc. will be closely affiliated with
Pierce Chemical Company. Mr. Robb Anderson, President of Pierce Chemical
Company, said today, "The merger with Endogen, Inc. will strengthen PerBio
Science's position as a world leader providing biotechnology products for the
rapidly growing life science research and drug discovery markets. Endogen's
product portfolio adds to our existing product lines and will enable PerBio
Science to expand it's offerings of high-tech products for immunologists,
molecular biologists and cell biologist."







PerBio Science AB (the former Perstorp Life Science Division) is a wholly owned
subsidiary of Perstorp AB, a global chemistry and materials technology
corporation located in Perstorp, Sweden. In October 1999, PerBio Science AB is
to be spun off to shareholders and listed on the Stockholm Exchange.

Endogen, Inc. is a supplier of specialty reagents, immunoassay test kits and
molecular research products to customers involved in biomedical research, the
biotechnology industry and pharmaceutical drug discovery.


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