8-A12B

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                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                               ------------------


                                    FORM 8-A

                FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
                     PURSUANT TO SECTION 12(B) OR (G) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

                               ------------------


                             MALLINCKRODT GROUP INC.
                      (formerly known as IMCERA Group Inc.)
             (Exact name of registrant as specified in its charter)


                 New York                                 36-1263901
 (State of incorporation or organization)   (IRS employer identification number)


7733 Forsyth Boulevard, St. Louis, Missouri                 63105
 (Address of principal executive offices)                 (Zip Code)


                     SECURITIES TO BE REGISTERED PURSUANT TO
                            SECTION 12(b) OF THE ACT



     Title of each class                    Name of each exchange on which
      to be so registered                    each class is to be registered

  6% Notes due October 15, 2003            New York Stock Exchange, Incorporated
 7% Debentures due December 15, 2013       New York Stock Exchange, Incorporated

                     SECURITIES TO BE REGISTERED PURSUANT TO
                            SECTION 12(G) OF THE ACT

                                      None



Item 1.   Description of Registrant's Securities to be Registered.

          On April 27, 1992, Registration Statement No. 33-47081 on Form S-3 of
Mallinckrodt Group Inc., formerly known as IMCERA Group Inc. (the "Company"), a
New York corporation, relating to $250,000,000 of Debt Securities, was declared
effective.

          (a) $100,000,000 AGGREGATE PRINCIPAL AMOUNT OF 6% NOTES DUE
OCTOBER 15, 2003 (THE "NOTES") OF THE COMPANY.

          The Company issued a Prospectus, dated October 12, 1993, as
supplemented by Prospectus Supplement dated October 19, 1993, pursuant to the
aforementioned Registration Statement, relating to the Notes.  The information
set forth under the caption "Description of the Securities" in such Prospectus
and under the caption "Description of the Notes" in such Prospectus Supplement
is incorporated herein by reference.

          (b) $100,000,000 AGGREGATE PRINCIPAL AMOUNT OF 7% DEBENTURES DUE
DECEMBER 15, 2013 (THE "DEBENTURES") OF THE COMPANY.

          The Company issued a Prospectus, dated December 1, 1993, as
supplemented by Prospectus Supplement dated December 8, 1993, pursuant to the
aforementioned Registration Statement, relating to the Debentures.  The
information set forth under the caption "Description of the Securities" in such
Prospectus and under the caption "Description of the Debentures" in such
Prospectus Supplement is incorporated herein by reference.



Item 2.   Exhibits


Exhibit
Number

4.1            Form of Indenture dated as of March 15, 1985 between the Company
               and Morgan Guaranty Trust Company of New York, as Trustee,
               including Form of Securities (incorporated by reference to
               Registration Statement No. 2-96566)



4.2            Form of First Supplemental Indenture dated as of April 1, 1992,
               to Indenture dated March 15, 1985 (incorporated by reference to
               Registration Statement No. 33-47081)

4.3            Specimen 6% Note due October 15, 2003

4.4            Specimen 7% Debenture due December 15, 2013

                                       -2-



                                    Signature


          Pursuant to the requirements of Section 12 of the Securities Exchange
Act of 1934, the registrant has duly caused this Registration Statement to be
signed on its behalf by the undersigned, thereunto duly authorized.

                                           MALLINCKRODT GROUP INC.



                                           By /s/ WILLIAM B. STONE
                                             --------------------------
                                             Name:  William B. Stone
                                             Title: Vice-President and
                                                    Controller

Date:   May 6, 1994

                                       -3-



                                  EXHIBIT INDEX

                                                                    Sequentially
Exhibit                                                               Numbered
Number         Description                                              Page
- -------        -----------                                          ------------

4.1            Form of Indenture dated as of March 15, 1985
               between the Company and Morgan Guaranty Trust
               Company of New York, as Trustee, including Form of
               Securities (incorporated by reference to
               Registration Statement No. 2-96566)

4.2            Form of First Supplemental Indenture dated as of
               April 1, 1992, to Indenture dated March 15, 1985
               (incorporated by reference to Registration
               Statement No. 33-47081)

4.3            Specimen 6% Note due October 15, 2003

4.4            Specimen 7% Debenture due December 15, 2013

                                       -4-

EX-4.3

UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY (THE "DEPOSITARY") (55 WATER STREET, NEW YORK, NEW
YORK) TO THE ISSUER OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAY-
MENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH
OTHER NAME AS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST
COMPANY AND ANY PAYMENT IS MADE TO CEDE & CO., ANY TRANSFER, PLEDGE OR OTHER USE
HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL SINCE THE REGIS-
TERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

                                IMCERA GROUP INC.

                          6% Notes due October 15, 2003

                                                                 CUSIP 452454AA9
No 1                                                                $100,000,000

     IMCERA GROUP INC., a corporation organized and existing under the laws of
the State of New York (hereinafter called the "Company", which term shall
include any successor corporation), for value received, hereby promises to pay
to CEDE & CO., or registered assigns, the principal sum of One Hundred Million
Dollars ($100,000,000.00) on October 15, 2003, and to pay interest thereon from
October 15, 1993 or from the most recent Interest Payment Date to which interest
has been paid or duly provided for, semi-annually on April 15 and October 15 in
each year, commencing April 15, 1994, at the rate of 6% per annum, until the
principal hereof is paid or made available for payment.  The interest so
payable, and punctually paid or duly provided for, on any Interest Payment Date
will, as provided in the Indenture hereinafter referred to, be paid to the
Person in whose name this Debt Security (or one or more Predecessor Debt
Securities) is registered at the close of business on the Regular Record Date
for such interest, which shall be the April 1 or October 1 (whether or not a
Business Day), as the case may be, next preceding such Interest Payment Date.
Any such interest not so punctually paid or duly provided for will forthwith
cease to be payable to the Holder on such Regular Record Date and may either be
paid to the person in whose name this Debt Security (or one or more Predecessor
Debt Securities) is registered at the close of business on a Special Record Date
for the payment of such Defaulted Interest to be fixed by the Trustee, notice
whereof shall be given to Holders of Debt Securities of this series not less
than ten days prior to such Special Record Date, or be paid at any time in any
other lawful manner not inconsistent with the requirements of any securities
exchange on which the Debt Securities of this series may be listed, and upon
such notice as may be required by such exchange, as more fully provided in the
Indenture.

     Payment of the principal of and interest on this Security will be made at
the office or agency of the Company maintained for that purpose in the Borough
of Manhattan, The City of New York, in such coin or currency of the United
States of America as at the time of payment is legal tender for payment of
public and private debts; PROVIDED, HOWEVER, that at the option of the Company
payment of interest may be made by check mailed to the address of the Person
entitled thereto as such address shall appear in the Debt Security Register.

     Reference is hereby made to the further provisions of this Debt Security
set forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

     Unless the certificate of authentication hereon has been executed by the
Trustee referred to on the reverse hereof by manual signature, this Debt
Security shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.

     IN WITNESS WHEREOF, the Company has caused this Instrument to be duly
executed under its corporate seal.

Dated:    October 15, 1993              IMCERA GROUP INC.


                                        By_______________________
                                         Vice President and Treasurer

Attest:

________________________
  Assistant Secretary

     This is one of the Debt Securities of the series designated herein issued
under the within-mentioned Indenture.

                                      MORGAN GUARANTY TRUST COMPANY OF NEW YORK,
                                                                as Trustee

                                      By___________________________
                                        Authorized Officer



                                IMCERA GROUP INC.

                          6% Notes due October 15, 2003


     This Debt Security is one of a duly authorized issue of securities of the
Company (herein called the "Debt Securities"), issued and to be issued in one or
more series under an Indenture, dated as of March 15, 1985, as supplemented by a
First Supplemental Indenture dated as of April 1, 1992 (as so supplemented,
herein called the "Indenture"), between the Company and Morgan Guaranty Trust
Company of New York, a New York banking corporation, as trustee (herein called
the "Trustee", which term includes any successor trustee under the Indenture),
to which Indenture and all indentures supplemental thereto reference is hereby
made for a statement of the respective rights, limitations of rights, duties and
immunities thereunder of the Company, the Trustee and the Holders of the Debt
Securities and of the terms upon which the Debt Securities are, and are to be,
authenticated and delivered.  This Debt Security is one of the series designated
on the face hereof, limited in aggregate principal amount to $100,000,000.

     The Debt Securities of this series are not subject to redemption prior to
maturity.

     If an Event of Default with respect to Debt Securities of this series shall
occur and be continuing, the principal of the Debt Securities of this series may
be declared due and payable in the manner and with the effect provided in the
Indenture.

     The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Company and the rights of the Holders of the Debt Securities of each series to
be affected under the Indenture at any time by the Company and the Trustee with
the consent of the Holders of greater than 50% in aggregate principal amount of
the Debt Securities at the time Outstanding of each series to be affected.  The
Indenture also contains provisions permitting the Holders of a majority in
aggregate principal amount of the Debt Securities of each series at the time
Outstanding, on behalf of the Holders of all Debt Securities of such series, to
waive compliance by the Company with certain provisions of the Indenture and
certain past defaults under the Indenture and their consequences.  Any such
consent or waiver by the Holder of this Debt Security shall be conclusive and
binding upon such Holder and upon all future Holders of this Debt Security and
of any Debt Security issued upon the registration of transfer hereof or in
exchange herefor or in lieu hereof, whether or not notation of such consent or
waiver is made upon this Debt Security.

     Except in the event the Company deposits money or government securities as
provided in Section 13.01 of the Indenture, the obligation of the Company to pay
the principal of and interest on this Debt Security at the times, place and
rate, and in the coin or currency herein provided is absolute and unconditional.

     As provided in the Indenture and subject to certain limitations therein and
herein set forth, the transfer of this Debt Security is registrable in the Debt
Security Register, upon surrender of this Debt Security for registration of
transfer at the office or agency of the Company in any place where the principal
of and interest on this Debt Security are payable, duly endorsed by, or
accompanied by a written instrument of transfer in form satisfactory to the
Company and the Debt Security registrar duly executed by, the Holder hereof or
his attorney duly authorized in writing, and thereupon one or more new Debt
Securities of this series, of authorized denominations and for the same
aggregate principal amount, will be issued to the designated transferee or
transferees.

     The Debt Securities of this series are issuable only in registered form
without coupons in denominations of $1,000 and any integral multiple thereof.
As provided in the Indenture and subject to certain limitations therein and
herein set forth, Debt Securities of this series are exchangeable for a like
aggregate principal amount of Debt Securities of this series of a different
authorized denomination, as requested by the Holder surrendering the same.

     Notwithstanding anything herein to the contrary, so long as the Depositary
or its nominee is the registered owner of this Note or any Note issued in
exchange herefor, the Depositary or its nominee, as the case may be, will be
considered the sole owner or holder of the Notes represented hereby for all
purposes under the Indenture.  Unless and until either (a) the Depositary is at
any time unwilling or unable to continue as depositary and a successor
depositary is not appointed by the Company within 90 days, or (b) the Company
elects in its sole discretion not to have the Notes held by the Depositary,
owners of beneficial interests in this Note will not be entitled to have Notes
represented hereby registered in their names, will not receive or be entitled to
receive physical delivery of such Notes in definitive form, and will not be
considered the owners or holders thereof under the Indenture.

     No service charge shall be made for any such registration of transfer or
exchange, but the Company may require payment of a sum sufficient to cover any
tax or other governmental charge payable in connection therewith.

     Prior to due presentment of this Debt Security for registration of
transfer, the Company, the Trustee and any agent of the Company or the Trustee
may treat the Person in whose name this Debt Security is registered as the owner
hereof for all purposes, whether or not this Debt Security be overdue, and
neither the Company, the Trustee nor any such agent shall be affected by notice
to the contrary.

     All terms used in this Debt Security which are defined in the Indenture
shall have the meanings assigned to them in the Indenture.

                                       -2-

EX-4.4

UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY (THE "DEPOSITARY") (55 WATER STREET, NEW YORK, NEW
YORK) TO THE ISSUER OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAY-
MENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH
OTHER NAME AS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST
COMPANY AND ANY PAYMENT IS MADE TO CEDE & CO., ANY TRANSFER, PLEDGE OR OTHER USE
HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL SINCE THE REGIS-
TERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

                                IMCERA GROUP INC.

                       7% Debentures due December 15, 2013

                                                                 CUSIP 452454AB7
No 1                                                                $100,000,000

     IMCERA GROUP INC., a corporation organized and existing under the laws of
the State of New York (hereinafter called the "Company", which term shall
include any successor corporation), for value received, hereby promises to pay
to CEDE & CO., or registered assigns, the principal sum of One Hundred Million
Dollars ($100,000,000.00) on December 15, 2013, and to pay interest thereon from
December 15, 1993 or from the most recent Interest Payment Date to which
interest has been paid or duly provided for, semi-annually on June 15 and
December 15 in each year, commencing June 15, 1994, at the rate of 7% per annum,
until the principal hereof is paid or made available for payment.  The interest
so payable, and punctually paid or duly provided for, on any Interest Payment
Date will, as provided in the Indenture hereinafter referred to, be paid to the
Person in whose name this Debt Security (or one or more Predecessor Debt
Securities) is registered at the close of business on the Regular Record Date
for such interest, which shall be the June 1 or December 1 (whether or not a
Business Day), as the case may be, next preceding such Interest Payment Date.
Any such interest not so punctually paid or duly provided for will forthwith
cease to be payable to the Holder on such Regular Record Date and may either be
paid to the person in whose name this Debt Security (or one or more Predecessor
Debt Securities) is registered at the close of business on a Special Record Date
for the payment of such Defaulted Interest to be fixed by the Trustee, notice
whereof shall be given to Holders of Debt Securities of this series not less
than ten days prior to such Special Record Date, or be paid at any time in any
other lawful manner not inconsistent with the requirements of any securities
exchange on which the Debt Securities of this series may be listed, and upon
such notice as may be required by such exchange, as more fully provided in the
Indenture.

     Payment of the principal of and interest on this Security will be made at
the office or agency of the Company maintained for that purpose in the Borough
of Manhattan, The City of New York, in such coin or currency of the United
States of America as at the time of payment is legal tender for payment of
public and private debts; PROVIDED, HOWEVER, that at the option of the Company
payment of interest may be made by check mailed to the address of the Person
entitled thereto as such address shall appear in the Debt Security Register.

     Reference is hereby made to the further provisions of this Debt Security
set forth on the reverse hereof, which further provisions shall for all purposes
have the same effect as if set forth at this place.

     Unless the certificate of authentication hereon has been executed by the
Trustee referred to on the reverse hereof by manual signature, this Debt
Security shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.

     IN WITNESS WHEREOF, the Company has caused this Instrument to be duly
executed under its corporate seal.

Dated:    December 15, 1993             IMCERA GROUP INC.


                                        By_______________________
                                         Vice President and Treasurer

Attest:

________________________
      Secretary

     This is one of the Debt Securities of the series designated herein issued
under the within-mentioned Indenture.

                                      MORGAN GUARANTY TRUST COMPANY OF NEW YORK,
                                                                as Trustee

                                      By___________________________
                                        Authorized Officer



                                IMCERA GROUP INC.

                       7% Debentures due December 15, 2013


     This Debt Security is one of a duly authorized issue of securities of the
Company (herein called the "Debt Securities"), issued and to be issued in one or
more series under an Indenture, dated as of March 15, 1985, as supplemented by a
First Supplemental Indenture dated as of April 1, 1992 (as so supplemented,
herein called the "Indenture"), between the Company and Morgan Guaranty Trust
Company of New York, a New York banking corporation, as trustee (herein called
the "Trustee", which term includes any successor trustee under the Indenture),
to which Indenture and all indentures supplemental thereto reference is hereby
made for a statement of the respective rights, limitations of rights, duties and
immunities thereunder of the Company, the Trustee and the Holders of the Debt
Securities and of the terms upon which the Debt Securities are, and are to be,
authenticated and delivered.  This Debt Security is one of the series designated
on the face hereof, limited in aggregate principal amount to $100,000,000.

     The Debt Securities of this series are not subject to redemption prior to
maturity.

     If an Event of Default with respect to Debt Securities of this series shall
occur and be continuing, the principal of the Debt Securities of this series may
be declared due and payable in the manner and with the effect provided in the
Indenture.

     The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Company and the rights of the Holders of the Debt Securities of each series to
be affected under the Indenture at any time by the Company and the Trustee with
the consent of the Holders of greater than 50% in aggregate principal amount of
the Debt Securities at the time Outstanding of each series to be affected.  The
Indenture also contains provisions permitting the Holders of a majority in
aggregate principal amount of the Debt Securities of each series at the time
Outstanding, on behalf of the Holders of all Debt Securities of such series, to
waive compliance by the Company with certain provisions of the Indenture and
certain past defaults under the Indenture and their consequences.  Any such
consent or waiver by the Holder of this Debt Security shall be conclusive and
binding upon such Holder and upon all future Holders of this Debt Security and
of any Debt Security issued upon the registration of transfer hereof or in
exchange herefor or in lieu hereof, whether or not notation of such consent or
waiver is made upon this Debt Security.

     Except in the event the Company deposits money or government securities as
provided in Section 13.01 of the Indenture, the obligation of the Company to pay
the principal of and interest on this Debt Security at the times, place and
rate, and in the coin or currency herein provided is absolute and unconditional.

     As provided in the Indenture and subject to certain limitations therein and
herein set forth, the transfer of this Debt Security is registrable in the Debt
Security Register, upon surrender of this Debt Security for registration of
transfer at the office or agency of the Company in any place where the principal
of and interest on this Debt Security are payable, duly endorsed by, or
accompanied by a written instrument of transfer in form satisfactory to the
Company and the Debt Security registrar duly executed by, the Holder hereof or
his attorney duly authorized in writing, and thereupon one or more new Debt
Securities of this series, of authorized denominations and for the same
aggregate principal amount, will be issued to the designated transferee or
transferees.

     The Debt Securities of this series are issuable only in registered form
without coupons in denominations of $1,000 and any integral multiple thereof.
As provided in the Indenture and subject to certain limitations therein and
herein set forth, Debt Securities of this series are exchangeable for a like
aggregate principal amount of Debt Securities of this series of a different
authorized denomination, as requested by the Holder surrendering the same.

     Notwithstanding anything herein to the contrary, so long as the Depositary
or its nominee is the registered owner of this Debenture or any Debenture issued
in exchange herefor, the Depositary or its nominee, as the case may be, will be
considered the sole owner or holder of the Debentures represented hereby for all
purposes under the Indenture.  Unless and until either (a) the Depositary is at
any time unwilling or unable to continue as depositary and a successor
depositary is not appointed by the Company within 90 days, or (b) the Company
elects in its sole discretion not to have the Debentures held by the Depositary,
owners of beneficial interests in this Debenture will not be entitled to have
Debentures represented hereby registered in their names, will not receive or be
entitled to receive physical delivery of such Debentures in definitive form, and
will not be considered the owners or holders thereof under the Indenture.

     No service charge shall be made for any such registration of transfer or
exchange, but the Company may require payment of a sum sufficient to cover any
tax or other governmental charge payable in connection therewith.

     Prior to due presentment of this Debt Security for registration of
transfer, the Company, the Trustee and any agent of the Company or the Trustee
may treat the Person in whose name this Debt Security is registered as the owner
hereof for all purposes, whether or not this Debt Security be overdue, and
neither the Company, the Trustee nor any such agent shall be affected by notice
to the contrary.

     All terms used in this Debt Security which are defined in the Indenture
shall have the meanings assigned to them in the Indenture.

                                       -2-