UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549



                                  SCHEDULE 13G

                   Under the Securities Exchange Act of 1934*


                                  I-trax, Inc.
                                  ------------
                                (Name of Issuer)

                         Common Stock, $0.001 par value
                         ------------------------------
                         (Title of Class of Securities)

                                    45069D203
                                    ---------
                                 (CUSIP Number)

                                 March 19, 2004
                                 --------------
             (Date of Event Which Requires Filing of this Statement)

                   Check the appropriate box to designate the
                 rule pursuant to which this Schedule is filed:

                                [ ] Rule 13d-1(b)
                                [X] Rule 13d-1(c)
                                [ ] Rule 13d-1(d)

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).




--------------------                                           -----------------
CUSIP No.  45069D203                   13G                     Page 2 of 5 Pages
--------------------                                           -----------------

--------------------------------------------------------------------------------
1      NAME OF REPORTING PERSON
       S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

       Centre Group Holdings Limited, on behalf of the Centre Group business
       unit
--------------------------------------------------------------------------------
2      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                         (a) [ ]

                                                                         (b) [X]

--------------------------------------------------------------------------------
3      SEC USE ONLY
--------------------------------------------------------------------------------
4      CITIZENSHIP OR PLACE OF ORGANIZATION

       Bermuda
--------------------------------------------------------------------------------
              5    SOLE VOTING POWER

                   -0-
              ------------------------------------------------------------------
  NUMBER OF   6    SHARED VOTING POWER
   SHARES
BENEFICIALLY       2,665,293
  OWNED BY
    EACH      ------------------------------------------------------------------
  REPORTING   7    SOLE DISPOSITIVE POWER
   PERSON
    WITH           -0-

              ------------------------------------------------------------------
              8    SHARED DISPOSITIVE POWER

                   2,665,293
--------------------------------------------------------------------------------
9      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

       2,665,293
--------------------------------------------------------------------------------
10     CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

       [  ]
--------------------------------------------------------------------------------
11     PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

       9.3%
--------------------------------------------------------------------------------
12     TYPE OF REPORTING PERSON*
       CO, HC
--------------------------------------------------------------------------------
                      *SEE INSTRUCTION BEFORE FILLING OUT!


                                       2




This Schedule 13G (this "Schedule 13G") is being filed with respect to the
Common Stock, $0.001 par value of I-trax, Inc.

Item 1(a):          Name of Issuer:
----------          ---------------

     I-trax, Inc., a Delaware corporation (the "Company").

Item 1(b):          Address of Issuer's Principal Executive Offices:
----------          ------------------------------------------------

     One Logan Square, Suite 2615
     130 N. 18th Street
     Philadelphia, Pennsylvania 19103

Item 2(a):          Name of Person Filing:
----------          ----------------------

     Centre Group Holdings Limited, on behalf of the Centre Group business unit.
See Schedule I.

Item 2(b):          Address of Principal Business Office or, if None, Residence:
----------          ------------------------------------------------------------

     Wellesley House
     90 Pitts Bay Road
     Pembroke HM08
     Bermuda

Item 2(c):          Citizenship:
----------          ------------

     Bermuda

Item 2(d):          Title of Class of Securities:
----------          -----------------------------

     Common Stock, $0.001 par value (the "Common Stock")

Item 2(e):          CUSIP Number:
----------          -------------

     45069D203

Item 3:             If this statement is filed pursuant to Rules 13d-1(b) or
-------             --------------------------------------------------------
                    13d-2(b) or (c), check whether the person filing is a:
                    ------------------------------------------------------

     Not applicable.

Item 4:             Ownership:
-------             ----------

     (a)  Amount beneficially owned: See Row 9 on page 2.

     (b)  Percent of class: See Row 11 on page 2.

     (c)  Number of shares as to which the person has:


                                       3




          (i) Sole power to vote or direct the vote: See Row 5 on page 2.

          (ii) Shared power to vote or direct the vote: See Row 6 on page 2.

          (iii) Sole power to dispose or direct the disposition of: See Row 7 on
          page 2.

          (iv) Shared power to dispose or direct the disposition of: See Row 8
          on page 2.

Item 5:             Ownership of Five Percent or Less of a Class:
-------             ---------------------------------------------

     Not applicable.

Item 6:             Ownership of More than Five Percent on Behalf of Another
-------             --------------------------------------------------------
                    Person:
                    -------

     Not applicable.

Item 7:             Identification and Classification of the Subsidiary Which
-------             ---------------------------------------------------------
                    Acquired the Security Being Reported on by the Parent
                    -----------------------------------------------------
                    Holding Company:
                    ----------------

     See Schedule I.

Item 8:             Identification and Classification of Members of the Group:
-------             ----------------------------------------------------------

     Not applicable.

Item 9:             Notice of Dissolution of Group:
-------             -------------------------------

     Not applicable.

Item 10:            Certification:
--------            --------------

     Each Reporting Person hereby makes the following certification:

     By signing below I certify that, to the best of my knowledge and belief,
the securities referred to above were not acquired and are not held for the
purpose of or with the effect of changing or influencing the control of the
issuer of the securities and were not acquired and are not held in connection
with or as a participant in any transaction having that purpose or effect.


                                       4




                                    SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.


Dated: March 26, 2004

                                        CENTRE GROUP HOLDINGS LIMITED

                                        By: /s/ Philip Thorne
                                            ------------------------------
                                          Name:  Philip Thorne
                                          Title: President




                                   Schedule I

     In accordance with Securities and Exchange Commission Release No. 34-39538
(January 12, 1998), this Schedule 13G is being filed by Centre Group Holdings
Limited ("CGHL"), a Bermuda corporation, on behalf of itself and the Centre
Group business unit (the "Reporting Person"). The Reporting Person provides
customized structured insurance and reinsurance products primarily for clients
based in North America and Europe. In 2003, the Reporting Person stopped writing
certain lines of business and those lines are not being renewed. The address of
CGHL's principal business and office is Wellesley House, 90 Pitts Bay Road,
Pembroke HM08, Bermuda.

     The ultimate parent company of CGHL is Zurich Financial Services ("ZFS"), a
Swiss joint stock company. The principal business of ZFS is acting as a holding
company for a global insurance-based financial services group, which includes
certain distinct specialized business units, including the Reporting Person.
ZFS's business address is Mythenquai 2, P.O. Box 8022, Zurich, Switzerland.

     ZFS, for purposes of the federal securities laws, may be deemed ultimately
to control CGHL and the Reporting Person. ZFS, its executive officers and
directors, and its direct and indirect subsidiaries (including all business
units except the Reporting Person), may beneficially own shares of the
securities of the issuer to which this statement relates (the "Shares") and such
Shares are not reported in this statement. In accordance with Securities and
Exchange Commission Release No. 34-39538 (January 12, 1998), and due to the
separate management and independent operation of its business units, ZFS
disclaims beneficial ownership of Shares beneficially owned by the Reporting
Person. The Reporting Person disclaims beneficial ownership of Shares
beneficially owned by ZFS, and any of ZFS's other business units.

     The Shares are directly owned by Centre Reinsurance Limited, a Bermuda
corporation and a direct, wholly owned subsidiary of Centre Solutions (Bermuda)
Limited ("CSBL"), a Bermuda corporation. CSBL is a direct, wholly owned
subsidiary of CGHL.