SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                                  SCHEDULE 13G
                                 (Rule 13d-102)


             INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT
           TO RULES 13d-1(b)(c), AND (d) AND AMENDMENTS THERETO FILED
                            PURSUANT TO RULE 13d-2(b)

                                (Amendment No. 1)


                            Psychemedics Corporation
--------------------------------------------------------------------------------
                                (Name of Issuer)


                         Common Stock, $0.005 par value
--------------------------------------------------------------------------------
                         (Title of Class of Securities)


                                    744375205
--------------------------------------------------------------------------------
                                 (CUSIP Number)


                                December 31, 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)



CUSIP No.  744375205
            ---------------------


1.   NAME OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

     Jeffrey L. Feinberg(1)

2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a) [_]
                                                                        (b) [X]

3.   SEC USE ONLY


4.   CITIZENSHIP OR PLACE OF ORGANIZATION

     United States

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH

5.   SOLE VOTING POWER

     0

6.   SHARED VOTING POWER

     509,900

7.   SOLE DISPOSITIVE POWER

     0

8.   SHARED DISPOSITIVE POWER

     509,900

9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     509,900

10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

                                                                        [_]
----------
(1)  The  securities  reported  herein  are  held by i) a  separately  managed
     account  managed by Jeffrey L. Feinberg and ii) JLF Partners I, L.P., JLF
     Partners  II,  L.P.,  and JLF  Offshore  Fund,  Ltd.,  to which JLF Asset
     Management,  L.L.C.  serves as the management  company and/or  investment
     manager.  Jeffrey  L.  Feinberg  is the  managing  member  of  JLF  Asset
     Management, L.L.C.

11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     9.9%

12.  TYPE OF REPORTING PERSON*

     IN



CUSIP No. 744375205
            ---------------------

1.   NAME OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

     JLF Asset Management, L.L.C.(2)

2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a) [_]
                                                                        (b) [X]

3.   SEC USE ONLY


4.   CITIZENSHIP OR PLACE OF ORGANIZATION

     Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH

5.   SOLE VOTING POWER

     0

6.   SHARED VOTING POWER

     509,900

7.   SOLE DISPOSITIVE POWER

     0

8.   SHARED DISPOSITIVE POWER

     509,900

9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     509,900

10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

                                                                        [_]
----------
(2)  The  securities  reported  herein  are  held by i) a  separately  managed
     account  managed by Jeffrey L. Feinberg and ii) JLF Partners I, L.P., JLF
     Partners  II,  L.P.,  and JLF  Offshore  Fund,  Ltd.,  to which JLF Asset
     Management,  L.L.C.  serves as the management  company and/or  investment
     manager.

11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     9.9%

12.  TYPE OF REPORTING PERSON*

      OO


CUSIP No.  744375205
            ---------------------

Item 1(a).  Name of Issuer:


            Psychemedics Corporation
            --------------------------------------------------------------------

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


            1280 Massachusetts Ave., Suite 200
            Cambridge, MA 02138
            --------------------------------------------------------------------


Item 2(a).  Name of Person Filing:


            Jeffrey L. Feinberg
            JLF Asset Management, L.L.C.

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

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


            Jeffrey L. Feinberg
            c/o JLF Asset Management, L.L.C.
            2775 Via de la Valle, Suite 204
            Del Mar, CA 92014

            JLF Asset Management, L.L.C.
            2775 Via de la Valle, Suite 204
            Del Mar, CA 92014

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

Item 2(c).  Citizenship:


            Jeffrey L. Feinberg - United States
            JLF Asset Management, L.L.C. - United States

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

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


            Common Stock, $0.005 par value
            --------------------------------------------------------------------

Item 2(e).  CUSIP Number:


            744375205
            --------------------------------------------------------------------


Item 3.     If This Statement is Filed Pursuant to Rule 13d-1(b), or 13d-2(b)
            or (c), Check Whether the Person Filing is a:

     (a)  [_] Broker or dealer registered under Section 15 of the Exchange Act.

     (b)  [_] Bank as defined in Section 3(a)(6) of the Exchange Act.

     (c)  [_]  Insurance  company as defined in Section 3(a)(19) of the Exchange
               Act.

     (d)  [_]  Investment  company  registered under Section 8 of the Investment
               Company Act.

     (e)  [_]  An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);

     (f)  [_]  An employee  benefit plan or endowment  fund in  accordance  with
               Rule 13d-1(b)(1)(ii)(F);

     (g)  [_]  A parent  holding  company or control  person in accordance  with
               Rule 13d-1(b)(1)(ii)(G);

     (h)  [_]  A savings  association  as defined in Section 3(b) of the Federal
               Deposit Insurance Act;

     (i)  [_]  A  church  plan  that  is  excluded  from  the  definition  of an
               investment  company  under  Section  3(c)(14)  of the  Investment
               Company Act;

     (j)  [_] Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

Item 4.  Ownership.

     Provide  the  following  information  regarding  the  aggregate  number and
percentage of the class of securities of the issuer identified in Item 1.

     (a)  Amount beneficially owned:

          Jeffrey L. Feinberg: 509,900 shares
          JLF Asset Management, L.L.C.: 509,900 shares
----------------------------------------------------------------------

     (b)  Percent of class:

          Jeffrey L. Feinberg: 9.9%
          JLF Asset Management, L.L.C.: 9.9%
          ----------------------------------------------------------------------

     (c)  Number of shares as to which Jeffrey L. Feinberg has:

          (i)  Sole power to vote or to direct the vote
                                                        0
                                                        ----------------------,

          (ii) Shared power to vote or to direct the vote

                                                        509,900
                                                        ---------------------,

          (iii) Sole power to dispose or to direct 
                the disposition of 
                                                        0
                                                        ---------------------,

          (iv)  Shared power to dispose or to direct 
                the disposition of 
                                                        509,900
                                                        ---------------------.

          Number of shares as to which JLF Asset Management, L.L.C. has:

          (i)  Sole power to vote or to direct the vote
                                                        0
                                                        ----------------------,

          (ii) Shared power to vote or to direct the vote
                                                        509,900
                                                        ---------------------,

          (iii) Sole power to dispose or to direct 
                the disposition of 
                                                        0
                                                        ---------------------,

          (iv)  Shared power to dispose or to direct 
                the disposition of 
                                                        509,900
                                                        ---------------------.

Item 5.  Ownership of Five Percent or Less of a Class.

     If this  statement  is being  filed to report  the fact that as of the date
hereof the reporting  person has ceased to be the beneficial  owner of more than
five percent of the class of securities check the following [ ].

         N/A
         -----------------------------------------------------------------------


Item 6.  Ownership of More Than Five Percent on Behalf of Another Person.

     If any other  person is known to have the right to  receive or the power to
direct the receipt of dividends  from,  or the  proceeds  from the sale of, such
securities,  a statement  to that effect  should be included in response to this
item and, if such interest relates to more than five percent of the class,  such
person  should be  identified.  A listing of the  shareholders  of an investment
company registered under the Investment Company Act of 1940 or the beneficiaries
of employee benefit plan, pension fund or endowment fund is not required.

         N/A
         -----------------------------------------------------------------------


Item 7.  Identification  and Classification of the Subsidiary Which Acquired
         the Security Being Reported on by the Parent Holding Company or Control
         Person.

     If a parent  holding  company  or Control  person has filed this  schedule,
pursuant to Rule  13d-1(b)(1)(ii)(G),  so indicate under Item 3(g) and attach an
exhibit  stating the  identity  and the Item 3  classification  of the  relevant
subsidiary.  If a parent  holding  company  or  control  person  has filed  this
schedule  pursuant to Rule 13d-1(c) or Rule 13d-1(d),  attach an exhibit stating
the identification of the relevant subsidiary.

         N/A
         -----------------------------------------------------------------------


Item 8.  Identification  and  Classification  of Members of the Group.

     If a group has filed this schedule  pursuant to  ss.240.13d-1(b)(1)(ii)(J),
so indicate under Item 3(j) and attach an exhibit  stating the identity and Item
3 classification of each member of the group. If a group has filed this schedule
pursuant to  ss.240.13d-1(c) or  ss.240.13d-1(d),  attach an exhibit stating the
identity of each member of the group.

         N/A
         -----------------------------------------------------------------------


Item 9.  Notice of Dissolution of Group.

     Notice of dissolution of a group may be furnished as an exhibit stating the
date  of  the   dissolution  and  that  all  further  filings  with  respect  to
transactions in the security reported on will be filed, if required,  by members
of the group, in their individual capacity. See Item 5.

          N/A
          ----------------------------------------------------------------------

Item 10.  Certifications.

     Certification  for Rule  13d-1(c):  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.


                                    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.

                                        February 4, 2005
                                        ----------------------------------------
                                                  (Date)

                                        /s/ Jeffrey L. Feinberg(5)
                                        ----------------------------------------
                                        Jeffrey L. Feinberg


                                        JLF Asset Management, L.L.C.

                                        By: /s/ Jeffrey L. Feinberg
                                        ----------------------------------------
                                        Managing Member



Note.  Schedules  filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See Rule 13d-7 for other parties
for whom copies are to be sent.

Attention.  Intentional  misstatements  or omissions of fact constitute  federal
criminal violations (see 18 U.S.C. 1001).

(5) The Reporting Persons disclaim beneficial  ownership except to the extent of
their pecuniary interest therein.


                                                                Exhibit A

                                    AGREEMENT

The  undersigned  agree that this Schedule 13G/A dated February 4, 2005 relating
to the Common Stock, $0.005 par value of Psychemedics Corporation shall be filed
on behalf of the undersigned.

                                                /s/ Jeffrey L. Feinberg
                                                ----------------------------
                                                Jeffrey L. Feinberg

                                                JLF Asset Management, L.L.C.

                                                By: /s/ Jeffrey L. Feinberg
                                                -----------------------------
                                                Name: Jeffrey L. Feinberg
                                                Title: Managing Member


02717.0005 #544274