POWER OF ATTORNEY


	Know all by these presents, that the undersigned
hereby constiutes and appoints each of Sirisha
Gummaregula, Michael E. Prevoznik, and Leo C. Farrenkopf,
Jr., signing singly, his true and lawful attorney-in-fact
to:

(1)	execute for and on behalf of the undersigned Forms
3, 4 and 5 in accordance with Section 16(a) of the
Securities Exchange Act of 1934 and the rules thereunder;

(2)	do and perform any and all acts for and on behalf
of the undersigned which may be necessary or desirable to
complete the execution of any such Form 3, 4 or 5 and the
timely filing of such form with the United States
Securities and Exchange Commission and any other
authority; and

(3)	take any other action of any type whatsoever in
connection with the foregoing which, in the opinion of
such attorney-in-fact, may be of benefit to, in the best
interest of, or legally required by, the undersigned, it
being understood that the document executed to this Power
of Attorney shall be in such form and shall contain such
terms and conditions as such attorney-in-fact may approve
in his discretion.

	The undersigned hereby grants to each such
attorney-in-fact full power and authority to do and
perform all and every act and thing whatsoever requisite,
necessary and proper to be done in the exercise of any of
the rights and powers herein granted, as full to all
intents and purposes as the undersigned might or could do
if personally present,with full power of substitute or
substitutes shall lawfully do or cause to be done by
virtue of this power of attorney and the rights and
powers herein granted.  The undersigned acknowledges
that the foregoing attorney-in-fact, in serving
in such capacity at the request of the undersigned, are
not assuming any of the undersigned's responsibilities
to comply with Section 16 of the Securities Exchange Act
of 1934.

	IN WITNESS WHEREOF, the undersigned has caused
this Power of Attorney to be executed as of this
8th day of March, 2004.
		/s/ John C. Baldwin
		Signature
		JOHN C. BALDWIN, M.D.

STATE OF NEW HAMPSHIRE)
	  	      ):  ss.
COUNTY OF GRAFTON     )

	On this 8th day of March, 2004, before me, the
subscriber, personally appeared JOHN BALDWIN, M.D, to me
and known to me to be the same person described in and
who executed the foregoing instrument, and he duly
acknowledged to me that he executed the same.


		/s/ Susan E. Hart
		Notary Public
		My Commission Expires
		March 19, 2008

