EXHIBIT 5.1


                                              December 6, 2000


Celerity Systems, Inc.
122 Perimeter Park Drive
Knoxville, Tennessee 37922

        Re:  Registration Statement on Form SB-2 (Registration No. 333-48838)

Ladies and Gentlemen:

    You have requested our opinion, as counsel for Celerity Systems, Inc., a
Delaware corporation (the "Company"), in connection with the registration
statement on Form SB-2 (No. 333-48838), as amended (the "Registration
Statement"), filed with the Securities and Exchange Commission under the
Securities Act of 1933, as amended (the "Act").

    The Registration Statement relates to the offering by the Selling
Stockholders, as listed in the Registration Statement, of 8,971,516 shares of
common stock, par value $0.001 per share, of the Company (the "Shares"), of
which (i) 360,000 Shares (the "Warrant Shares") are issuable upon the exercise
of certain warrants (the "Warrants") and (ii) 7 million Shares (the "Debenture
Shares") are issuable upon the conversion of certain convertible debentures (the
"Debentures").

    We have examined such records and documents and made such examinations of
law as we have deemed relevant in connection with this opinion. We have assumed
that there will be no changes in applicable law between the date of this opinion
and the date the Shares proposed to be sold by the Selling Stockholders pursuant
to the Registration Statement are actually sold. In such examination, we have
assumed the genuineness of all signatures, the authenticity of all documents
submitted to us as originals, the conformity to original documents of documents
submitted to us as certified or photostatic copies and the authenticity of the
originals of such latter documents. As to all questions of fact material to this
opinion that have not been independently established, we have relied upon
certificates or comparable documents of officers and representatives of the
Company.

    Based upon such examinations, it is our opinion that (i) the Shares (other
than the Warrant Shares and the Debenture Shares) are validly issued, fully paid
and nonassessable and (ii) when there has been compliance with the Act and the
applicable state securities laws and when the Warrant Shares and the Debenture
Shares have been issued, delivered and paid for upon exercise of the Warrants or
the conversion of the Debentures, as the case may be, in accordance with their
respective terms, the Warrant Shares and the Debenture Shares will be validly
issued, fully paid and nonassessable.

    The opinions herein are limited to the laws of the State of New York, the
General Corporation Law of the State of Delaware, including the applicable
provisions of the Delaware Constitution and reported judicial decisions
interpreting these laws. and the federal laws of the United States, and we
express no opinion as to the effect of the matters covered by this opinion of
the laws of any other jurisdiction.

    We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to our firm under the caption "Legal
Matters" in the Registration Statement. In so doing, we do not admit that we are
in the category of persons whose consent is required under the Section 7 of the
Act or the rules and regulations of the Securities and Exchange Commission
promulgated thereunder.

                                          Very truly yours,