Exhibit
        4.27.1

      Generex
        Biotechnology Corporation

      33
        Harbour Square, Suite 202

      Toronto,
        Ontario

      Canada
        M5J 2G2

      


      


      


      


      


      July
        22,
        2005

      


      Cranshire
        Capital, L.P.

      666
        Dundee Road, Suite 1901

      Northbrook,
        Illinois

      USA
        60062

      


      


      Dear
        Sirs:

      


      Re: Generex
        Biotechnology Corporation

      -
        Promissory Note & Agreement dated March 28, 2005

      


      We
        make
        reference to the Promissory Note & Agreement (the “Note”)
        dated
        March 28, 2005 in the principal amount of Five Hundred Thousand Dollars
        ($500,000) executed and delivered by Generex Biotechnology Corporation (the
        “Borrower”)
        in
        favour of Cranshire Capital, L.P. (the “Holder”),
        as
        the same was amended by letter agreement dated June 7, 2005.

      


      We
        hereby
        confirm the mutual agreement of the Borrower and the Holder to further amend
        the
        terms of the Note by extending the interest payment date and the maturity
        date
        thereof from July 22, 2005 to September
        20, 2005.

      


      We
        hereby
        further confirm that, in consideration for the Holder’s agreement to the
        foregoing amendment of the Note, the Borrower will forthwith issue to the
        Holder
        a warrant (the “Amendment
        Warrant”)
        to
        purchase an aggregate of 1, 219,512 shares of the Borrower’s common stock (the
“Amendment
        Warrant Shares”)
        at a
        per-share price of Eighty Two Cents ($0.82), such warrant to expire on July
        22,
        2010.

      


      From
        and
        after the date hereof, the term “Warrant”
        in the
        Note will be deemed to include the Amendment Warrant, and the term “Warrant
        Shares”
        in the
        Note will be deemed to include the Amendment Warrant Shares.

      


      continued............................................................................................................


      
        
          
             

          

           

        

        
           

          
            

          

        

        
           

        

      


      


      In
        all
        other respects, the Note will remain in full force and effect and
        unamended.

      


      Yours
        truly,

      


      Generex
        Biotechnology Corporation

      


      


      /s/
        Rose
        C. Perri

      ____________________________________

      Rose
        C.
        Perri

      Chief
        Financial Officer

      


      AGREED.

      


      Cranshire
        Capital, L.P.

      


      /s/
        Lawrence A. Prosser

      ____________________________________

      Lawrence
        A. Prosser

      Chief
        Financial Officer - Downsview Capital, Inc.

      The
        General Partner

       

      
 

      
        
           

        

        
          2