Porson's Epigram

I made the following Note many years ago:— "The late Professor Porson's own account of his academic visits to the Continent:— "'I went to Frankfort, and got drunk With that most learn'd professor—Brunck: I went to Worts, and got more drunken, With that more learn'd professor Ruhncken.'" But I do not remember where or from whom I got it. Is anything known about it, or its authenticity?