source for one-liner

[Laurence Horn]

Over on the forensic linguistics list in a thread on plagiarism,
someone brought up a quote attributed to Samuel Johnson:  commenting
on a book of a mediocre author that "the work was good and original.
Unfortunately, he noted, what is good is not original and what is
original is not good."  I wondered if this conceit was original with
Dr. Johnson, since I've long been familiar with the similar French
mot juste, "Ce qui est bon n'est pas neuf; ce qui est neuf n'est pas
bon"  (or possibly "Tout ce qui est bon...").  But when asked, I
couldn't provide an attribution, and neither google nor Bartlett's
was any help.  Anyone know where this came from (first)?  Fred, do
you have this one in either the Dr. J or the French version?

larry