W-e-e-e-e-e-e-ll, that's more a clue than a source, but a good possibility, deserving of a beer if not the hard stuff. Henderson's text reads "Certain passages in his books on the subject of slavery, as the historian Lecky has declared, are the truest things that have ever been expressed on the subject which vexed a continent and plunged a nation in bloody, fratricidal strife." Henderson himself (not Lecky, as I'd implied --sorry) then goes on to cite HF and LonM as having particularly vivid examples of what he's talking about. I may be reading him wrong, but the way Henderson puts it seems to indicate he assumes his readers will be familiar with Lecky's opinion, or at least that it had been stated in public or in print. I was initially confident the source was buried in H's appendix (an excellent bibliography by 1910 standards), but Lecky's name does not appear under any of those entries. Henderson had interviewed Twain at length while preparing this book, and I've wondered if perhaps Twain showed H some letter to T from Lecky (none in Machlis), or even if H perhaps discussed with Twain his (T's) readings of Lecky and then later on garbled his (H's) notes of that conversation. Kevin Mac Donnell Austin TX