Mark Twain once said that whenever he had diverged from custom and principle to utter a truth, the rule had been that the hearer hadn't strength of mind enough to believe it. “Custom is a petrifaction,” he asserted; “nothing but dynamite can dislodge it for a century.” Mr. W. D. Howells has advanced the somewhat fanciful theory that “the ludicrous incongruity of a slave-holding democracy nurtured upon the Declaration of Independence, and the comical spectacle of white labour owning black labour, had something to do in quickening (in Mark Twain) the sense of contrast which is the mountain of humour or is said to be so.” However that may be, Mark Twain was irresistibly driven to the conclusion, Southern born though he was, that slavery was unjust, inhuman, and indefensible. The advanced thinkers in the South had reached this conclusion long before the beginning of the Civil War, and many Southern men had actually devised freedom to their slaves in their wills. The slaves were treated humanely, their material wants were cared for by their owners with a care that can only be called loving, and their spiritual welfare was the frequent concern in particular of the mistress of the house. In his schoolboy days, Mark Twain had no aversion to slavery. He wasn't even aware that there was anything wrong about it. He never heard it condemned by acquaintances or in the local papers. And as for the preachers, they taught that God approved slavery, and cited Biblical passages in support of that view. If the slaves themselves were averse to it, at least they kept discreetly silent on the subject. He seldom saw a slave misused--on the farm, never. But when he was brought face to face with Sandy, the little slave forcibly separated from his family, it made a deep impression upon his consciousness. It was this deplorable evil of the system, this unnatural and inhuman forcible separation of the members of the same family, the one from the other, that convinced him of the injustice of slavery; though this vision, as has been pointed out by Mr. Howells, did not come to him “till after his liberation from neighbourhood in the vaster far West.” Yet it found its way into his books--into Huckleberry Finn, with its recital of Jim's pathetic longing to buy back his wife and children; and in Pudd'nhead Wilson with its moving picture of the poor slave's agony when she suddenly realizes in the way the water is flowing around the snag that she is being “sold down the river.” In Uncle Tom's Cabin, as Professor Phelps has pointed out, “the red--hot indignation of the author largely nullified her evident desire to tell the truth. . . . Mrs. Stowe's astonishing work is not really the history of slavery; it is the history of abolition sentiment. . . . Mark Twain shows us the beautiful side of slavery--for it had a wonderfully beautiful, patriarchal side--and he also shows us the horror of it.” Mark Twain has declared that the only