When, on the other hand, he wrote about San Francisco as a correspondent for his paper in the rival community in Nevada, it was, we are told, "with all the fierceness of a flaming indignation long restrained." His impulse, his desire, we see, was not that of the "humorist"; it was that of the satirist; but whether in Nevada or in California he was prohibited, on pain of social extinction, from expressing himself directly regarding the life about him. Satire, in short, had become for him as impossible as murder: he was obliged to remain a humorist. In an old pamphlet about Mark Twain published in the eighties I discover the report of a phrenologist, one "Professor Beall" of Cincinnati, who found the trait of secretiveness very strongly indicated in the diameter of his head just above the ears. Such testimony, I suppose, has no value; but it is surely significant that this gentleman found the same trait exhibited in Mark Twain's "slow, guarded manner of speech." Perhaps we can understand now the famous Mark Twain "drawl," which he had inherited indeed, but which people say he also cultivated. Perhaps we can understand also why it is that half the art of American humor consists in "keeping one's face straight." These humorists! They don't know themselves how much they are concealing; and they would be as surprised as anybody to learn that they are really social revolutionists of a sort who lack the courage to admit it. Mark Twain, once committed to the pursuit of success, was obliged, as I say, to remain a humorist whether he would or no. When he went East to carry on his journalistic career, the publishers of _The Galaxy,_ to which he became a regular contributor, specifically asked him to conduct a "humorous department"; and after the success of "The Innocents Abroad" his publisher Bliss, we find, "especially suggested and emphasized a humorous work--that is to say, a work humorously inclined." We have already seen, in a previous chapter, that whatever was true of the pioneer society on the Pacific Slope was essentially true also of the rest of the American population during the Gilded Age, that the business men of the East were in much the same case as the pioneers of the West. The whole country, as we know, was as thirsty for humor as it was for ice water: Mark Twain's humor fulfilled during its generation a national demand as universal in America as the demand fulfilled in Russia by Dostoievsky in France by Victor Hugo, in England by Dickens. We have at last begun to approach the secret of this interesting fact.