Almost the only dogmatism that Martin Hewitt permitted himself in regard to his professional methods was one on the matter of accumulative probabilities. Often when I have remarked upon the apparently trivial nature of the clews by which he allowed himself to be guided--sometimes, to all seeming, in the very face of all likelihood--he has replied that two trivialities, pointing in the same direction, became at once, by their mere agreement, no trivialities at all, but enormously important considerations. "If I were in search of a man," he would say, "of whom I knew nothing but that he squinted, bore a birthmark on his right hand, and limped, and I observed a man who answered to the first peculiarity, so far the clue would be trivial, because thousands of men squint. Now, if that man presently moved and exhibited a birthmark on his right hand, the value of that squint and that mark would increase at once a hundred or a thousand fold. Apart they are little; together much. The weight of evidence is not doubled merely; it would be only doubled if half the men who squinted had right-hand birthmarks; whereas the proportion, if it could be ascertained, would be, perhaps, more like one in ten thousand. The two trivialities, pointing in the same direction, become very strong evidence. And, when the man is seen to walk with a limp, that limp (another triviality), re-enforcing the others, brings the matter to the rank of a practical certainty. The Bertillon system of identification--what is it but a summary of trivialities? Thousands of men are of the same height, thousands of the same length of foot, thousands of the same girth of head--thousands correspond in any separate measurement you may name. It is when the measurements are taken _together_ that you have your man identified forever. Just consider how few, if any, of your friends correspond exactly in any two personal peculiarities." Hewitt's dogma received its illustration unexpectedly close at home. The old house wherein my chambers and Hewitt's office were situated contained, besides my own, two or three more bachelors' dens, in addition to the offices on the ground and first and second floors. At the very top of all, at the back, a fat, middle-aged man, named Foggatt, occupied a set of four rooms. It was only after a long residence, by an accidental remark of the housekeeper's, that I learned the man's name, which was not painted on his door or displayed, with all the others, on the wall of the ground-floor porch. Mr. Foggatt appeared to have few friends, but lived in something as nearly approaching luxury as an old bachelor living in chambers can live. An ascending case of champagne was a common phenomenon of the staircase, and I have more than once seen a picture, destined for the top floor, of a sort that went far to awaken green covetousness in the heart of a poor journalist.