Whatever system he adopt, the gambler is always tossing heads or tails against the bank. He has a chance and the bank has a chance; but zero gives the bank odds against him; and, though zero is apparently a very mild tax, since at _rouge-et-noir_ in thirty-six chances the bank has only half a chance more than the player, it is bound to be ruinous in the end. To escape the abruptness of a decision which, if he placed all that he possessed on the red or the black, would end the game at a single stroke, the player divides his stake, so as to be able to defy a large number of chances, hoping that, thanks to a skilfully graduated progression, he will end by lighting on a favourable series in which the gains will exceed the losses. This is the underlying principle of all the systems, which are never anything but more or less ingenious, prudent and complicated martingales. There are not, there never will be any others, in the absence of a miracle which has not yet occurred, of an intuition which foresees what the ball will decide, or of an unknown force which will oblige it to act as a player wishes. 8 I have no intention of reviewing all these systems, which are innumerable and of unequal value: the _paroli_ pure and simple, that artless, violent, doubled stake which leads straight to disaster; the D’Alembert and all its variants; the descending progressions; the differential methods; the _montant belge_; the _parolis intermittents_; the snowball; the _photographie_; the staking of equal amounts on certain groups of figures, which is a Chinese puzzle demanding days of patient observation before it is attacked; and many others which I forget, from the most clear-cut to the most mysterious, which are sold at a high price, to credulous beginners, in sealed envelopes containing what is everybody’s secret and with all or nearly all of which I have become acquainted thanks to the kindness of an erudite player. A detailed account of those most frequently used will be found in D’Albigny’s treatise _Les Martingales modernes_, in Gaston Vessillier’s _Théorie des systèmes géométriques_, in Hulmann’s _Traité des jeux dits de hasard_, in Théo d’Alost’s _Théorie scientifique nouvelle des jeux de la roulette, trente-et-quarante, etc._, and, above all, in the _Revue de Monte Carlo_, which has given a system in every issue since the day of its foundation some fifteen years ago.