characteristics.  These are for the most part unconscious.  He thinks of what he is writing, not how.  In time these peculiarities, which creep gradually into a man’s writing, become fixed habits.  By the time he is, say, twenty-five years old, his writing is settled.  After that it may vary, may grow better or worse, but is certain to retain those distinguishing marks which, in the man himself, we call personality.  This personality remains.  He cannot disguise it, except in a superficial way, any more than he can change his own character.

It follows that no two persons write exactly the same hands.  It is easy to illustrate this.  Suppose, for example, that among 10,000 persons there is one hunchback, one minus his right leg, one with an eye missing, one bereft of a left arm, one with a broken nose.  To find a person with two of these would require, probably, 100,000 people; three of them, 1,000,000; four of them, 100,000,000.  One possessing all of them might not be found in the entire 14,000,000,000 people on earth.  Precisely the same with different handwritings—­the peculiar and distinguishing characteristics of one would no more be present in others than would the personal counterparts of the authors be found in other individuals.

It is more surprising, at first thought, to be told that no person ever signs his name even twice alike.  Of course, theoretically, it cannot be said that it is impossible for a person to write his name twice in exactly the same manner.  A person casting dice might throw double aces a hundred times consecutively.  But who would not act on the practical certainty that the dice were loaded long before the hundredth throw was reached in such a case?  The same reasoning applies to the matter of handwriting with added force, because the chance of two signatures being exactly alike is incomparably less than the chance of the supposed throws of the dice.

Probably many persons will not believe that it is impossible for them to write their own name twice alike.  For them it will be an interesting experiment to repeat their signatures, say, a hundred times, writing them on various occasions and under different circumstances, and then to compare the result.  It is safe to say that they will hardly find two of these which do not present some differences, even to their eyes, and under the examination of a trained observer aided by the microscope, these divergencies stand out tenfold more plainly.

Many cases of forgery hinge on this point, the forger having copied another person’s signature by tracing one in his possession, but such attempts are always more easy to detect than those in which the forger carefully imitates another’s hand.  The latter is the usual procedure.  The forger secures examples of the signature or writing which he desires to imitate.  Then he practices on it, trying to reproduce all its striking peculiarities.  In this way he sometimes arrives at a resemblance so close as to deceive even his victim.  Still there is always present some internal evidence to prove that the writing is not the work of the person to whom it is attributed.  Likewise it will reveal the identity of the person who actully wrote it, if specimens of his natural hand are to be had for comparison.