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