s may remain
from a casual view of the writing at some time more or less remote;
and besides, one may perceive another in the act of writing and yet
have little or no opportunity of forming any mental conception of it,
even at the time of writing.

In some cases where the courts will permit it the expert witness may
fully explain upon what he bases his opinion but it oftener occurs that
the trial judge will limit the evidence down to the very narrow scope
and the mere relation of such facts as the jury can see. Where a
forgery is well executed the difference in general appearance between
it and the genuine writing of the person whose signature is questioned,
when compared, is very small. The limit put upon expert evidence by the
trial judge takes from the effect of the testimony all the benefit of
an explanation of the facts upon which the opinion is founded.

Juries are generally allowed to examine enlarged photographs of the
writing, and sometimes to see it under the microscope, but even when
so doing what they see unexplained cannot be appreciated intelligently
and unless taken for granted as meaning something which the experience
of the expert who gives the opinion understands, and which they
without such an education, could not be expected to understand that
which the photographs show and the microscope makes visible is just as
likely to be misleading as otherwise.

An expert may testify as to the characteristics of the handwriting in
question; as to whether the writing is natural or feigned, or was or
was not written at the same time, with the same pen and ink, and by
the same person, and as to alterations or erasures therein; and as to
the age of the writing and obscurities therein; the result of his
examination of the writing under a magnifying glass; and to prove in
some cases the standard of comparison.

In the United States a witness may be asked to write on cross-examination,
but not in direct.

Before a paper can be accepted as a standard of comparison it must be
proved to be genuine to the satisfaction of the judge. His decision on
this question is final if supported by proper evidence. In some states
the question of genuineness is for the jury.

A party denying his handwriting may be asked on cross-examination, if
his signature to another instrument is genuine. This is the test which
may be successfully applied to ascertain if the signature is genuine.
A plaintiff, on one occasion, denied most posi