ow the proper qualifications for giving
expert testimony.

The constant professional observation of handwriting in any line of
financial or commercial business tends to confer expert skill. It
should be said here, however, that the average bank cashier or teller
bases his opinions and his identifications generally upon the
pictorial effect without recourse to those minuter and more delicate
points upon which the skilled expert rightly places the greatest
reliance. Such testimony can not be compared for accuracy or value
with that of the scientific investigator of handwriting. It follows,
then, that one who is endowed with more than ordinary acuteness of
observation, and has had an experience so varied and extensive as to
cover most of these lines, is likely to be best fitted for critical
and reliable expert work.

In a word, the trained expert eye, even on so slight a thing as a
simple straight line, will detect certain peculiarities of motion, of
force, of pressure, of tool-mark, etc., that in normal circumstances
the result will stand for its author just as his photograph stands for
him. Now, this being undoubtedly true within certain limitations, how
more than incontestable must be the proposition to any rational man
that if, instead of a simple undeviating pen-stroke, lines that run to
curves and angles and slants, and shades and loops and ticks, and
enter into all sorts of combinations, such as any specimen of
handwriting must, however simple, bear inherent evidences of
authorship that yield their secrets to the expert examiner as the
hieroglyphics on an Egyptian monument do to a properly educated
antiquarian.

The propriety of admitting the evidence of handwriting experts in
investigating questions of forgery is now recognized by statute in
most states. Common sense dictates that in all investigations
requiring special skill, or when the common intelligence supposed to
be possessed by the jury is not fully adequate to the occasion, we
should accept the assistance of persons whose studies or occupations
have given them a large and special experience on the subject. Thus
such men of experience or experts are admitted to testify that work of
a given description is or is not executed with ordinary skill; what is
the ordinary price of a described article; whether described medical
treatment or other practice was conducted with ordinary skill in a
specific case; which of two colliding vessels, their respective
move