individuality in handwriting. He maintains that in certain
diseases a person's pulse beats are individual, and that no one
suffering from any such disease can control, even for a brief
space of time, the frequency or peculiar irregularities of his
heart's action, as shown by a chart recording his pulsation. Such
a chart is obtained for medical purposes by means of a
sphygmograph, an instrument fitted to the patient's forearm and
supplied with a needle, which can be so arranged as to record
automatically on a prepared sheet of paper the peculiar force and
frequency of the pulsation. Or the pulsation may be simply
observed in the rise and fall of a liquid in a tube. Dr. Johnson
holds the opinion that a pen in the hand of a writer serves, in a
modified degree, the same end as the needle in the first-named
form of the sphygmograph and that in such a person's handwriting
one can see by projecting the letters, greatly magnified, on a
screen, the scarcely perceptible turns and quivers made in the
lines by the spontaneous action of that person's peculiar
pulsation.

"To prove this, the doctor carried out an experiment at Charing
Cross Hospital. At his request a number of patients suffering
from heart and kidney diseases wrote the Lord's Prayer in their
ordinary handwriting. The different manuscripts were then taken
and examined microscopically. By throwing them, highly magnified,
on a screen, the jerks or involuntary motions due to the
patient's peculiar pulsations were distinctly visible. The
handwriting of persons in normal health, says Dr. Johnson, does
not always show their pulse beats. What one can say, however, is
that when a document, purporting to be written by a certain
person, contains traces of pulse beats and the normal handwriting