The Red Thumb Mark | Page 7

powerful and shapely, like the hands of a
skilled craftsman, though faultlessly kept. Thorndyke set on the table a
large condenser such as is used for microscopic work, and taking his
client's hand, brought the bright spot of light to bear on each finger in
succession, examining their tips and the parts around the nails with the
aid of a pocket lens.
"A fine, capable hand, this," said he, regarding the member approvingly,
as he finished his examination, "but I don't perceive any trace of a scar
on either the right or left. Will you go over them, Jervis? The robbery
took place a fortnight ago, so there has been time for a small cut or

scratch to heal and disappear entirely. Still, the matter is worth noting."
He handed me the lens and I scrutinised every part of each hand
without being able to detect the faintest trace of any recent wound.
"There is one other matter that must be attended to before you go," said
Thorndyke, pressing the electric bell-push by his chair. "I will take one
or two prints of the left thumb for my own information."
In response to the summons, Polton made his appearance from some
lair unknown to me, but presumably the laboratory, and, having
received his instructions, retired, and presently returned carrying a box,
which he laid on the table. From this receptacle Thorndyke drew forth a
bright copper plate mounted on a slab of hard wood, a small printer's
roller, a tube of finger-print ink, and a number of cards with very white
and rather glazed surfaces.
"Now, Mr. Hornby," said he, "your hands, I see, are beyond criticism as
to cleanliness, but we will, nevertheless, give the thumb a final polish."
Accordingly he proceeded to brush the bulb of the thumb with a
well-soaked badger-hair nail-brush, and, having rinsed it in water, dried
it with a silk handkerchief, and gave it a final rub on a piece of chamois
leather. The thumb having been thus prepared, he squeezed out a drop
of the thick ink on to the copper plate and spread it out with the roller,
testing the condition of the film from time to time by touching the plate
with the tip of his finger and taking an impression on one of the cards.
When the ink had been rolled out to the requisite thinness, he took
Reuben's hand and pressed the thumb lightly but firmly on to the inked
plate; then, transferring the thumb to one of the cards, which he
directed me to hold steady on the table, he repeated the pressure, when
there was left on the card a beautifully sharp and clear impression of
the bulb of the thumb, the tiny papillary ridges being shown with
microscopic distinctness, and even the mouths of the sweat glands,
which appeared as rows of little white dots on the black lines of the
ridges. This manoeuvre was repeated a dozen times on two of the cards,
each of which thus received six impressions. Thorndyke then took one

or two rolled prints, i.e. prints produced by rolling the thumb first on
the inked slab and then on the card, by which means a much larger
portion of the surface of the thumb was displayed in a single print.
"And now," said Thorndyke, "that we may be furnished with all the
necessary means of comparison, we will take an impression in blood."
The thumb was accordingly cleansed and dried afresh, when
Thorndyke, having pricked his own thumb with a needle, squeezed out
a good-sized drop of blood on to a card.
"There," said he, with a smile, as he spread the drop out with the needle
into a little shallow pool, "it is not every lawyer who is willing to shed
his blood in the interests of his client."
He proceeded to make a dozen prints as before on two cards, writing a
number with his pencil opposite each print as he made it.
"We are now," said he, as he finally cleansed his client's thumb,
"furnished with the material for a preliminary investigation, and if you
will now give me your address, Mr. Hornby, we may consider our
business concluded for the present. I must apologise to you, Mr.
Lawley, for having detained you so long with these experiments."
The lawyer had, in fact, been viewing the proceedings with hardly
concealed impatience, and he now rose with evident relief that they
were at an end.
"I have been highly interested," he said mendaciously, "though I
confess I do not quite fathom your intentions. And, by the way, I
should like to have a few words with you on another matter, if Mr.
Reuben would not mind waiting for me in the square just a few
minutes."
"Not at all," said Reuben,