"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