careful examination of the
hall. Besides, it's not in a very prominent place, as you see."

"No, no, of course not. I suppose there is no doubt that the mark was
there yesterday?"

Lestrade looked at Holmes as if he thought he was going out of his mind.
I confess that I was myself surprised both at his hilarious manner and
at his rather wild observation.

"I don't know whether you think that McFarlane came out of gaol in the
dead of the night in order to strengthen the evidence against himself,"
said Lestrade. "I leave it to any expert in the world whether that is
not the mark of his thumb."

"It is unquestionably the mark of his thumb."

"There, that's enough," said Lestrade. "I am a practical man, Mr.
Holmes, and when I have got my evidence I come to my conclusions. If
you have anything to say you will find me writing my report in the
sitting-room."

Holmes had recovered his equanimity, though I still seemed to detect
gleams of amusement in his expression.

"Dear me, this is a very sad development, Watson, is it not?" said he.
"And yet there are singular points about it which hold out some hopes
for our client."

"I am delighted to hear it," said I, heartily. "I was afraid it was all
up with him."

"I would hardly go so far as to say that, my dear Watson. The fact is
that there is one really serious flaw in this evidence to which our
friend attaches so much importance."

"Indeed, Holmes! What is it?"

"Only this: that I KNOW that that mark was not there when I examined the
hall yesterday. And now, Watson, let us have a little stroll round in
the sunshine."

With a confused brain, but with a heart into which some warmth of hope
was returning, I accompanied my friend in a walk round the garden.
Holmes took each face of the house in turn and examined it with great
interest. He then led the way inside and went over the whole building
from basement to attics. Most of the rooms were unfurnished, but
none the less Holmes inspected them all minutely. Finally, on the top
corridor, which ran outside three untenanted bedrooms, he again was
seized with a spasm of merriment.

"There are really some very unique features about this case, Watson,"
said he. "I think it is time now that we took our friend Lestrade into
our confidence. He has had his little smile at our expense, and perhaps
we may do as much by him if my reading of this problem proves to be
correct. Yes, yes; I think I see how we should approach it."