ves like a gibbering idiot."

To this Thorndyke made no reply but a broad and appreciative smile, and
we descended to the lower floor. As we entered the room, the stranger
rose, and, glancing in an embarrassed way from one of us to the other,
suddenly broke out into an undeniable snigger. I looked at him sternly,
and Thorndyke, quite unmoved by his indecorous behaviour, said in a
grave voice:

"Let me introduce you, Jervis; though I think you have met this
gentleman before."

"I think not," I said stiffly.

"Oh yes, you have, sir," interposed the stranger; and, as he spoke, I
started; for the voice was uncommonly like the familiar voice of Polton.

I looked at the speaker with sudden suspicion. And now I could see that
the flaxen hair was a wig; that the beard had a decidedly artificial
look, and that the eyes that beamed through the spectacles were
remarkably like the eyes of our factotum. But the blotchy face, the
bulbous nose and the shaggy, overhanging eyebrows were alien features
that I could not reconcile with the personality of our refined and
aristocratic-looking little assistant.

"Is this a practical joke?" I asked.

"No," replied Thorndyke; "it is a demonstration. When we were talking
this morning it appeared to me that you did not realize the extent to
which it is possible to conceal identity under suitable conditions of
light. So I arranged, with Polton's rather reluctant assistance, to give
you ocular evidence. The conditions are not favourable--which makes the
demonstration more convincing. This is a very well-lighted room and
Polton is a very poor actor; in spite of which it has been possible for
you to sit opposite him for several minutes and look at him, I have no
doubt, very attentively, without discovering his identity. If the room
had been lighted only with a candle, and Polton had been equal to the
task of supporting his make-up with an appropriate voice and manner, the
deception would have been perfect."

"I can see that he has a wig on, quite plainly," said I.

"Yes; but you would not in a dimly lighted room. On the other hand, if
Polton were to walk down Fleet Street at mid-day in this condition, the
make-up would be conspicuously evident to any moderately observant
passer-by. The secret of making up consists in a careful adjustment to
the conditions of light and distance in which the make-up is to be seen.
That in use on the stage would look ridiculous in an ordinary room; that
which