who shared your cab in your drive this morning."

"I don't admit that a fresh illustration is an explanation," said
I with some asperity.

"Bravo, Watson! A very dignified and logical remonstrance. Let
me see, what were the points? Take the last one first--the cab.
You observe that you have some splashes on the left sleeve and
shoulder of your coat. Had you sat in the centre of a hansom you
would probably have had no splashes, and if you had they would
certainly have been symmetrical. Therefore it is clear that you
sat at the side. Therefore it is equally clear that you had a
companion."

"That is very evident."

"Absurdly commonplace, is it not?"

"But the boots and the bath?"

"Equally childish. You are in the habit of doing up your boots
in a certain way. I see them on this occasion fastened with an
elaborate double bow, which is not your usual method of tying
them. You have, therefore, had them off. Who has tied them? A
bootmaker--or the boy at the bath. It is unlikely that it is the
bootmaker, since your boots are nearly new. Well, what remains?
The bath. Absurd, is it not? But, for all that, the Turkish
bath has served a purpose."

"What is that?"