"In this case it certainly is so," I replied after a little thought. "The thing, however, is, as you say, of the simplest. Would you think me impertinent if I were to put your theories to a more severe test?"
"On the contrary," he answered, "it would prevent me from taking a second dose of cocaine. I should be delighted to look into any problem which you might submit to me."
"I have heard you say it is difficult for a man to have any object in daily use without leaving the impress of his individuality upon it in such a way that a trained observer might read it.
Now, I have here a watch which has recently come into my possession.
Would you have the kindness to let me have an opinion upon the character or habits of the late owner?"
I handed him over the watch with some slight feeling of amusement in my heart, for the test was, as I thought, an impossible one, and I intended it as a lesson against the somewhat dogmatic tone which he occasionally assumed.
He balanced the watch in his hand, gazed hard at the dial, opened the back, and examined the works, first with his naked eyes and then with a powerful convex lens.
I could hardly keep from smiling at his crestfallen face when he finally snapped the case to and handed it back.
"There are hardly any data," he remarked. "The watch has been recently cleaned, which robs me of my most suggestive facts. "
"You are right," I answered. "It was cleaned before being sent to me."