Inference - that your brother was often at low water.
Secondary inference - that he had occasional bursts of prosperity, or he could not have redeemed the pledge.
Finally, I ask you to look at the inner plate, which contains the keyhole.
Look at the thousands of scratches all round the hole - marks where the key has slipped.
What sober man's key could have scored those grooves? But you will never see a drunkard's watch without them.
He winds it at night, and he leaves these traces of his unsteady hand.
Where is the mystery in all this?"
"It is as clear as daylight," I answered. "I regret the injustice which I did you. I should have had more faith in your marvellous faculty. May I ask whether you have any professional inquiry on foot at present?"
"None.
Hence the cocaine.