all morning. I see also in your open desk there that you have a sheet of stamps and a thick bundle of postcards. What could you go into the post-office for, then, but to send a wire? Eliminate all other factors, and the one which remains must be the truth.'
'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 that 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
