XI - Deduction–––––––– MR. REEDER KEPT WHAT he called a casebook, in which he inscribed passionless account of all the cases in which he was engaged. Some of these cases had no value except to the technician, and would not interest anyone except perhaps the psychopathologist. Under the heading 'Two Aces' appeared this account, written in his own handwriting. 'Ten years ago,'—wrote Mr Reeder—' there arrived at the Hotel Majestic in Nice a man who described himself in the hotel register as Rufus Machfield. He had a number of other names, but it is only necessary that Machfield should be used to identify this particular character. The man had a reputation as a cardsharp and, in the pursuit of his nefarious calling, had 'worked' the ships plying between England and New York. He had also been