"There now," said he, as he prepared to write, "I shall begin with what I shall call the Cab Mystery. The data in this case are already plentiful and curious. I shall read as I write, and you can interrupt for suggestions and criticisms, as the points occur to you. In the first place, then, the dead man is about fifty years old, and was employed in some commercial house or financial institution, probably as bookkeeper, at a fairly good salary." "Hold on there, Sturgis," laughed Thurston. "I thought you were going to build up a solid foundation of facts before you allowed your imagination to run riot!" "Well?" inquired the reporter in apparent surprise. "Well, the only fact you have mentioned is the approximate age of the dead man. The rest is pure assumption. How can you know anything certain about his occupation and the amount of his salary?" "True; I forgot you had not followed the steps in the process of induction. Here they are: the dead man's sleeves, on the under side below the elbow, were worn shiny. This shows that his occupation is at a desk of some kind." "Or behind a counter," suggested Thurston quizzically. "No. Your hypothesis is untenable. A clerk behind a counter does occasionally, it is true, lean upon his forearms. But incessant contact with the counter leaves across the front of his trousers an unmistakable line of wear, at a level varying according to the height of the individual. This line was not present in the case of the man in the cab. On the other hand, his waistcoat is frayed and worn at the level of the fourth button from the top. Therefore I maintain that he was in the habit of working at a desk. Now the trousers, although not new, are not baggy at the knees, though free from the seams which would suggest the effect of pressing or of a trousers stretcher. Conclusion, the desk is a high one; for the man stood at his work. Most men who work standing at high desks are bookkeepers of one kind or another. Therefore, as I said before, this man was probably a bookkeeper. Now, as to his salary; I do not pretend to know the exact amount of it, of course. But when a man, who was evidently not a dude, has his clothes made to order, of imported material, and when his linen, his hat and his shoes are of good quality, it is fair to infer that the man's income was comfortable. "I proceed with the arrangement of my data: "Secondly: the man in the cab died of a wound caused by a bullet fired at very close quarters. Indeed, the weapon must have been held either against the victim's body, or, at any rate, very near to it; for the coat is badly burned by the powder." "On these points at least," assented Doctor Thurston, "I can agree with you. The bullet probably penetrated the upper lobe of the left lung." "Yes," added Sturgis, "and it passed out at the back, far below where it went in." "What makes you think it passed out? The wound in the back may have been caused by another bullet fired from the rear."