“Yes, I do,” said Mr. Upton, remembering the annoying letter he seemed to have received some weeks before. “He smokes, against his doctor’s orders.” “Do you mean tobacco?” “No—some stuff for asthma.” “In cigarettes?” “Yes.” “Do you know the name?” “I have it here.” The offensive letter was not only produced, but offered for inspection after a precautionary glance. Thrush was on his feet to receive it in outstretched hand. Already he looked extraordinarily keen for his bulk, but the reading of the letter left him alive and alert to the last superfluous ounce. “But this is magnificent!” he cried, with eyes as round as their glasses. “I confess I don’t see why.” “Cigarettes d’Auvergne!” “Some French rubbish.” “The boy has evidently been dependent on them?” “It looks like it.” “And this man Bompas made him give them all up?” “So he has the impudence to say.” “Is it possible you don’t see the importance of all this?” Mr. Upton confessed incompetence unashamed. “I never heard of these cigarettes before; they’re an imported article; you can’t get them everywhere, I’ll swear! Your boy has got to rely on them; he’s out of reach of the doctor who’s forbidden them; he’ll try to get them somewhere! If he’s been trying in London, I’ll find out where before I’m twenty-four hours older!” “But how can you?” asked Mr. Upton, less impressed with the possibility than by this rapid if obvious piece of reasoning. “A. V. M.!” replied Eugene Thrush, with cryptic smile. “Who on earth is he?” “Nobody; it’s the principle on which I work.” “A. V. M.?” “Otherwise the old nursery game of Animal, Vegetable, or Mineral.” Again Mr. Upton had to prevent himself by main force from declaring it all no laughing matter; but his silence was almost bellicose. “You divide things into two,” explained Thrush, “and go on so dividing them until you come down to the indivisible unit which is the answer to the riddle. Animal or Vegetable? Vegetable or Mineral? Northern or Southern Hemisphere? Ah! I thought your childhood was not so very much longer ago than mine.” Mr. Upton had shrugged an impatient recognition of the game. “In this case it’s Chemists Who Do Sell D’Auvergne Cigarettes and Chemists Who Don’t. Then—Chemists Who Do and Did Yesterday, and Chemists Who Do but Didn’t! But we can probably improve on the old game by playing both rounds at once.” “I confess I don’t quite follow,” said Mr. Upton, “though there seems some method in the madness.” “It’s all the method I’ve got,” rejoined Thrush frankly. “But you shall see it working, for unless I’m much mistaken this is Mullins back sooner than I expected.”