"He's got the scent. Now watch him," and sharply he gave the word: "Va!"
Straight across the pavement darted Cæsar, then along the opposite sidewalk away from the Champs Elysées, running easily, nose down, past the Rue François Premier, past the Rue Clement-Marot, then out into the street again and stopping suddenly.
"He's lost it," mourned Papa Tignol.
"Lost it? Of course he's lost it," triumphed the detective. And turning to M. Gritz: "There's where your murderer picked up a cab. It's perfectly clear. No one has touched that pistol since the man who used it threw it from the window of Number Seven."
"You mean Number Six," corrected Gritz.
"I mean Number Seven. We know where the murderer took a cab, now we'll see where he left the hotel." And hurrying toward his dog, he called: "Back, Cæsar!"
Obediently the dog trotted back along the trail, recrossing the street where he had crossed it before, and presently reaching the point where he had first caught the scent. Here he stopped, waiting for orders, eying M. Paul with almost speaking intelligence.
"A wonderful dog," admired Gritz. "What kind is he?"
"Belgian shepherd dog," answered Coquenil. "He cost me five hundred francs, and I wouldn't sell him for—well, I wouldn't sell him." He bent over and fondled the panting animal. "We wouldn't sell our best friend, would we, Cæsar?"
Evidently Cæsar did not think this the moment for sentiment; he growled impatiently, straining toward the scent.