cigarette of which only half-an-inch had been smoked.
"How instructive?" I asked. "What do you learn from it?"
"Many things," he replied. "It has been lit and thrown away unsmoked; that indicates a sudden change of purpose. It was thrown away at the entrance to the house, almost certainly by someone entering it. That person was probably a stranger, or he would have taken it in with him. But he had not expected to enter the house, or he would not have lit it. These are the general suggestions; now as to the particular ones. The paper of the cigarette is of the kind known as the 'Zig-Zag' brand; the very conspicuous water-mark is quite easy to see. Now Brodski's cigarette book was a 'Zig-Zag' book—so called from the way in which the papers pull out. But let us see what the tobacco is like." With a pin from his coat, he hooked out from the unburned end a wisp of dark, dirty brown tobacco, which he held out for my inspection.
"Fine-cut Latakia," I pronounced, without hesitation.
"Very well," said Thorndyke. "Here is a cigarette made of an unusual tobacco similar to that in Brodski's pouch and wrapped in an unusual paper similar to those in Brodski's cigarette book. With due regard to the fourth rule of the syllogism,
