“It's a bit subtler than that, inspector. Now I admit quite frankly that this is all pure hypothesis; I'm merely trying it out, so to speak, so that we can feel certain we've covered all the possibilities. But here it is, for what it's worth. I'll put it in a nutshell for you. Amyl nitrite, when you inhale it, produces a rush of blood to the brain.” “And Peter Hay suffered from high blood-pressure in any case,” Wendover broke in, “so an extra flood of blood rushing to the head would finish him? Is that what you mean?” “Well, it's always a possibility, isn't it?” Sir Clinton returned. “Even a slight dose—a couple of sniffs—will give you a fair headache for the rest of the afternoon. It's beastly stuff.” Inspector Armadale ruminated for a moment or two. “Then you think that when they'd done with him they dosed him with this stuff and gave him an apoplectic stroke, sir?” “It could be done easily enough,” Sir Clinton said cautiously. “A teaspoonful of the stuff on a bit of cotton-wool under his nose would do the trick, if he was liable to a stroke. But they didn't do it in the cottage. They must have carried him out here, chair and all, and dosed him in the open air, or else we'd have smelt the stuff strongly in the room, even after this time. Perhaps that's what suggested leaving him outside all night, so that the stuff would evaporate from him as far as possible. We'll know for certain after the P. M. His lungs ought to have a fair amount of the nitrite in them, at any rate, if that notion's correct.” He paused for a time, then continued: “Now I don't say that it _is_ correct. We don't know for certain yet. But let's assume that it is, and see if it takes us any further. They must have procured the amyl nitrite beforehand and brought it here on purpose to use it. Now amyl nitrite won't kill an ordinary man. Therefore they must have known the state of Peter Hay's health. And they must have known, too, that he kept some sweets in the house always. My impression is that they brought that bag of pear-drops with them and took away Peter's own bag—which probably hadn't pear-drops in it. You'd better make a note to look into Peter's sweet-buying in the village lately, inspector. Find out what he bought last.” Sir Clinton pitched his cigarette-end over the hedge and took out his case. “You see what these things point to?” he inquired, as he lit his fresh cigarette. “It's easy enough to see, when you put it that way,” Wendover replied. “You mean that if they knew about Peter's health and Peter's ways to that extent, they must be local people and not strangers.”