“That’s the point,” answered the toxicologist. “I could go to the corner gas-station, fill up the tank of my car, run it home, extract some of the gasoline from the tank, go into my laboratory and distill the tetra ethyl lead in remarkably little time with remarkably little effort!” “Doesn’t that imply, Doctor,” put in Ellery hopefully, “that the murderer of Field had some laboratory experience—knew something about chemical analysis, and all that sort of rot?” “No, it doesn’t. Any man with a home-brew ‘still’ in his house could distill that poison without leaving a trace. The beauty of the process is that the tetra ethyl lead in the gasoline has a higher boiling-point than any other of the fluid’s constituents. All you have to do is distill everything out up to a certain temperature, and what’s left is this poison.” The Inspector took a pinch of snuff with trembling fingers. “All I can say is—I take my hat off to the murderer,” he muttered. “Tell me—Doctor—wouldn’t a man have to know quite a bit about toxicology to possess such knowledge? How could he ever know this without some special interest—and therefore training—in the subject?” Dr. Jones snorted. “Inspector, I’m surprised at you. Your question is already answered.” “How? What do you mean?” “Haven’t I just told you how to do it? And if you heard about the poison from a toxicologist, couldn’t you make some provided you had the ‘still’? You would require no knowledge except the boiling-point of tetra ethyl lead. Get along with you, Queen! You haven’t a chance in the world of tracing the murderer through the poison. In all probability he overheard a conversation between two toxicologists, or even between two medical men who had heard about the stuff. The rest was easy. I’m not saying this is so. The man might be a chemist, at that. But I’m concerned only in giving you the possibilities.” “I suppose it was administered in whiskey, eh, Doctor?” asked Queen abstractedly. “No doubt about it,” returned the toxicologist. “The stomach showed a large whiskey content. Certainly, it would be an easy way for the murderer to slip it over on his victim. With the whiskey you get nowadays, most of it smells etherized, anyway. And besides, Field probably had it down before he realized anything was wrong—if he did at all.” “Wouldn’t he taste the stuff?” asked Ellery wearily. “I’ve never tasted it, young man, so I can’t say definitely,” answered Dr. Jones, a trifle tartly. “But I doubt whether he would—sufficiently to alarm him, at any rate. Once he had it down it wouldn’t make any difference.” Queen turned to Prouty, whose cigar had gone out. He had fallen into a hearty doze. “Say, Doc!” Prouty opened his eyes sleepily. “Where are my slippers—I can’t ever seem to find my slippers, damn it!”