The Roman Hat Mystery

“I took a healthy rabbit, of the sort we use for experiment, and painted — just painted, mind you — the tender area behind the creature’s ear with an undiluted dose of the stuff. Re-member, this was not an internal injection. It was merely a painting of the skin. It would have to be absorbed through the dermis before it reached the bloodstream. I watched the rabbit for an hour — and after that I didn’t have to watch him any more. He was as dead as any dead rabbit I ever saw.”

“That doesn’t seem so powerful to me, Doctor,” protested the Inspector.

“It doesn’t, eh? Well, take my word for it that it’s extraordinary. For a mere daubing of whole, healthy skin — I tell you, I was astounded. If the skin had an incision of some sort, or if the poison were administered internally, that would be a different story. You can imagine, therefore, what happened to Field’s insides when he swallowed the stuff — and he swallowed plenty!”

Ellery’s brow was wrinkled in thought. He began to polish the lenses of his pince-nez.

“And that isn’t all,” resumed Dr. Jones. “As far as I know — and I have been in the service of the city for God knows how many years, and I’ve not kept uninformed about the progress of my science in other parts of the world, either — as far as I know, terra ethyl lead has never before been used for criminal purposes!”

The Inspector drew up, startled. “That’s saying something, Doctor!” he muttered. “Are you sure?”

“Positive. That’s why I’m so keenly interested.”

“Just how long would it take for this poison to kill a man, Doctor?” asked Ellery slowly.

Dr. Jones grimaced. “That’s something I can’t answer definitely, for the very good reason that to my knowledge no human being has ever died of its effects before. But I can make a fairly good guess. I can’t conceive of Field having lived more than fifteen to twenty minutes at the utmost after having taken the poison internally.”

The silence that followed was broken by a cough from Queen. “On the other hand, Doctor, this very strangeness of the poison should make it fairly easy to trace. What, would you say, is its commonest source? Where does it come from? How would I go about getting it if I wanted some for a criminal purpose and didn’t want to leave a trail?”

A gaunt smile lit up the features of the toxicologist “The job of tracing this stuff, Inspector,” he said fervently, “I’ll leave to you. You can have it. Tetra ethyl lead, as far as I’ve been able to determine — remember, it is almost entirely new to us — occurs most commonly in certain petroleum products. I tinkered around quite a bit before I found the easiest way of making it in quantity. You’ll never guess how it’s done. It can be extracted from common, ordinary, everyday gasoline!”

The two Queens exclaimed under their breaths. “Gasoline!” cried the Inspector. “Why — how on earth could a man trace that?”

“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 whisky, eh, Doctor?” asked Queen abstractedly.