“I should be glad, Watson, if you could head into town as quickly as you can,” he said calmly. “Return with a dog-cart and several able-bodied men. I shall remain here with Sir Percival.”
The rest of the particulars can be summed up in short order. After Sir Percival was taken up by the authorities and remanded to the police-court, we returned to Aspern Hall. Holmes spoke briefly, in turn, with the magistrate; young Edwin Aspern; and Miss Selkirk, and then insisted on our returning to London by the very next train.
“I must confess, Holmes,” I told him as our carriage made its way along the road back towards Hexham just as dawn was breaking, “that whilst I have often been in the dark in past cases, this is your most singular surprise yet. Without doubt it will prove your coup-de-mâitre. How on earth did you know that a human, not a wolf, was behind these outrages — and how in particular did you know it was Sir Percival, if in fact you knew that at all?”
“My dear Watson, you do me a disservice,” Holmes replied. “Naturally I knew it was Sir Percival.”
“Then pray explain yourself.”
“Several clues presented themselves, for anyone with the discernment to sift the important from the mere coincident. To begin with, we have the madman — the first victim. When there is more than one killing to reckon with, Watson, you must always pay particular attention to the first. Frequently the motive, and therefore the entire case, rests upon that particular crime.”
“Yes, but the first victim was nothing but a mindless vagrant.”
“He might have been so in recent years, but he was not always thus. Recall, Watson, that in his ravings, a single word stood out again and again: carrot.”
I recalled this, and Holmes’s fascination with it, all too well. How it could have any significance seemed to defy credibility. “Go on,” I said.
“Carroting, you must understand, was a process by which animal fur is bathed in a solution of mercury nitrate, in order to render the hairs more supple, thus producing a superior felt.” At this last word, he threw a significant glance in my direction.
“Felt,” I repeated. “You mean, for the making of hats?”
“Precisely. The solution is of an orange colour, hence the term carroting. However, this process had rather severe side effects on those who worked with it, which is why its use today is much reduced. When mercury vapours are inhaled over a long enough period of time — particularly, for our purposes, in the close quarters of a hat-making operation — toxic and irreversible effects almost inevitably follow. One develops tremors of the hands; blackened teeth; slurred speech. In severe cases, dementia or outright insanity can occur. Hence the term mad as a hatter.” Holmes waved a hand. “I know all this, of course, due to my long-abiding interest in chemistry.”
“But what does all this have to do with Sir Percival?” I asked.
“Let us proceed in a linear fashion, if you please. You will recall that Constable Frazier believed our vagabond to be a drunkard, citing as evidence the man’s slurred speech and impaired movement. And yet he detected no smell of alcohol on the man’s breath. I immediately assumed that the real cause of the man’s affliction was not drunkenness, but rather the effects of mercury poisoning. His mention of ‘carrots’ explained how this poisoning had come about: as an occupational hazard of making felt, from working as a hatter. I naturally realized that there could be no coincidence between Sir Percival’s former occupation and the sudden arrival of this curious fellow upon the scene. No: this man had clearly once been in business with Sir Percival. Recall, if you will, two things. First, how this man had raved about betrayal, about getting a judgement from a court of law. Second, how Sir Percival made his fortune by a unique felt-making process — a process, you may recollect, he refused to discuss with me when I broached the topic at Aspern Hall.”
The carriage continued its jostling way towards Hexham, and Holmes went on. “Remarking on these facts, I began to consider the possibility that this man, now sadly reduced, had once been Sir Percival’s business partner — and, perhaps, the true author of that revolutionary felt-making process. Now, years later, he had returned to square accounts with his former partner, to expose and ruin him. In other words, this whole matter began as a mere business dispute; one that Sir Percival solved in a traditional manner — by murder. It seemed to me highly likely that when this fellow appeared in Hexham, Sir Percival had promised him amends, and had agreed to meet with him in a lonely spot at the edge of the bog. There, Sir Percival murdered his former partner, and — to keep any suspicion from ever redounding upon him — tore the body cruelly, even going so far as to leave some tentative bite marks, so as to make it appear the work of a large and savage beast, most likely a wolf.”
“And in so doing, he seemed to have been entirely successful,” I said. “Why, then, kill again?”
“The second person killed, you will recall, was a naturalist from Oxford. He was heard in the local inn debunking the rumours of a wolf, declaring that no wolves still survived in England. By killing this man, Sir Percival accomplished several goals. He silenced the man’s insistence on the extinction of the English wolf — the very last thing Sir Percival would want was attention returning to the initial killing. Also, by this time he had of course heard the rumours in Hexham about a wolf being the culprit in his partner’s murder. In case he was spotted, he had now had the opportunity to fit out a large bear coat, complete with wolf-paw gloves and boots that he — with his hatter’s skill — could make entirely convincing. He used this disguise to run to and from the second murder scene on all fours. I believe, Watson, he was actually hopingfor a witness this time, in order to inflame the rumours of a man-eating wolf. In this, at least, he was fortunate.”
“Yes, I can see a cruel logic in such a course of action,” I said. “But what, then, of the constable?”
“Constable Frazier was, if not the world’s most accomplished investigator, a man of great doggedness and persistence. No doubt Sir Percival perceived him to be a threat. Recall how the constable hinted at certain suspicions about the wolf’s behaviour. Those suspicions, I would hazard, had to do with why the wolf tracks entered the bog but never came out again. The constable would have remarked on this after the second murder, if not before. I myself found this curious phenomenon to be the case after the constable’s own death, when I made a circuit of the bog. Wolf tracks entered the region from the east; only human tracks emerged from the west. Sir Percival, you see, would have entered the bog on all fours, as a wolf; he would have used the concealing vegetation to come out from the bog as merely himself, should anyone encounter him. The constable must have mentioned his suspicions to Sir Percival — remember, Watson, his remarking he’d been to the Hall just the day before, to warn young Aspern to cease his hunting of the wolf — and in so doing, signed his own death warrant.”
Hearing these revelations, presented in Holmes’s complacent tone, was nothing less than astounding. I could only shake my head.
“What clinched the case for me was Sir Percival’s cavalier, indeed encouraging, attitude towards his son’s hunting of the beast. He seemed to evince total unconcern for young Edwin’s well-being. Why? At this point in the game, the answer was obvious to me: he knew his son was in no danger from the wolf, because the wolf was himself. Then, of course, there was the manner in which Sir Percival spilt his brandy.”
“What of it?”
“He was making great pains to hide his trembling hands. That incipient palsy demonstrated to my satisfaction that he himself was well on the road to madness brought on by mercury poisoning, and that he would soon be reduced to the same pitiable state as his former partner.”