Mike Ashley - The Mammoth Book of New Sherlock Holmes Adventures

"Most instructive," said Holmes dreamily.

Traill continued: "The horror was unspeakable. The leech clung to my hand, biting with a burning pain, rendering me too horrified to move. I was lucky that a doctor was passing by, who recognized the awful thing! He plucked it from my flesh with a gloved hand and threw it aside into the undergrowth.

And then, straight away, on the grass of Hampstead Heath, this Dr James unpacked his surgical instruments from his black bag and cut the mouth-parts of the horrid beast out of my hand, while I averted my gaze and struggled not to cry out. `A narrow escape young fellow,' he said to me. 'If my eye had not been caught by the press report' – and here he handed me the scrap of paper which you hold – 'it might have gone badly for you. There is something in Providence after all.' I thanked Dr James profusely, and at my insistence he charged me a guinea. Although he had dressed the tiny wound carefully, it was painful and slow to heal.

"And now you know why I fear madness. My mind seems unclouded, but my senses betray me – the leech-bitten hand burns like fire when I try to move against my sister's wishes, as though her infernal spirits were real after all."

"Quite so," said Holmes, regarding him with intense satisfaction through half-closed eyes. "Your case, Mr Trail, presents some extraordinarily interesting and gratifying features. Would you recognize Dr James if you met him again?"

"Certainly: his great black beard and tinted glasses were most distinctive."

This seemed to cause Holmes some private merriment. "Excellent! Yet you now consult the estimable but unfamiliar Watson, rather than the provenly knowledgeable James."

"I confess that in my over-excitement I must have misheard the address Dr James gave to me. There is no such house-number at the street in Hampstead where I sought him."

"Better still. The time has come to summon a cab, Watson! We can easily reach the Highgate Ponds before twilight."

"But to what purpose?" I cried. "After six months the creature will be long gone, or dead and rotted."

"Well, we may still amuse ourselves by catching tittlebats – as Mr Pickwick chose to call sticklebacks. The correct naming of creatures is so important, is it not?"

All through the long four-wheeler cab ride I struggled to make sense of this, while Holmes would talk of nothing but music.

In the bleak grey of late afternoon, Hampstead Heath was at its most desolate. A thin, cold rain continued to fall. The three of us trudged through wet grass on our fool's errand.

"I must ask you for a supreme effort of memory, Mr Traill," declared Holmes as the ponds came into view. "You must cast your mind back to that Tuesday in the spring. Remember the pattern of trees you saw as you sat on the ground; remember the dog that pranced in the water. We must know the exact place, to within a few feet."

Traill roamed around dubiously. "It all looks different at this time of year," he muttered. "Perhaps near here."

"Squat on your heels to obtain the same perspective as when you sat," suggested Holmes. After a few such reluctant experiments, our client indicated that he was as close as memory would take him.

"Then that patch of hawthorn must be our goal – the leech's last known domicile," Holmes observed. "Note, Watson, that this picnic-spot is several yards from the beaten path. The good Dr James must have been quite long-sighted, to see and recognize that leech."

"He might easily have been taking a short cut across the grass," I replied.

"Again the voice of reason pours cold water on my fanciful deductions!" said Holmes cheerfully. As he spoke, he methodically prodded the hawthorn bushes with his walking-stick, and turned over the sodden mass of fallen leaves beneath. He seemed oblivious to the chill drizzle, now made worse by a steadily rising wind from the east. A quarter of an hour went miserably past.

Then – "A long shot, Watson, a very long shot!" cried my friend, and pounced. From a pocket of his cape he had produced a pair of steel forceps, and from another a large pill-box. Now something red glistened in the forceps' grip, and in a trice the thing was safely boxed. Traill, who had given an involuntary cry, backed away a step or two with an expression of revulsion.

"Another of the vile creatures?"

"I fancy it is the same," Holmes murmured. And not a word more would he utter until we were installed in a convenient public house which supplied us with smoking-hot whisky toddies. "It is villainy, Mr Traill," he said then. "One final test remains. I experimented not long ago with a certain apparatus, without fully comprehending its possibilities in scientific detection…"

It was late night in Baker Street, and the gas-mantles burnt fitfully. A smell of ozone tinged the air, mingled with a more familiar chemical reek. Holmes, as he linked up an extensive battery of wet cells, expounded with fanciful enthusiasm on the alternating-current electrical transmission proposals of one Mr Nikola Tesla in the Americas, and of how in the early years of the new century he fully expected electric lighting to be plumbed into our lodgings, like the present gas-pipes. I smiled at his eagerness.

At length the preparations were complete. "You must refrain from touching any part of the equipment," Holmes now warned. "The electrical potential which drives this cathode-ray tube is dangerously high. Do you recognize the device, Watson? The evacuated glass, the tungsten target electrode within? It has already been employed in the United States, in connection with your own line of work."

The tangle of glassware, the trailing wires and the eerie glow from the tube made up an effect wholly unfamiliar to me, reminiscent perhaps of some new scientific romance by Mr H.G. Wells. It was only very gingerly that young Traill placed his right hand where Holmes directed.

"I have seen something a little like this before," he mused. "Old Wilfrid Jarman's brother dabbles in electrical experiments. He vexed Selina once with a tedious demonstration of a model dynamo."

"Healing rays?" I asked. "Earlier in the day we spoke of Mesmerism, which according to my recollection was a charlatan's ploy to heal by what he called animal magnetism. Has electrical science made this real at last?"

"Not precisely, Watson. The apparatus of Herr Doktor Röntgen does not heal, but lights the way for the healer. In years to come, I fancy it will be remembered as the greatest scientific discovery of the present decade."

"But I see nothing happening."

"That is what you may expect when there is nothing to see. – No, Mr Traill, I must entreat you to remain quite still. The rays of Röntgen, which he has named for algebra's unknown quantity X, do not impinge on the human eye. That faint glow which you may discern is not the true glow, but secondary fluorescence in the glass."

I pondered this, while Holmes kept a wary eye on his pocket-watch. "Very well," he said at last. "You may lift your hand now, but have a care…" And he took up the mysterious sealed envelope on which Traill's hand had rested. "What the eye cannot see, a photographic plate can still record. I must retreat to the darkroom and – lift the veil of the spirits. Kindly entertain our guest, Watson."

Traill and I stared at each other, lost in a mental darkness deeper than that of any photographic darkroom. Infuriatingly, I knew that to Holmes this night-shrouded terrain of crime was brilliantly lit by the invisible rays of his deductive power.

Nor was I much the wiser when morning came. Holmes, dancing-eyed and evasive, had bundled Traill into a homeward-bound hansom and directed him to return to Baker Street after breakfast, when the case would be resolved.Then he had settled into his favourite chair with his pipe and a pound of the vilest shag tobacco: I found him in the identical position when I arose from sleep.