Galvanised by terror, the clerk leaped from the bed and collapsed before Mr Holmes. He clung to Holmes's legs and sobbed: 'I confess. I confess. The thing is in the lamp. It is a trap. Let me out of the room before…'
Just then there was a sharp click from the lamp, and as we looked up a littie hatch swung openfrom the bottom of the elephant and a small, bright object fell on the bed. The clerk screamed with horror. The thing was red and shiny, no longer than six inches and about the thickness and shape of a piece of garden hose. It rose up, one end poised in the air, wiggling from side to side.
'What the deuce is it?' said Strickland.
'Devilry,' answered Holmes, reaching into his pocket.
Just then the thing stopped swaying, stiffened for a moment, then with remarkable speed, began to move towards us. Though the desk-clerk's terror was certainly most contagious, my scientific curiosity compelled me to observe the curious method by which the creature effected locomotion. The moment it dropped its upper end on the ground its rear end rose up and wiggled forward.
The upper end rose again and looped forwards with the rear end following immediately. The creature performed this operation with surprising speed and came rapidly towards us.
The clerk backed away in horror and tumbled backwards over my chair. Strickland and I, though certainly not as frightened as he was, recoiled slightly from the advancing creature, vaguely aware of the menace that lurked in it despite its insignificant size. Only Sherlock Holmes was absolutely unperturbed. He remained calmly seated in his chair, and, as the thing got near his legs, reached into his pocket, pulled out a silver salt-cellar, and bending over poured the contents over the creature. As soon as the salt touched its body it began to squirm and flick about violently, as if in tremendous agony.
'Why, it is a leech!' I exclaimed in surprise.
'But not your common or garden variety,' said Holmes gravely. 'This one is a Giant Red Leech [16] of the Lower Himalayas, Hirudinea Himalayaca Giganticus, of the genus Haemadipsa. We must thank a kindly providence for restricting its existence to the small district of Kaladhungi in the Western Himalayas. Only its extreme rarity-has cloaked its well-deserved reputation as a deadly killer. You may know that the saliva of the common leech contains chemical substances that not only anaesthetises the wound area, but also contain the anti-coagulant hirudin, which is used medically, and which prevents the blood from clotting. My reading this morning at the Natural History Museum informed me that the Giant Red Leech is not only much larger than the common leech, of which about three hundred species are known, but that its saliva contains these chemicals in concentrations many thousands of times stronger’.
'No wonder the poor chap bled as extensively as he did,' I said, in dread awe.
'That is not all,' said Holmes grimly, checking the notes on his cuff. 'Two other complex chemical substances are present in the Giant Leech's saliva. One activates the allergy reaction system in the body tissues to produce histamine, an amine concentrate formed from histidine, which dilates blood vessels and the pores of the skin. The third substance causes massive Paroxysmal tachycardia, a condition in which the heart suddenly commences to beat at an extraordinarily rapid rate – from two hundred and fifty to three hundred beats a minute – for a considerable period of time. So, once the saliva was absorbed into the blood-stream you would have a cumulative situation where a tremendously agitated heart would violently pump all the enervated blood from the body out of every dilated pore in the skin.'
'My God,' said Strickland with a shudder. 'But how did the creature get to him in the first place?'
'It dropped on the back of his neck when he bent over to straighten out the bedclothes.'
'That explains the marks on his neck,' exclaimed Strickland.
'Yes. The leech has three jaws, set with sharp teeth, that make the typical Y-shaped incision that I sketched for you a little while ago. The jaws and suckers on the mouth grip theflesh tenaciously. It is possible that the victim managed to tear the leech off his neck only after he rushed out into the corridor in panic. That is where the blood stains start. He then probably flung the horrible thing on the ground and stamped it to death. Huree, you may remember it as the "piece of India rubber" that I discovered yesterday in the corridor. But of course the leech had already injected its deadly saliva into the man, and from then on there was nothing any one could have done to prevent his heart from pumping his life blood out of his body. There was so much anti-coagulant in the blood that even after spilling on the floor and being exposed to the air for more than an hour, it showed no sign of drying.'
'You chanced to remark on it yesterday when we were coming down to the lobby after your investigations, Mr Holmes/ I exclaimed, remembering.
But Sherlock Holmes was already occupied in climbing onto the table he had pushed by the bed. He reached for the lamp, and, holding it delicately with a handkerchief, unfastened it from the chains that suspended it from the ceiling. He then jumped lightiy off the table and placed the elephant on it.
'Humm. Ingenious. A unique and terrible weapon,' said he, examining the elephant closely. 'And yet such an exquisite work of art. Notice how the heat of the lamp inside the canopied box…'
'The howdah, Sir,' I corrected him.
'Thank you,' he replied brusquely,'… how the heat of the lamp inside the howdah is transferred to the belly of the elephant by these copper wires. The heat gradually melts the wax that holds this small hatch in the elephant's belly and then, after a period of time regulated by the thickness of the wax used, allows the hatch to fall open and lets the creature out. I experimented on the hatch last night and discovered that it would not be possible for it to remain closed – once the lamp had been lit – for longer than two hours. So I was reasonably sure that no one would prepare the devilish thing again before the evening. Just to be on the safe side though, I asked you, Strickland, to be in my room before sunset. When I met Mr Carvallo in the lobby I informed him that I would be retiring after an early supper. So our friend was able to time his move nicely, while I had a light repast and thereafter borrowed a full salt-cellar.'
'But what went wrong yesterday, Mr Holmes?' I asked.
'Our nervous friend here…' Holmes turned to the clerk, who was cowering in the corner of the room,'… used too much heat to stick the wax on the hatch yesterday, thereby causing a portion of it to drip on the counterpane. This thinned the seal and caused the premature opening of the hatch. But I apportion too much blame to you, Mr Carvallo. It was, after all, a most desperate commission, and remarkable that such a faint-hearted person as yourself should have attempted to undertake it. It would tax the limits of any man's courage to handle such a creature once – but twice! That was above and beyond the call of duty. Or was it because your master does not tolerate failure? A hard man, is he not? It would be difficult to imagine someone more unforgiving than the villain whom you have the misfortune to serve. What kind of hold does he have on you?'
'I cannot tell.' The wretch sank his face in his hands. 'It is too late,' he sobbed. After a while he raised his head and with great effort attempted to get a hold of himself. Taking a deep breath he spoke, a note of hopeless defiance heightening the pathos in his voice. 'No, gentlemen, I cannot tell. Whatever fate the law may impose on me, it will be a kinder one than what I will surely suffer if I betray my master.'
'Oh, you think so, do you?' said Strickland harshly, snapping a pair of handcuffs on him. 'Let me tell you, my man, that if I have anything to say about it you'll hang from the highest gallows in the Bombay Presidency.' He turned to me. 'Kindly ring the bell, Huree.'