Surely my whole chain of reasoning cannot have been false. It isimpossible！ And yet this wretched dog is none the worse. Ah， Ihave it！ I have it！” With a perfect shriek of delight he rushed tothe box， cut the other pill in two， dissolved it， added milk， andpresented it to the terrier. The unfortunate creature’s tongueseemed hardly to have been moistened in it before it gave aconvulsive shiver in every limb， and lay as rigid and lifeless as if ithad been struck by lightning.
Sherlock Holmes drew a long breath， and wiped the perspirationfrom his forehead. “I should have more faith，” he said； “I ought toknow by this time that when a fact appears to be opposed to a longtrain of deductions， it invariably proves to be capable of bearingsome other interpretation. Of the two pills in that box， one wasof the most deadly poison， and the other was entirely harmless. Iought to have known that before ever I saw the box at all.”
This last statement appeared to me to be so startling that Icould hardly believe that he was in his sober senses. There was thedead dog， however， to prove that his conjecture had been correct.
It seemed to me that the mists in my own mind were graduallyclearing away， and I began to have a dim， vague perception of thetruth.
“All this seems strange to you，” continued Holmes， “because youfailed at the beginning of the inquiry to grasp the importance ofthe single real clue which was presented to you. I had the goodfortune to seize upon that， and everything which has occurredsince then has served to confirm my original supposition， and，indeed， was the logical sequence of it. Hence things which haveperplexed you and made the case more obscure have served toenlighten me and to strengthen my conclusions. It is a mistaketo confound strangeness with mystery. The most commonplacecrime is often the most mysterious， because it presents no newor special features from which deductions may be drawn. Thismurder would have been infinitely more difficult to unravel hadthe body of the victim been simply found lying in the roadwaywithout any of those outré and sensational accompanimentswhich have rendered it remarkable. These strange details， farfrom making the case more difficult， have really had the effect ofmaking it less so.”
Mr. Gregson， who had listened to this address with considerableimpatience， could contain himself no longer. “Look here， Mr.
Sherlock Holmes，” he said， “we are all ready to acknowledgethat you are a smart man， and that you have your own methodsof working. We want something more than mere theory andpreaching now， though. It is a case of taking the man. I have mademy case out， and it seems I was wrong. Young Charpentier couldnot have been engaged in this second affair. Lestrade went afterhis man， Stangerson， and it appears that he was wrong too. Youhave thrown out hints here， and hints there， and seem to knowmore than we do， but the time has come when we feel that wehave a right to ask you straight how much you do know of thebusiness. Can you name the man who did it？”
“I cannot help feeling that Gregson is right， sir，” remarkedLestrade. “We have both tried， and we have both failed. You haveremarked more than once since I have been in the room thatyou had all the evidence which you require. Surely you will notwithhold it any longer.”
“Any delay in arresting the assassin，” I observed， “might give himtime to perpetrate some fresh atrocity.”
Thus pressed by us all， Holmes showed signs of irresolution. Hecontinued to walk up and down the room with his head sunk onhis chest and his brows drawn down， as was his habit when lost inthought.
“There will be no more murders，” he said at last， stoppingabruptly and facing us. “You can put that consideration out of thequestion. You have asked me if I know the name of the assassin.
I do. The mere knowing of his name is a small thing， however，compared with the power of laying our hands upon him. ThisI expect very shortly to do. I have good hopes of managing itthrough my own arrangements； but it is a thing which needsdelicate handling， for we have a shrewd and desperate man todeal with， who is supported， as I have had occasion to prove， byanother who is as clever as himself. As long as this man has no ideathat anyone can have a clue there is some chance of securing him；but if he had the slightest suspicion， he would change his name，and vanish in an instant among the four million inhabitants ofthis great city. Without meaning to hurt either of your feelings，I am bound to say that I consider these men to be more than amatch for the official force， and that is why I have not asked yourassistance. If I fail， I shall， of course， incur all the blame due tothis omission； but that I am prepared for. At present I am ready topromise that the instant that I can communicate with you withoutendangering my own combinations， I shall do so.”
Gregson and Lestrade seemed to be far from satisfied by thisassurance， or by the depreciating allusion to the detective police.
The former had flushed up to the roots of his flaxen hair， whilethe other’s beady eyes glistened with curiosity and resentment.
Neither of them had time to speak， however， before there wasa tap at the door and the spokesman of the street Arabs， youngWiggins， introduced his insignificant and unsavoury person.
“Please， sir，” he said， touching his forelock， “I have the cabdownstairs.”
“Good boy，” said Holmes， blandly. “Why don’t you introducethis pattern at Scotland Yard？” he continued， taking a pair of steelhandcuffs from a drawer. “See how beautifully the spring works.
They fasten in an instant.”
“The old pattern is good enough，” remarked Lestrade， “if we canonly find the man to put them on.”
“Very good， very good，” said Holmes， smiling. “The cabman mayas well help me with my boxes. Just ask him to step up， Wiggins.”