Holmes had taken out his watch, and as minute followed minute without result, an expression of the utmost chagrin and disappointment appeared upon his features. He gnawed his lip, drummed his fingers upon the table, and showed every other symptom of acute impatience. So great was his emotion, that I felt sincerely sorry for him, while the two detectives smiled derisively, by no means displeased at this check which he had met.
“It can’t be a coincidence,” he cried, at last springing from his chair and pacing wildly up and down the room; “it is impossible that it should be a mere coincidence. The very pills which I suspected in the case of Drebber are actually found after the death of Stangerson. And yet they are inert. What can it mean? Surely my whole chain of reasoning cannot have been false. It is impossible! And yet this wretched dog is none the worse. Ah, I have it! I have it!”
With a perfect shriek of delight he rushed to the box, cut the other pill in two, dissolved it, added milk, and presented it to the terrier. The unfortunate creature’s tongue seemed hardly to have been moistened in it before it gave a convulsive shiver in every limb, and lay as rigid and lifeless as if it had been struck by lightning.
Sherlock Holmes drew a long breath, and wiped the perspiration from his forehead.
“I should have more faith,” he said; “I ought to know by this time that when a fact appears to be opposed to a long train of deductions, it invariably proves to be capable of bearing some other interpretation. Of the two pills in that box one was of the most deadly poison, and the other was entirely harmless. I ought to have known that before ever I saw the box at all.”