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.