“Give them here,” said Holmes. “Now, Doctor,” turning to me, “are those ordinary pills?”

They certainly were not. They were of a pearly grey colour, small, round, and almost transparent against the light. “From their lightness and transparency, I should imagine that they are soluble in water,” I remarked.

“Precisely so,” answered Holmes. “Now would you mind going down and fetching that poor little devil of a terrier which has been bad so long, and which the landlady wanted you to put out of its pain yesterday.”

I went downstairs and carried the dog upstairs in my arms. Its laboured breathing and glazing eye showed that it was not far from its end. Indeed, its snow-white muzzle proclaimed that it had already exceeded the usual term of canine existence. I placed it upon a cushion on the rug.