mention my destination to Thorndyke. But this failed to explain the
mystery, since I had mentioned no address beyond "Kensington." I had,
indeed, mentioned the name of Mrs. Hornby, but the supposition that my
friends might be known by name to Mrs. Schallibaum, or even that she
might have looked the name up in the directory, presented a probability
too remote to be worth entertaining.

But, if I reached no satisfactory conclusion, my cogitations had one
useful effect; they occupied my mind to the exclusion of that
unfortunate draught of tea. Not that I had been seriously uneasy after
the first shock. The quantity that I had swallowed was not large--the
tea being hotter than I cared for--and I remembered that, when I had
thrown out the lump of sugar, I had turned the cup upside down on the
table; so there could have been nothing solid left in it. And the lump
of sugar was in itself reassuring, for it certainly would not have been
used in conjunction with any less conspicuous but more incriminating
form of poison. That lump of sugar was now in my pocket, reserved for
careful examination at my leisure; and I reflected with a faint grin
that it would be a little disconcerting if it should turn out to
contain nothing but sugar after all.

On leaving the tea-shop, I walked up Sloane Street with the intention of
doing what I ought to have done earlier in the day. I was going to make
perfectly sure that no spy was dogging my footsteps. But for my
ridiculous confidence I could have done so quite easily before going to
Endsley Gardens; and now, made wiser by a startling experience, I
proceeded with systematic care. It was still broad daylight--for the
lamps in the tea-shop had been rendered necessary only by the faulty
construction of the premises and the dullness of the afternoon--and in
an open space I could see far enough for complete safety. Arriving at
the top of Sloane Street, I crossed Knightsbridge, and, entering Hyde
Park, struck out towards the Serpentine. Passing along the eastern
shore, I entered one of the long paths that lead towards the Marble Arch
and strode along it at such a pace as would make it necessary for any
pursuer to hurry in order to keep me in sight. Half-way across the great
stretch of turf, I halted for a few moments and noted the few people who
were coming in my direction. Then I turned sharply to the left and
headed straight for the Victoria Gate, but again, half-way, I turned off
among a clump of