But it happened that, at this time, I did not take sugar in my tea; whence it followed that the lump had not been put in by me.

Assuming, therefore, that it had been carelessly dropped in by the waitress, I turned it out on the table, filled the cup, added the milk, and took a tentative draught to test the temperature.
The cup was yet at my lips when I chanced to look into the mirror that faced my table.

Of course it reflected the part of the shop that was behind me, including the cashier's desk; at which the owner of the basket now stood paying for her refreshment.

Between her and me was a gas chandelier which cast its light on my back but full on her face; and her veil notwithstanding, I could see that she was looking at me steadily; was, in fact, watching me intently and with a very curious expression--an expression of expectancy mingled with alarm.

But this was not all.