the bottom of the tea-cup lay a single lump of sugar. To the majority of persons it would have meant nothing. They would have assumed that they had dropped it in and forgotten it and would have proceeded to pour out the tea. 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. As I returned her intent look—which I could do unobserved, since my face, reflected in the mirror, was in deep shadow—I suddenly perceived that that steady gaze engaged her right eye only; the other eye was looking sharply towards her left shoulder. In short, she had a divergent squint of the left eye.
I put down my cup with a thrill of amazement and a sudden surging up of suspicion and alarm.
