Sometimes a yellow face showed close to one of the streaming windows; sometimes a black-eyed, pallid face, but never a face wholly sane and healthy.  This was an underworld where squalor and vice went hand in hand through the beautiless streets, a melting-pot of the world’s outcasts; this was the shadowland, which last night had swallowed up Nayland Smith.

Ceaselessly I peered to right and left, searching amid that rain-soaked company for any face known to me.  Whom I expected to find there, I know not, but I should have counted it no matter for surprise had I detected amid that ungracious ugliness the beautiful face of Karamaneh the Eastern slave-girl, the leering yellow face of a Burmese dacoit, the gaunt, bronzed features of Nayland Smith; a hundred times I almost believed that I had seen the ruddy countenance of Inspector Weymouth, and once (at which instant my heart seemed to stand still) I suffered from the singular delusion that the oblique green eyes of Dr. Fu-Manchu peered out from the shadows between two stalls.

It was mere phantasy, of course, the sick imaginings of a mind overwrought.  I had not slept and had scarcely tasted food for more than thirty hours; for, following up a faint clue supplied by Burke, Slattin’s man, and, like his master, an ex-officer of New York Police, my friend, Nayland Smith, on the previous evening had set out in quest of some obscene den where the man called Shen-Yan—­former keeper of an opium-shop—­was now said to be in hiding.

Shen-Yan we knew to be a creature of the Chinese doctor, and only a most urgent call had prevented me from joining Smith upon this promising, though hazardous expedition.

At any rate, Fate willing it so, he had gone without me; and now—­although Inspector Weymouth, assisted by a number of C. I. D. men, was sweeping the district about me—­to the time of my departure nothing whatever had been heard of Smith.  The ordeal of waiting finally had proved too great to be borne.  With no definite idea of what I proposed to do, I had thrown myself into the search, filled with such dreadful apprehensions as I hope never again to experience.

I did not know the exact situation of the place to which Smith was gone, for owing to the urgent case which I have mentioned, I had been absent at the time of his departure; nor could Scotland Yard enlighten me upon this point.  Weymouth was in charge of the case—­under Smith’s direction—­and since the inspector had left the Yard, early that morning, he had disappeared as completely as Smith, no report having been received from him.

As my driver turned into the black mouth of a narrow, ill-lighted street, and the glare and clamor of the greater thoroughfare died behind me, I sank into the corner of the cab burdened with such a sense of desolation as mercifully comes but rarely.

We were heading now for that strange settlement off the West India Dock Road, which, bounded by Limehouse Causeway and Pennyfields, and narrowly confined within four streets, composes an unique Chinatown, a miniature of that at Liverpool, and of the greater one in San Francisco.  Inspired with an idea which promised hopefully, I raised the speaking tube.