As the man drew up—­

“Quick!” I cried.  “You see that Greenwich car—­nearly at the Ophthalmic Hospital?  Follow it.  Don’t get too near.  I will give you further instructions through the tube.”  I leapt in.  We were off!

The rocking car ahead was rounding the bend now toward St. George’s Circus.  As it passed the clock and entered South London Road it stopped.  I raised the tube.

“Pass it slowly!”

We skirted the clock tower, and bore around to the right.  Then I drew well back in the corner of the cab.

The woman with the basket was descending!  “Pull up a few yards beyond!” I directed.  As the car re-started, and passed us, the taxi became stationary.  I peered out of the little window at the back.

The woman was returning in the direction of Waterloo Road!

“Drive slowly back along Waterloo Road,” was my next order.  “Pretend you are looking for a fare; I will keep out of sight.”

The man nodded.  It was unlikely that any one would notice the fact that the cab was engaged.

I was borne back again upon my course.  The woman kept to the right, and, once we were entered into the straight road which leads to the bridge, I again raised the speaking-tube.

“Pull up,” I said.  “On the right-hand side is an old woman carrying a basket, fifty yards ahead.  Do you see her?  Keep well behind, but don’t lose sight of her.”

The man drew up again and sat watching the figure with the basket until it was almost lost from sight.  Then slowly we resumed our way.  I would have continued the pursuit afoot now, but I feared that my quarry might again enter a vehicle.  She did not do so, however, but coming abreast of the turning in which the mysterious assault had taken place, she crossed the road and disappeared from view.

I leapt out of the cab, thrust half a crown into the man’s hand, and ran on to the corner.  The night was now far advanced, and I knew that the chances of detection were thereby increased.  But the woman seemed to have abandoned her fears, and I saw her just ahead of me walking resolutely past the lamp beyond which a short time earlier she had met with a dangerous adventure.

Since the opposite side of the street was comparatively in darkness, I slipped across, and in a state of high nervous tension pursued this strange work of espionage.  I was convinced that I had forestalled Bristol and that I was hot upon the track of those who could explain the mystery of the dead dwarf.

The woman entered the gate of the block of dwellings even more forbidding in appearance than those which that night had staged a dreadful drama.

As the figure with the basket was lost from view I crept on, and in turn entered the evil-smelling hallway.  I stepped cautiously, and standing beneath a gaslight protected by a wire frame, I congratulated myself upon having reached that point of vantage as silently as any Sioux stalker.