At last he found it, situated at the back of one of the shelves, and set above a row of four small books, so that it could readily be reached by inserting the hand.

He flooded the place with light; and perceived at a glance that a length of white flex crossing the ceiling enabled anyone seated at the table to ignite the lamp from there also.  Then, replacing his torch in his pocket, and assuring himself that the iron bar lay within easy reach, he began deliberately to remove all of the books from the shelves covering that side of the room upon which the switch was situated.  His theory was a sound one; he argued that the natural and proper place for such a switch in such a room would be immediately inside the door, so that one entering could ignite the lamp without having to grope in the darkness.  He was encouraged, furthermore, by the fact that at a point some four feet to the left of this switch there was a gap in the bookcases, running from floor to ceiling; a gap no more than four inches across.

Having removed every book from its position, save three, which occupied a shelf on a level with his shoulder and adjoining the gap, he desisted wearily, for many of the volumes were weighty, and the heat of the room was almost insufferable.  He dropped with a sigh upon a silk ottoman close beside him....

A short, staccato, muffled report split the heavy silence... and a little round hole appeared in the woodwork of the book-shelf before which, an instant earlier, M. Max had been standing—­in the woodwork of that shelf, which had been upon a level with his head.

In one giant leap he hurled himself across the room—... as a second bullet pierced the yellow silk of the ottoman.

Close under the trap he crouched, staring up, fearful-eyed....

A yellow hand and arm—­a hand and arm of great nervous strength and of the hue of old ivory, directed a pistol through the opening above him.  As he leaped, the hand was depressed with a lightning movement, but, lunging suddenly upward, Max seized the barrel of the pistol, and with a powerful wrench, twisted it from the grasp of the yellow hand.  It was his own Browning!

At the time—­in that moment of intense nervous excitement—­he ascribed his sensations to his swift bout with Death—­with Death who almost had conquered; but later, even now, as he wrenched the weapon into his grasp, he wondered if physical fear could wholly account for the sickening revulsion which held him back from that rectangular opening in the bookcase.  He thought that he recognized in this a kindred horror—­as distinct from terror—­to that which had come to him with the odor of roses through this very trap, upon the night of his first visit to the catacombs of Ho-Pin.

It was not as the fear which one has of a dangerous wild beast, but as the loathing which is inspired by a thing diseased, leprous, contagious....

A mighty effort of will was called for, but he managed to achieve it.  He drew himself upright, breathing very rapidly, and looked through into the room—­the room which he had occupied, and from which a moment ago the murderous yellow hand had protruded.