There was a queer little smile on Jimmie Dale’s lips, as he watched the great car swing around in the street and glide noiselessly away—­a queer little smile that still held there even after he himself had started briskly along the avenue in a downtown direction.  It was invariably the same, always the same—­the letters came unexpectedly, when least looked for, now by this means, now by that, but always in a manner that precluded the slightest possibility of tracing them to their source.  Was there anything, in his intimate surroundings, in his intimate life, that she did not know about him—­who knew absolutely nothing about her!  Benson, for instance—­that the man was absolutely trustworthy—­or else she would never for an instant have risked the letter in his possession.  Was there anything that she did not—­yes, one thing—­she did not know him in the role he was going to play to-night.  That at least was one thing that surely she did not know about him; the role in which, many times, for weeks on end, he had devoted himself body and soul in an attempt to solve the mystery with which she surrounded herself; the role, too, that often enough had been a bulwark of safety to him when hard pressed by the police; the role out of which he had so carefully, so painstakingly created a now recognised and well-known character of the underworld—­the role of Larry the Bat.

Jimmie Dale turned from Fifth Avenue into Broadway, continued on down Broadway, across to the Bowery, kept along the Bowery for several more blocks—­and finally headed east into the dimly lighted cross street on which the Sanctuary was located.

And now Jimmie Dale became cautious in his movements.  As he approached the black alleyway that flanked the miserable tenement, he glanced sharply behind and about him; and, at the alleyway itself, without pause, but with a curious lightning-like side step, no longer Jimmie Dale now, but the Gray Seal, he disappeared from the street, and was lost in the deep shadows of the building.

In a moment he was at the side door, listening for any sound from within—­none had ever seen or met the lodger or the first floor either ascending or descending, except in the familiar character of Larry the Bat.  He opened the door, closed it behind him, and in the utter blackness went noiselessly up the stairs—­stairs so rickety that it seemed a mouse’s tread alone would have set them creaking.  There seemed an art in the play of Jimmie Dale’s every muscle; in the movements, lithe, balanced, quick, absolutely silent.  On the first landing he stopped before another door, there was the faint click of a key turning in the lock; and then this door, too, closed behind him.  Sounded the faint click of the key as it turned again, and Jimmie Dale drew a long breath, stepped across the room to assure himself that the window blind was down, and lighted the gas jet.

A yellow, murky flame spurted up, pitifully weak, almost as though it were ashamed of its disreputable surroundings.  Dirt, disorder, squalour, the evidence of low living testified eloquently enough to any one, the police, for instance, in times past inquisitive until they were fatuously content with the belief that they knew the occupant for what he was, that the place was quite in keeping with its tenant, a mute prototype, as it were, of Larry the Bat, the dope fiend.