I saw her hurriedly withdraw her head and hide herself behind the curtain, from which position she watched him as with tired steps and somewhat dejected mien, he passed up the steps and entered the house. Not till the door closed upon him, did she venture to issue forth and with a hurried movement shut the blinds and disappear. This anxiety on her part redoubled mine, and thankful enough was I when on the next day I found myself well enough to renew my operations. To ferret out this mystery, if mystery it was,--I still found myself forced to admit the possibility of there being none--had now become the one ambition of my life; and all because it was not only an unusually blind one, but of a nature that involved danger to my position as detective, I entered upon it with a zest rare even to me who love my work and all it involves with an undivided passion.To equip myself, then, in a fresh disguise and to join Mr. Blake shortly after he had left his own corner, was anything but a hardship to me that bright winter morning, though I knew from past experience, a long and wearisome walk was before me with nothing in all probability at the end but reiterated disappointment. But for once the fates had willed it otherwise. Whether Mr. Blake, discouraged at the failure of his own attempts, whatever they were, felt less heart to prosecute them than usual I cannot say, but we had scarcely entered upon the lower end of the Bowery, before he suddenly turned with a look of disgust, and gazing hurriedly about him, hailed a Madison Avenue car that was rapidly approaching. I was at that moment on the other side of the way, but I hurried forward too, and signaled the same car. But just as I was on the point of entering it I perceived Mr. Blake step hastily back and with his eyes upon a girl that was hurrying past him with a basket on her arm, regain the sidewalk with a swiftness that argued his desire to stop her. Of course I let the car pass me, though I did not dare approach him too closely after my late conspicuous attempt to enter it with him. But from my stand on the opposite curb-stone I saw him draw aside the girl, who from her garments might have been the daughter or wife of any one of the shiftless, drinking wretches lounging about on the four corners within my view, and after talking earnestly with her for a few moments, saunter at her side down Broome Street, still talking. Reckless at this sight of the consequences which might follow his detection of the part I was playing, I hasted after them, when I was suddenly disconcerted by observing him hurriedly separate from the girl and turn towards me with intention as it were to regain the corner he had left. Weighing in an instant the probable good to be obtained by following either party, I determined to leave