The American troops, under Quitman and Worth, had established themselves within the limits of the city, having possession of the gates of Belen and of San Cosma, but, up till nightfall, had met with a vigorous resistance from the Mexicans, led on by Santa Anna in person. They had still, apparently, a desperate task before them. It was anticipated that, with the next morning’s light, our troops would be ordered to storm the citadel, and the city of Mexico itself. When this was told to Pierce, upon his sick-bed, he rose, and attempted to dress himself; but Captain Hardcastle, who had brought the intelligence from Worth, prevailed upon him to remain in bed, and not to exhaust his scanty strength until the imminence of the occasion should require his presence. Pierce acquiesced for the time, but again arose, in the course of the night, and made his way to the trenches, where he reported himself to General Quitman, with whose division was a part of his brigade. Quitman’s share in the anticipated assault, it was supposed, owing to the position which his troops occupied, would be more perilous than that of Worth. But the last great battle had been fought. In the morning, it was discovered that the citadel had been abandoned, and that Santa Anna had withdrawn his army from the city. There never was a more gallant body of officers than those who came from civil life into the army on occasion of the Mexican War. All of them, from the rank of general downward, appear to have been animated by the spirit of young knights, in times of chivalry, when fighting for their spurs. Hitherto known only as peaceful citizens, they felt it incumbent on them, by daring and desperate valor, to prove their fitness to be intrusted with the guardianship of their country’s honor. The old and trained soldier, already distinguished on former fields, was free to be discreet as well as brave; but these untried warriors were in a different position, and therefore rushed on perils with a recklessness that found its penalty on every battle-field--not one of which was won without a grievous sacrifice of the best blood of America. In this band of gallant men, it is not too much to say, General Pierce was as distinguished for what we must term his temerity in personal exposure, as for the higher traits of leadership, wherever there was an opportunity for their display.