IT was growing dark, and the evening was very cold. The lamps were lit, and the streets were filled with an eager throng hurrying homeward--Baltimore always presents a busy scene at dark, as people of all classes and ages throng its streets, returning from their daily avocations. The merchant and the mechanic, the professional man and the street laborer, the idler and the man of business, the millionaire and the beggar, the sewing girl and the lady of fashion, representatives of all classes, colors and nations under the sun, fill the streets, hurrying on as if their lives depended upon their speed; jostling each other unceremoniously, and filling the air with the sound of their voices. I have often stood upon the street at the hour of twilight, and watched the scene before me with intense interest. One sees human nature in all its forms, on the thoroughfares of Baltimore at this hour.