The New-York of 1851 resembles her of fifty years ago scarcely more than the West End of London resembles Birmingham or Bristol. In 1800, one might easily believe the old story, that the streets were originally laid out by the cows, as they went out to pasture and returned at evening. Streets running in all sorts of curves crossed each other at all conceivable angles, making a maze without a plan, through which strangers needed to drop beans, like the children in the fairy-tale, to avoid being wholly lost. Fortunately, the city is not very wide, so that Broadway, which always ran lengthwise through the centre, has served as a tolerable clue from the beginning. Great sacrifices have been made for the sake of regularity, and there is now a tolerable degree of it, even in the old, or south part of the city, cross streets running from Broadway to either river with an approach to parallelism. In the early time, the town presented no bad resemblance in shape to the phenomenon called a "mackerel sky," Broadway representing the spine, and the streets running to either river the ribs, while northward and southward was a tapering off; on the south, where the Battery juts into the bay, and on the north, where the uppermost houses gradually narrowed till Broadway came to an end, with few buildings on either side of it. But in these later days, when Knickerbocker limits no longer confine the heterogeneous thousands that have pushed the old race from their stools, sixteen great avenues, each a hundred feet wide, run parallel with Broadway and the rivers, cut at right angles by wide streets, lined with costly dwellings, churches, schools, and other edifices. As is usual in great commercial towns, the lowest portion of the population haunt the neighborhood of the wharfs; and, in New-York, the eastern side of the city in particular attracts this class. But, perhaps, no city of the size has fewer streets of squalid poverty, although the encouragement given to immigration is such that there must necessarily be great numbers of wretched immigrants who have neither the will nor the power to live by honest industry. It is in truth for this class of persons that hospitals and penitentiaries are here built, foreigners supplying at least nine-tenths of the inmates of those institutions in New-York. As to clean and healthy streets, the upper and newer part of the city has, of course, the advantage. It is laid out with special attention to drainage, for which the ridged shape of the ground affords great facility; the island on which New-York is built being highest in the middle, and sloping off, east and west, towards the Hudson and East Rivers.