"Those who keep gambling houses," continues the writer from whom we have just quoted, "take care to be regularly informed of everything transpiring in the city that maybe of interest to their business. You may have noticed, lounging around the most fashionable hotels, many well-dressed young men, who spend their money freely, though they have no known means of support. They are agents for gambling-houses: their business is to track the footsteps of travellers visiting New York, for business or pleasure. They worm themselves into the confidence of strangers; show them everything worth seeing in the city; and finally introduce them to their employers, the gambling-house proprietors. This hunting after wealthy strangers is systematically carried on--it is a science. These agents leave nothing to chance; they never hurry up the conclusion of the transaction. When the unwary stranger is in a fit condition for the sacrifice, they take him to the gaming table with as much indifference and coolness as butchers drive sheep to the slaughter house. These agents have a commission on the profits realized from all the customers they lead to the gaming table, and they display such ability that they seldom fail to entrap those they single out for their victims." It is a safe rule to suspect every one who approaches you with offers of friendship without being properly introduced. Shun all such society, for the hope of ruining you is all that induces the men to seek you. GAMING A NATIONAL PASSION. "There are in New York one hundred and fifty hells or gambling houses, all well known to the police, in which several millions of dollars are lost every year, by unwary persons. From time to time, police officers make a descent on the most dangerous among them, or (which is too often the case) on those whose owners have little political influence. Twenty-four hours after the descent has taken place, new gambling implements are procured in lieu of those taken away, and business is resumed as before. "Games of chance are now in vogue all over the States, and rapidly multiplying, because the thirst for sudden fortunes is everywhere on the increase. Gambling is even practised on board of those splendid steamers, that ply up and down the rivers of the country; and more than one passenger, driven distracted by his losses at the gaming table, has thrown himself overboard.