If, then, sound health is the foundation of success and happiness in life, how important it is that we should study the laws of health, which is but another expression for the laws of nature! The closer we keep to the laws of nature the nearer we are to good health, and yet how many persons there are who pay no attention to natural laws, but absolutely transgress them, even against their own natural inclination. We ought to know that the "sin of ignorance" is never winked at in regard to the violation of nature's laws; their infraction always brings the penalty. A child may thrust its finger into the flames without knowing it will burn, and so suffers; repentance, even, will not stop the smart. Many of our ancestors knew very little about the principle of ventilation. They did not know much about oxygen, whatever other "gin" they might have been acquainted with; and consequently, they built their houses with little seven-by-nine feet bedrooms, and these good old pious Puritans would lock themselves up in one of these cells, say their prayers and go to bed. In the morning they would devoutly return thanks for the "preservation of their lives" during the night, and nobody had better reason to be thankful. Probably some big crack in the window, or in the door, let in a little fresh air, and thus saved them. Many persons knowingly violate the laws of nature against their better impulses, for the sake of fashion. For instance, there is one thing that nothing living except a vile worm ever naturally loved, and that is tobacco; yet how many persons there are who deliberately train an unnatural appetite, and overcome this implanted aversion for tobacco, to such a degree that they get to love it. They have got hold of a poisonous, filthy weed, or rather that takes a firm hold of them. Here are married men who run about spitting tobacco-juice on the carpet and floors, and sometimes even upon their wives besides. They do not kick their wives out-of-doors like drunken men, but their wives, I have no doubt, often wish they were outside of the house. Another perilous feature is that this artificial appetite, like jealousy, "grows by what it feeds on;" when you love that which is unnatural, a stronger appetite is created for the hurtful thing than the natural desire for what is harmless. There is an old proverb which says that "habit is second nature," but an artificial habit is stronger than nature. Take, for instance, an old tobacco-chewer; his love for the "quid" is stronger than his love for any particular kind of food. He can give up roast beef easier than give up the weed.