To this end, it is, in the first place, necessary to be careful in preserving health--for, in sickness, the imagination is disturbed; and disagreeable, sometimes terrible ideas are apt to present themselves. But for health, our main dependence is on EXERCISE and TEMPERANCE. These render the appetite sharp, the digestion easy, the body lightsome, and the temper cheerful, with sweet sleep and pleasant dreams. While indolence and full feeding never fail to bring on loaded stomachs, with night-mares and horrors--we fall from precipices--are stung by serpents--assaulted by wild beasts--murderers--devils--with all the black train of unimaginable danger and wo. Temperance, then, is all-important to sweet sleep and pleasant dreaming. But a main point of temperance, is to _shun hearty suppers_, which are indeed not safe, even when dinner has been missed; what then must be the consequence of hearty suppers after full dinners? why only restless nights and frightful dreams; and sometimes _a stroke of the apoplexy_, after which they sleep till doomsday. The newspapers often relate instances of persons, who, after eating hearty suppers, are found dead in their beds next morning. Another grand mean of preserving health, is to admit a constant supply of _fresh air_ into your chamber. A more sad mistake was never committed than that of sleeping in tight rooms, and beds closely curtained. This has arisen from the dread of night air. But, after all the clamour and abuse that have been heaped on _night air_, it is very certain that no outward air, that may come in, is half so unwholesome as the air often breathed in a close chamber. As boiling water does not grow hotter by longer boiling, if the particles that receive greater heat can escape; so living bodies do not putrify, if the particles, as fast as they become putrid, can be thrown off. Nature expels them by the pores of the skin and lungs, and in a free open air they are carried off; but, in a _close room_, we receive them again and again, though they become more and more corrupt. A number of persons crowded into a small room, thus spoil the air in a few minutes, and even render it mortal, as in the black hole at Calcutta.[3] A single person is said to spoil a gallon of air per minute, and therefore requires a longer time to spoil a chamber full; but it is done, however, in proportion, and many putrid disorders hence have their origin. It is recorded of Methusalem, who, being the longest liver, may be supposed to have best preserved his health, that he slept always in the open air; for when he had lived five hundred years, an angel said to him, "_arise, Methusalem, and build thee an house, for thou shalt live yet five hundred years longer_." But Methusalem answered and said, "_If I am to live but five hundred years longer, it is not worth while to build me an house--I will sleep in the air, as I have been used to do._" Physicians, after having for