NIGHT ATR.
| ID dEOIu 6ApOSuTe to ulStI aITs IS at al times precaution of very great import

 ance, to those who covet continuance O.

 health but perhaps never more so than al

 the present season of the year. (Sept.)

 The very great difference which now prevails between the temperature of the day and that of the night, the injurious ef- fleets of which inequality are increased by the large amount of moisture that is pre- cipitated towards the earth after sunset, in the form of dew, renders the imprudent ex- posture of the body at night to the external air, very fruitful source of disease.

 But it is not merely from the system be- ing subjected to the influence ofa cool and damp atmosphere, during exposure on an autumnal night, that bad effects are to be apprehended. There is still another cause of disease, prevalent in particular situa- lions; the influence of which is much more active after sunset than during the day. We allude to bad or impure air-the mala- ri0 of Italian writers.

 In low, wet, or marshy districts, in the neighborhood of extensive collections of stagnant water, along the course of rivers, upon the wharves of a commercial city, or, indeed, in every situation where a consid- erable amount of animal and vegetable sub- stances, or filth of any kind, is allowed to accumulate and undergo decomposition, there is generated during the day a certain deleterions principle which, combined with the atmosphere, impairs it's purity and wholesomeness or when in considerable amount, renders it totally unfit for the sup- port life. Under ordinary circumstances, this deletcrious principle being diffused du- ring the day over large extent of the att mosphere, however much it may impair the health and vigour of the system and undermine the constitution, is seldom suf- 6ciently concentrated to produce, at once, disease. After night, however, when, in consequence of diminished heat, the watcry vapours contained in the atmosphere be- come condensed and descend, they carry with them the impurities floating in the latter, which in this manner are caused to accumulate in the immediate vicinity of the earth-communicating disease of the most malignant and fatal character to all who may chance to be exposed to their in- fuence.

 So much and SO justly dreaded is the evening dew in Italy, and particularly in the neighborhood of Rome, where the Pontine marshes constitute an immense la boratory for the production of malaria, that the inhabitants shut themselves up in their houses on the decline of day-never going abroad, unless compelled by absolute necessity, after sunset in the evening, nor before sunrise in the morning. The same precaution to avoid the damp and coolness of the night, experience has taught to eve ry people who reside in situations where intermittent levers prevail, or in warm and tropical regions, where the heat of the day is sufficient to develope the dreaded mala- ria, by which the bilious, yellow, and other malignant levers are produced.

 The prcjudicial effects of the night air will more certainly be experienced by the system during sleep, than during state of wakeiulness. Instances have indeed oc- cured of individuals lying down to sleep at night in the Campagna, near Rome, and being found dead in the morning. Very few at least, escape an attack of dis ease who have the imprudence to fall a. sleep exposed to the open air in an unheal- thy district. Thus, history records many examples of the finest armies being de- stroyed, and the progress of tho conqueror completely arrested by encamping for a single night, without sufficient shelter, in such situation.

 Though, in our own country, it is only in the most unhealthy districts 1.-the south. that effects such as these are to be feared yet the chilly and humid state of the night air. independent of various causes, which, in all situations, tend to produce in it more or less of impurity, is sufficient reason why it should be carefully avoided by all who would preserve their systems from disease. .-.. It is not merely, however. from expo sure out of doors, or from sleeping on the bare ground without shelter of any kind that injury to health is to be anticipated at ter night-it may, likewise, and with near ly the same certainty, be incurred by sit

 ting opposite an open windowssor in cur rent of air admitted from without, or sl'l

 more surely by sleeping in either of tbes' situations. Hence, the practice puisuet by the inhabitants of Rome, of closing care

 fully their houses before sunset, is ont l which, at this season Of the year, should b. adopted by those who reside in situation

 where there is any danger of the air beini impure : even in those cities or location

 which are comparatively healthy, we ar'