The sick or weakly have, more than others, need of a good air; it is a remedy that acts, and perhaps the only one that does so, without the concurrence of our nature’s vital forces, to which it gives no trouble, and is no draught upon them: and for that very reason, it is of the greatest importance not to neglect it. That air which is the properest for a general atony or relaxation, is a dry, temperate air: too moist, or too hot an air are pernicious. I know one labouring under a disorder of this kind, whom great heats throw into a total faintness or exhaustion of strength, and whose state of health varies in summer, according to the vicissitudes of days less hot or less cold. A cold air is much less to be dreaded; and it is necessarily, and according to Nature, that it should be so. Heat relaxes still more the fibres which are already but too relaxed, and dissolves still more the humors already too much dissolved: Cold, on the contrary, is a remedy against these two evils. When the Caribes are attacked with the palsy, after, and in consequence of those dreadful convulsions of the cholic, to which they are subject, when they cannot be sent to the warm-baths in the north of Jamaica, the other expedient is to send them to some place of a colder air than that of their country; and this bare change of air has always manifestly a favorable effect. Another essential quality of the air, is, that it should not be impregnated with noxious particles: that it should not have lost, by its stay or stagnation in inhabited places, that kind of reviving quality which constitutes all its efficacy, and which might be called its vital spirit as necessary to plants as to animals; and such is the air one breathes in a country, open, airy, interspersed with the verdure of herbs, bushes, and trees. “Let the sick, says ARETÆUS[104], live near meadows, fountains, rivulets; the freshness they exhale, and the gaiety which those objects inspire, fortify the mind, restore strength to the body, and give new life.” The air of the town, continually sucked in and let out again, continually crouded with foul vapors or infected exhalations, combines at once the two inconveniences of possessing less of that vital spirit, and of being big with noxious particles. On the other hand, the air of the country is enriched with the two opposite qualities. It is a pure virgin air, an air impregnated with all that is the most volatile, the most agreeable, the most cordial, in the effluvia of the plants, and in the vapor of the earth, which is itself very salubrious.