The Art of Physick
Section B. Of the 6 Non-Naturals
1. Of the Ambient Air

D. What Air is to be chosen to preserve sound Health?

C. Such as Air as is neither too fat not thick, nor misty by reason of adjoining Lakes or Rivers; but thin and serene; neither over-hot, nor over-moist, nor over-cold, nor over-dry; but temperate; not infected with the exhalations of standing Waters, common Sewers, nor Church-Yards; nor defiled with Dunghills, or other corruption and stench of things either superior or inferior, nor in a Valley surrounded with high Mountains, or in any hollow place where the Wind has no power.

D. How much Air is requisite for a man to draw?

C. Strong People, the more Breath they fetch, the better they are in health; but for weak Persons, and such are newly recovered from Sickness, to remove out of a close, into a free and open Air, is dangerous.

D. How are they then to order themselves in the use of Air?

C. They must by degrees and insensibly accustom themselves to a more free and plentiful Air.

D. When may they most safely oppose themselves to free Air?

C. Upon serene days, when the Air is neither too hot with the Sun beams, nor over-Cold, and the Wind is not too high.

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Next: Of Meat and Drink

It is interesting the term 'infected' is used for foul-smelling and putrid air; although Bacteria was unknown, the unhealthy effect of foul smelling air was long known.

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The Art Of Physick
Section A.
OF THE 7 NATURALS
(Physiology)
Introduction to the 7 Naturals
1. Elements
2. Temperaments
3. Parts
4. Humors
5. Spirits
6. Faculties
7. Actions
Section B.
OF THE 6 NOT-NATURALS
(Preservation of Health)
Introduction to the 6 Not-Naturals
1. Ambient Air
2. Food and Drink
3. Sleep and Waking
4a. Exercise &
4b. Rest
5. Excrements
6. Emotions (Passions of the Mind)
Section C.
OF THE 3 PRETER-NATURALS
(Pathology)
1. Diseases
2. Causes
3a. Symptoms &
3b. Signs