'breathe not the chaos of eternal smoke,
'and volatile corruption, from the dead,
'the dying, sick'ning, and the living world
'exhaled, to sully heaven's transparent dome
'with dim mortality.

'While yet you breathe, away; the rural wilds
'invite; the mountains call you, and the vales;
'the woods, the streams, and each ambrosial breeze
'that fans the ever undulating sky.'

But there are many whose occupations oblige them to reside in large
towns; they, therefore, should make frequent excursions into the
country, or to such situations as will enable them to enjoy, and to
breathe air of a little more purity. I say _enjoy_, for who that has
been for some time shut up in the town, without breathing the pure
air of the country, does not feel his spirits revived the moment he
emerges from the azote of the town. Let not therefore, if possible,
a single day pass, without enjoying, if but for an hour, the pure
air of the country. Doing this, only for a short time _every_ day,
would be much more effectual than spending whole days, or even weeks
in the country, and then returning into the corrupt atmosphere of
the town; for when you have for a long time breathed an impure air,
the excitability becomes so morbidly accumulated, from the want of
the stimulus of pure air, that the air of the country will have too
great an effect upon you; it will frequently, in the course of a day
or two, bring on an inflammatory fever, attended with stuffing of
the nose, hoarseness, a great degree of heat, and dryness of the
skin, with other symptoms of a violent cold.