Now, that through all these diversiries of Aer, Mores Hominum do Corporis temperamentum Sequi, is for the greater part so true an observation, that a Volume of Instances might be produced, if the Common notices did not sufficiently confirme it even to a Proverb. The Aer on which we continually prey, perpetually inspiring matter to the Animall and Vitall Spirits, by which they become more or lesse obfuscated, clowded and render'd obnoxious: and therefore that Prince of Physitians Hippocrates, wittily calls a sincere and pure Aer, The Internunce and Interpreter of Prudence. De Morbo Sacre. The celestiall influences being so much retarded or assisted, and improv'd through this omnipresent, and as it were, universal Medium: For, though the Aer in its simple substance cannot be vitiated; yet, in its prime qualities it suffers these infinite mutations, both from superiour and inferiour Causes, so as its accidentall effects become almost innumerable;
Let it be farther consider'd, what is most evident, That the Body feedes upon Meats commonly but at certain periods and stated times, be it twice a day or oftner; whereas, upon the Aer, or what accompanies it (est enim in ipso Aere occultus vitae cibus) it is allwaies preying sleeping, or waking; and therefore, doubtlesse the election of this constant and assiduous Food, should something concerne us; I affirme, more then even the very Meat we eat, whereof so little and indifferent nourishes and satisfies the most temperate and best Educated persons. Besides, Aer that is corrupt insinuates it self into the vital parts immediately; whereas the meats which we take though never so ill condition'd, require time for the concoction, by which its effects are greatly mitigated; whereas the other, passing so speedily to the Lungs, and virtually to the Heart it self, is deriv'd and communicated over the whole masse: In a word, as the Lucid and noble Aer, clarifies the Blood, subtilizes and excites it, cheering the Spirits and promoting digestion; so the dark, and grosse (on the Contrary) perturbs the Body, prohibits necessary Transpiration for the resolution and dissipation of ill Vapours, even to disturbance of the very Rational faculties, which the purer Aer does so far illuminate, as to have rendred some Men healthy and wise even to Miracle. And therefore the Empoysoning of Aer, was ever esteem'd no lesse fatall then the poysoning of Water or Meate it self, and forborn even amongst Barbarians; since (as is said) such Infections become more apt to insinuate themselves and
