AXIOM XIII. A spirit equally diffused through the body, hastens less to escape, and consumes the body slower, than when unequally distributed. EXPLANATION. Not only an over-proportion of the spirits, with regard to the whole, shortens the duration of things: but also the same quantity less ground or broken and therefore the more spirit is comminuted, and dispersed through the finer vessels and fibres; the less it consumes. For resolution and decay always begin in the part, where the spirit is weak or wanting; and therefore exercise and frictions contribute much to long life. For all motion and agitation excellently grind, and intimately mix things together in their smallest particles. AXIOM XIV. An irregular and subsultory motion of the spirits, tends more to their escape, and proves more consuming, than a motion that is constant and equable. EXPLANATION. This axiom holds with certainty in bodies inanimate; for unequability is the parent of dis solution but in inanimate bodies it holds less strictly; because in these there is not only a consumption, but a repair to be considered: and repair depends upon the appetite of things; and appetite is sharpened by variety. But here also the axiom may be admitted so far, that this variety should rather be a regular interchange than a confusion; and as it were a constant inconconstancy. AXIOM XV. The spirit is detained in bodies of a firm and close texture, though unwillingly. EXPLANATION. All things dread a solution of their continuity; though this according to their degree of condensation or rarifaction: for the more bodies are rarefied, the lesser pores they will pass, or be driven through by compression. Hence water and air will enter where dust will not; and flame and spirit, where air and water will not. But this matter is limited; for spirit has not so strong an appetite of escaping, as to suffer too great a discontinuation; or be driven through pores that are too close and strait: and therefore if spirit be lodged in a hard body, or such a one as is unctuous, and viscous, that will not easily sepa rate, it is then withheld, imprisoned, and exerts not its appetite of escaping. Whence we see that metals and stones will not, for a very long time, let go their spirit, unless it be either excited by fire; or the grosser parts of those bodies be separated, and disjoined, by corrosive liquors. And the like holds of tenacious bodies, such as gums; only these are dissolved by a gentler heat. And therefore, robust juices of the body, a constringed skin, and the like, (which are procured by a drying aliment, exercise, and cold air), prove serviceable in prolonging life; by shutting up the pores upon the spirit, and preventing its es cape. AXIOM XVI. The spirit is willingly detained in fat and unctuous bodies; though they be not viscous. EXPLANATION. If the spirit be neither irritated by any antipathy it has to the body that surrounds it; nor fed by too great a similitude with the subject itself; nor solicited by any thing external; it be comes not very tumultuary to get out, but oily bodies want all these properties; as being not so opposite to the spirit, as hard bodies are, nor having such an affinity thereto, as aqueous ones have; nor greatly agreeing with the external air.* AXIOM XVII. Oily bodies are long preserved in a state of perfection, by a quick discharge of their aqueous mois ture. EXPLANATION. We just now observed, that aqueous moisture, as approaching nearer to the substance of the air, flies off faster than such as is oily: which has a less agreement with the air: but as both these moistures are lodged in most bodies, it happens that the aqueous betrays the oily moisture; and gradually escaping, carries that away along with itself; whence nothing is more conducive to the preservation of bodies than to dry them gently; which breathes out the watery parts, without disturbing or affecting the oily. And this not only tends to prevent corruption; as it does by consequence; but also to preserve bodies in a fresh and vigorous state. And hence it *It may be well worth considering how extensive this axiom is; and how it agrees with the ancient and later discoveries, as to the native spirits of bodies. See, in particular, the processes upon vegetables, in Boerhave's Chemis try. See also process 121. is, that gentle frictions, and moderate exercise, used so as to promote perspiration rather than sweat, greatly conduce to prolong life. AXIOM XVIII. To exclude the air from the body, contributes to longevity; if other inconveniencies be prevented. EXPLANATION. We lately observed,* that the escape of the spirit is a double action, arising from an appetite both of the air, and spirit; it is therefore of considerable service, if one of these appetites can be destroyed. This is chiefly to be expected from unctions: but the use thereof is attended with various inconveniencies: which we have endeavoured to prevent under the second of our ten operations. AXIOM XIX. By introducing juvenile spirits into an old body, the course of nature may be expeditiously put back. EXPLANATION. The spirits are like the master-wheel, that carries the other wheels round in the body: and * See axiom vii. |