CONCERNING THE NATURE OF THINGS.
BOOK III.
Concerning the Preservation of Natural Things.
IN order that a thing may be preserved and defended from injury, it is necessary that first of all its enemy should be known, so that it may be shielded therefrom, and that it may not be hurt or corrupted by it, in its substance, virtue, force, or in any other way suffer loss. A good deal depends upon this, then, that the enemy of all natural things should be recognised; for who can guard himself against loss and adverse chance if he is ignorant of his enemy? Surely, no one. It is therefore necessary that such enemy should be known. There are many enemies; and it is just as necessary to know the bad as the good. Who, in fact, can know the good without a knowledge of the evil? No one. No one who has never been sick knows how great a treasure health is. Who knows what joy is, that was never sad or sorrowful? And who knows rightly about what God is, who knows nothing about the devil? Wherefore since God has made known to us the enemy of our soul, that is, the devil, He also points out to us the enemy of our life, that is, death, which is the enemy of our body, of our health, the enemy of medicine, and of all natural things. He has made known this enemy to us and also how and by what means we must escape him. For as there is no disease against which there has not been created and discovered a medicine which cures and drives it away, so there is always one thing placed over against another—one water over against another, one stone over against another, one mineral over against another, one poison over against another, one metal over against another—and the same in many other matters, all of which it is not necessary to recount here.
But it ought to be known how, and by what means, each several thing is preserved and guarded from loss: that many things, for instance, have to be kept for a long time in the earth. All roots, especially, remain for a long while in the earth fruitful and uncorrupted. In like manner, herbs and flowers and all fruits keep undecayed and green in water. So also many other fruits, and especially apples, can be preserved in water, and protected from every decay, until new apples are produced.
So also flesh and blood, which very soon putrefy and become rancid, can be kept in cold spring water; and not only so, but by the co-optation of renewed and fresh spring water they can be transmuted into a quintessence,
