This difficulty is cleared thus, that though it be true, that it hath much of the Earthy part; yet it hath also parts of Sulphur, and of quick silver, which doe open, and disopilate; neither doth it so, untill it be helped by Art, as it is ground, stirred, and made fine, in the preparing of it; the Sulphurous parts, and those of quick-silver, being thinne, active, and penetrative, they mingle, at the last with those parts, which are Earthy and astringent: Insomuch, that they being mingled after this manner one with another, we cannot now say, that the steele is astringent, but rather, that it is penetrative, attenuating and opening. Let us prove this Doctrine by Authorities; and let the first be from _Gallen_, _l. 3._ of the qualities of Simples, _c. 14._ Where, first of all he teacheth, that almost all those Medicines, which, to our sence, seeme to be _Simple_, are notwithstanding naturally _Compounded_, containing in themselves contrary qualities; and that is to say, a quality to expell, and to retaine; to incrassate, and attenuate; to rarifie, and to condense. Neither are we to wonder at it, it being understood, that in every fore-said Medicine, there is a quality to heat, and to coole; to moisten and to dry. And whatsoever Medicine it be, it hath in it, thick, and thinne parts; rare, and dense; soft, and hard. And in the fifteenth Chapter following, in the same Book, he puts an example of the Broth of a Cock, which moves the Belly; and the flesh hath the vertue to bind. He puts also the example of the _Aloes_, which if it be washt, looseth the Purgative vertue; or that which it hath, is but weake. That this differing vertue, and faculty, is found in divers substances, or parts of simple Medicaments, _Gallen_ shewes in the first Booke of his simple Medicines, and the seventeenth Chapter, bringing the example of Milke; in which, three substances are found, and separated, that is to say, the substance of Cheese, which hath the vertue to stop the Fluxe of the Belly; and the substance of Whay, which is purging; and Butter, as it is expressed in the said _Gallen_, _Cap. 15._ Also we finde in Wine which is in the Must, three substances, that is to say, earth, which is the chiefe; and a thinner substance, which is the flower, and may be called the scum, or froath: and a third substance which we properly call Wine; And every one of these substances, containes in it selfe divers qualities, and vertues; in the colour, in the smell, and in other Accidents.