Now, as I have pointed out already, the central theorem of mystical theology is, in Christian terminology, that of the regeneration of the soul by the Spirit of CHRIST. The corresponding process in alchemy is that of the transmutation of the "base" metals into silver and gold by the agency of the Philosopher's Stone. Merely to remove the evil sulphur of the "base" metals, thought the alchemists, though necessary, is not sufficient to transmute them into "noble" metals; a maturing process is essential, similar to that which they supposed was effected in Nature's womb. Mystical theology teaches that the powers and life of the soul are not inherent in it, but are given by the free grace of God. Neither, according to the alchemists, are the powers and life of nature in herself, but in that immanent spirit, the Soul of the World, that animates her. As writes the famous alchemist who adopted the pleasing pseudonym of "BASIL VALENTINE" (_c_. 1600), "the power of growth... is imparted not by the earth, but by the life-giving spirit that is in it. If the earth were deserted by this spirit, it would be dead, and no longer able to afford nourishment to anything. For its sulphur or richness would lack the quickening spirit without which there can be neither life nor growth."(1a) To perfect the metals, therefore, the alchemists argued, from analogy with mystical theology, which teaches that men can be regenerated only by the power of CHRIST within the soul, that it is necessary to subject them to the action of this world-spirit, this one essence underlying all the varied powers of nature, this One Thing from which "all things were produced... by adaption, and which is the cause of all perfection throughout the whole world."(2a) "This," writes one alchemist, "is the Spirit of Truth, which the world cannot comprehend without the interposition of the Holy Ghost, or without the instruction of those who know it. The same is of a mysterious nature, wondrous strength, boundless power.... By Avicenna this Spirit is named the Soul of the World. For, as the Soul moves all the limbs of the Body, so also does this Spirit move all bodies. And as the Soul is in all the limbs of the Body, so also is this Spirit in all elementary created things. It is sought by many and found by few. It is beheld from afar and found near; for it exists in every thing, in every place, and at all times. It has the powers of all creatures; its action is found in all elements, and the qualities of all things are therein, even in the highest perfection... it heals all dead and living bodies without other medicine... converts all metallic bodies into gold, and there is nothing like unto it under Heaven."(1b) It was this Spirit, concentrated in all its potency in a suitable material form, which the alchemists sought under the name of "the Philosopher's Stone". Now, mystical theology teaches that the Spirit of CHRIST, by which alone the soul of man can be