§ =24.= The mystical as distinguished from the pseudo-practical descriptions of the Stone and its preparation are by far the more interesting of the two. Paracelsus, in his work on _The Tincture of the Philosophers_, tells us that all that is necessary for us to do is to mix and coagulate the “rose-coloured blood from the Lion” and “the gluten from the Eagle,” by which he probably meant that we must combine “philosophical sulphur” with “philosophical mercury.” This opinion, that the Philosopher’s Stone consists of “philosophical sulphur and mercury” combined so as to constitute a perfect unity, was commonly held by the alchemists, and they frequently likened this union to the conjunction of the sexes in marriage. “Eirenæus Philalethes” tells us that for the preparation of the Stone it is necessary to extract the seed of gold, though this cannot be accomplished by subjecting gold to corrosive liquids, but only by a homogeneous water (or liquid)--the Mercury of the Sages. In the _Book of the Revelation of Hermes, interpreted by Theophrastus Paracelsus, concerning the Supreme Secret of the World_, the Medicine, which is here, as not infrequently, identified with the alchemistic essence of all things or Soul of the World, is described in the following suggestive language: “This 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.”[36] [36] See BENEDICTUS FIGULUS: _A Golden and Blessed Casket of Nature’s Marvels_ (translated by A. E. Waite, 1893, pp. 36, 37, and 41). The Theory of Development.