Parcelsus maintained the existence of four Aristotelian elements: air, water, fire, earth..Every one had a symbolic meaning in the creation of substances and characters. AIR corresponded to irascible temper, WATER to calm temper, FIRE to sanguine temper, EARTH to melancholy, the "dark temper". Parcelsus also considered the presence of three alchemistical principles (salt, sulphur, mercury) to explain material mutation: he called them "matrices", "archetypes", "fluids". They simply consisted of spiritual characteristics inside bodies. In fact SALT corresponded to "the body", SULPHUR to "the soul", MERCURY to "the spirit". His theory was successful and had many followers. Later Parcelsus discovered the 5th Essence also called Celestial Water, produced by the phenomenon of guttation and used in alchemistical practises. It is a matter of special drops formed on the leaves of a particular plant, Alchemilla vulgaris. Today it is certified that Alchemilla sp. can be used as a pain-killer, because it contains salicylic acid.