About the concept

Spiritus Mundi is a Latin term that means "World Spirit" and generally embodies two interpretations: the first being the spirit that gives breath to all that has been created. The second is as a source of all images and symbols as collective unconscious, or the universal memory and ‘muse’ of poetic inspiration. This last definition was coined by William Butler Yeats in his poem "The Second Coming", from his book Spiritus Mundi. The idea of Spiritus Mundi in the alchemical operation refers to the first meaning.   

On the one hand, the alchemist works to capture the most subtle matters, where the spirit of the world has not yet mixed (determined) in any of the Animalia, Vegetalia or Mineralia kingdoms; and, on the other hand, he purifies the matter with which he works in order to get again the influx of the quintessence or spirit of the world.   

This is why alchemists are seen catching the morning dew or repeatedly purifying the materials they work with by fire (by techniques such as incineration or distillation); these roads lead to the elusive Atalanta.