De Origine Morborum Invisibilium  

"Another class consists of the Incubi and Succubi, of which rabbinical traditions speak in an allegorical manner as having been created by the spilling of the seed of Adam (the animal man) while engaged with Lilith, his first wife (meaning a morbid imagination). Paracelsus says in his book, "De Origine Morborum Invisibilium," lib. iii : "Imagination is the cause of Incubi and Succubi and fluidic Larvae. The Incubi are male and the Succubi female beings. Tbey are the outgrowths of an intense and lewd imagination of men or women, and after they take form they are carried away. They are formed of the sperma found in the imagination of those who commit the unnatural sin of Onan in thought and desire. Coming as it does from the imagination alone, it is no true sperma, but only a corrupted salt (essence). Only a seed that enters the organs which Nature provided for its development can grow into a body. If seed is not planted into the proper soil it will rot. If sperma does not come into the proper matrix it will not produce anything good, but something useless. Therefore the Incubi and Succubi grown out of corrupted seed, without the natural order of things, are evil and useless ; and Thomas of Aquinas has made an error by mistaking such a useless thing for a complete one."-- The Life and the Doctrines of Philippus Theophrastus Bombast of Hohenheim Known as Paracelsus by Franz Hartmann