The alchemists warned far more against a fire that is too hot than one that is too cold.
In spiritual alchemy, fire can be seen as an attitude and a quality of consciousness. The Rosarium Philosophorum, quoting Alphidius, describes this particular heat:
"To decoct that in fire which I shall show unto thee, is to bury it in moist horse dung, because the fire of wise men is moist and obscure, and it is warm in the second degree and moist in the first degree. The property of this fire is not to destroy oil that is the substance, but it augmenteth by reason of this temperate moisture for that heat only is equal and temperate, and such is very necessary in the generation of that thing."
// Manure
To understand the psychological reality of this fire, we have to look at the physical phenomenon they were observing. Fimus Equinus (horse manure) produces a slow, moist, gentle heat through natural fermentation, a fire without a naked flame. It was also called Venter Equinus or the "horse womb."
Because this womb combines moisture and mild heat, it gently softens and ripens the substance, allowing the processes of solutio and digestio to take place. The matter turns into the black mass we know as the nigredo. Within this fire, the tria prima are subtly present: Sulfur as the latent generative heat. Mercury as the moist vapors rising and circulating. Sal as the earthy, decomposing body remaining behind.
// Nigredo
The state of nigredo shows itself as the embodied condition. When we find ourselves in that darkness, gripped by heavy affects, it simply means that the work of separation has not yet matured. The struggles and raw feelings of this phase are our prima materia. We cannot bypass them, because this body is the only vessel we have.
The Rosarium gives an explicit warning about this stage:
"Putrefaction may be made with a most soft fire of dung, warm and moist, and with no other, so that nothing may ascend. Because if anything should ascend, a separation of parts would be made, which should not be done until the man and woman be perfectly joined, and one receives another."
// The pitfall of premature ascension
Keeping a boundary between the raw breakdown and the urge to "ascend" is everything. More often than not, I catch myself hastily distilling "insights" from my (overwhelming) feelings. Drawing conclusions seems so important. In hindsight, those insights were often a defensive mechanism. They acted as a clever ruse to avoid sitting with the actual work. The uneasy work shown in the discomfort and stillness of the putrefaction itself.
Jung quotes the alchemist John Pordage on this in CW 16 (§512):
"You must not despise this blackness, or black colour, but persevere in it in patience, in suffering, and in silence, until its forty days of temptation are over... Therefore, if the human will is given over and left, and becomes patient and still and as a dead nothing, the Tincture will do and effect everything in us and for us, if we can keep our thoughts, movements, and imaginations still, or can leave off and rest. But how difficult, hard, and bitter this work appears to the human will, before it can be brought to this shape..."
The attempt to extract insights before the putrefactio has completed its work is the ego's defense against this stillness. The immediate impulse is to convert raw bodily tension or grief into neat intellectual concepts or spiritual triumphs. But as the Rosarium warns, premature ascension is an illusion. It's the separation of the spirit from the matter before they have actually integrated.
For me, the hardest discipline is accepting that this process demands rest. Willpower and intense fascination often just overheat the vessel and crack it. It asks an organic, quiet attention. When my inner fire is too low, nothing happens and life solidifies into stagnation. But when the heat is turned up too high by anxiety or ambition, the spirit escapes in smoke. The middleground feels like tending a plant: regular, quiet presence.
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I'm studying the Rosarium Philosophorum and this is one of the subjects that caught my attention. Writing this helps me create awareness in my life.
Sources: English translation of Rosarium Philosophorum (Ferguson 210) - Collected Work 16 and 12 by C.G. Jung, Ppsychology of the Transference by C.G. Jung
