The Twelve Operations · Operation 5 · Nigredo
Putrefactio Putrefaction
In the vessel. The joined matter is left to rot in a sealed vessel until it turns black. The raven and the tomb are its emblems.
In a life. The necessary decay between one form and the next. Even the improved old form has to die. It is lived as stuckness, the long wait between an ending and a beginning in which nothing seems to happen.
What is decomposing in your life that you keep trying to put back together?
The full section on putrefaction, with the other eleven operations and the four stages, is in The Magnum Opus.