In Alchemy, an Athanor is a furnace used to create physical, mystical, and moral transformations. The image above shows a man sliding another figure into what looks like an old-fashioned #oven - but instead of smoke, images of the man's thoughts billow out of the oven's top. The " baker " is in fact an apothecary, the "oven" is a distillation apparatus, and the man whose thoughts are boiling out of his head is someone being treated (metaphorically) for madness.

caption below:
Aprochez vous qu'avez la teste pleine
de phantasie, qui vous met en grande peine
assurez vous de ce Maistre sçavant,
quil voz humeurs seicherat tellemant,
dedans ce four, qu'aurez en peu de temps,
grand allegeance de beaucoup de torments,
aussi serez purge per ses brevages
qu'incontinant deviendrez du tout sages.

source: https://resobscura.blogspot.com/2015/12/