Walnut — brain signature
shell and convoluted kernel
The walnut's convoluted kernel was widely used as a visual example of a brain-like signature in later signature lore. The head coordinate is a target-organ projection of that classification, not a claim that walnut form diagnoses or treats the brain; the medicinal inference is historically important but scientifically superseded.
Point 1 of 6 in Doctrine of Signatures
Cross-tradition overlaps
No overlapping points are registered for this point.
Sources
Paracelsus, Paragranum (primary)
Paragranum discusses the signatura as a way of reading the hidden virtue of natural things; see Book IV, the discussion of signatures and external signs.
Roy Porter, The Greatest Benefit to Mankind: A Medical History of Humanity (scholarly_modern)
Historical account of early-modern European medicine and Paracelsian natural philosophy; see the chapters on Renaissance medicine and Paracelsianism.