From Magic to Microscope

From Magic to Microscope

The Doctrine of



Early Modern

Science and

With the support of


A walnut looks like a brain, and therefore could perhaps cure brain diseases — today, a traditional medicinal idea called ‘the doctrine of signatures’ is widely cited in contemporary pharmacy and herbalism. It holds that many minerals, plants and animals have ‘signatures’, i.e. visible resemblance to human organs, bodily fluids or disease symptoms, and that these signatures indicate the curative effects of natural things.

Throughout the centuries, the doctrine of signatures has been veiled by layers of constructions: some argue that it originated from sixteenth-century Swiss physician Paracelsus, some trace it back to antiquity, and some see it as a worldwide universal practice of primitive analogical thinking. Unsurprisingly, the theory of signatures is often taken as an emblem of the superstitious, magical premodern era, in opposition to any scientific worldviews.

This exhibition will offer a historical overview of the theories and practices of signatures in early modern European medicine. We invite you to explore: what is the doctrine of signatures? How did early modern people heal with signatures? And how did the doctrine of signatures shape early modern science?

*Warning: this exhibition contains images of human anatomical models.

Diagram showing the correspondence between human body, medicinal plants with signatures, and constellations. Athanasius Kircher, Ars Magna Lucis Et Umbrae (Amsterdam, 1671). First edition 1646. Image from Smithsonian Libraries, Public Domain.

Exhibition Sections

The Divine Signatures

Signatures And Anatomy​

Elements behind the Signatures

Curing with Signatures

Signatures and Microscope

Explore the Signatures of Things

Click into the circles to see the signature of every plant

Explore the Signatures of Things

Click into the circles to see the signature of every plant