# Quicksilver

**Argentum vivum*, *hydrargyrum*; mercury*

**Known today as.** Elemental mercury, and its salts such as calomel and corrosive sublimate.

Kind: Mineral  
Qualities: Cold and moist (Galenic tradition).  
Poisoning: Mercury, arsenic, lead, and antimony (https://thethinkingpress.org/materia-medica/poisons/heavy-metal)  
Toxic: yes

> **Caution.** Poisonous, especially as vapor.

## What does modern science say?

A cumulative poison of the nerves and kidneys; its vapor is the most dangerous form.

## Pharmacognosy and toxicology

- **mercury**: the metal

**Mechanism.** The metal is barely absorbed from the gut; its vapour is, and in the brain it binds the sulphur of proteins.

**Dose.** Swallowed metal usually passes; the vapour of a heated gram is dangerous.

**Standing.** Phased out of thermometers and phased down in dentistry under the Minamata Convention (2013).

## What lore surrounds it?

The shape-changing metal of Hermes, patron of the art; see [Alchemy](https://thethinkingpress.org/inspirations/alchemy).

Mercury left its mark on ordinary speech. Eighteenth- and nineteenth-century hatters cured felt with mercury compounds, and long exposure gave many of them tremors, slurred speech, and hallucinations, so common among the hatmakers of Danbury, Connecticut, that it was called the “Danbury shakes,” and the likeliest source of the phrase “mad as a hatter.”

## What did the older authorities say?

**The alchemists.** Mercury was the principle of fluidity, and with sulfur the parent of all metals; for Paracelsus, one of the three principles with sulfur and salt.

**Paracelsus.** Championed mercury against the new French disease, syphilis, which it was used to treat until the twentieth century: “a night with Venus, a lifetime with Mercury.”

## Sources

- Paracelsus, writings on the French disease.
- Pliny, *Natural History* XXXIII.
- Wikipedia, “Mad as a hatter.”
- Clarkson, T. W., and Magos, L. (2006). “The toxicology of mercury and its chemical compounds.” *Critical Reviews in Toxicology* 36.

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*Quicksilver.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-09-25. The Thinking Press. https://thethinkingpress.org/materia-medica/quicksilver

Historical description, not medical advice.