# A hatter's occupational danger beneath the joke

Commentary on Orthodoxy by G. K. Chesterton.

On [CH02.P006](https://glosses.org/orthodoxy/pg16769-r1/CH02.P006/#char=1138,1194): "a hatter is mad because he has to measure the human head"

The joke turns literal measurement into an emblem of the chapter's dangerous mental self-measurement. There is also a material occupational background: a [NIOSH historical backgrounder, published 4 March 2010](https://archive.cdc.gov/www_cdc_gov/niosh/updates/upd-03-04-10.html), describes neurological and behavioral symptoms among hat makers chronically exposed to mercury in poorly ventilated workshops. The agency associates that history with the expression ‘mad as a hatter’. This supplies a useful counterpoint to the deliberately ‘flippant’ explanation: head measurement is a pun, whereas work with mercury was a real hazard. The occupational evidence does not establish the exact origin of the idiom, and Chesterton neither offers a medical explanation here nor explicitly identifies Carroll's Hatter as his reference.

## Sources

- [NIOSH Backgrounder: Alice's Mad Hatter & Work-Related Illness (2010)](https://archive.cdc.gov/www_cdc_gov/niosh/updates/upd-03-04-10.html), Dated 4 March 2010; opening substantive paragraph beginning ‘The Hatter’s erratic, agitated behavior’

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