E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Midsummer-Moon Madness.
’Tis Midsummer-moon with you. You are stark mad. Madness is supposed to be affected by the moon, and to be aggravated by summer heat; so it naturally follows that the full moon at midsummer is the time when madness is most outrageous.
