Date: 1664

"The parts of the blood which penetrate as far as the brain serve not only to nourish and sustain its substance, but also and primarily to produce in it a certain very fine wind, or rather a very lively and pure flame, which is called the animal spirits."

— Descartes, René (1596-1650)

Date: 1694

"As Fire under Ashes, nor the Sun obscured from our sight by thick Clouds, afford not their full lustre, so the Soul overwhelmed in moist or faulty matter, is darkned, and Reason thereby overclouded"

— Aristotle [pseud.]

Date: Monday, July 13, 1724

"Oh, Jealousy!--All other Storms are Calms / To Thee!--Thou Conflagration of the Soul!"

— Hill, Aaron (1685-1750)

Date: 1755

"THE SHOCK OF RECEIVING MY OWN LETTER did not excite a sudden Gust of unwarrantable Passion, but prey'd upon my Heart with the slow and eating Fire of Distraction and Despair, 'till it ended in a Fever, which now remains upon my Spirits; and which, I fear, I shall find a difficult Task to overcome."

— Charke [née Cibber; other married name Sacheverell], Charlotte [alias Mr Brown] (1713-1760)