All you connoisseurs who lament that new versions of old classics—the Corvette, Astroturf, metal bats—just do not measure up to the original can cross one example off your list: absinthe.

The bitter green liqueur made from wormwood was for decades the toast of Europe, imbibed by the likes of van Gogh, Degas, Toulouse-Lautrec and Picasso to, it was believed, spur their creativity. For absinthe was deemed more drug than drink: thujone, a natural essence found in common wormwood (Artemisia absinthium L.) and Roman wormwood (Artemisia pontica L.) that was widely believed to be its active ingredient, induces convulsions like those suffered by people with epilepsy, and was thought to account for absinthe’s supposedly mind-altering properties. Thujone was thought to explain absinthe’s reputation as a “green fairy” and a “green muse.” (The original absinthe also contained green anise, Pimpinella anisum L.; hyssop, Hyssopus officinalis L.; lemon balm, Melissa officinalis L. and Florence fennel, Foeniculum vulgare Mill.)

I couldn’t avoid all those “supposedly”s and “thought to”s in the paragraph above: it turns out that there had been only a single actual test of how much thujone classic absinthe contained.