Back in the days (1893) when few compounds were known, new ones could end up being named after the discoverer. Thus Feist is known for the compound bearing his name; the 2,3 carboxylic acid of methylenecyclopropane (<strong>1</strong>, with Me replaced by CO<sub>2</sub>H). Compound <strong>1</strong> itself nowadays is used to calibrate chiroptical calculations[1], which is what brought it to my attention.