Leucine,

Chambers's Encyclopaedia, Volume 6: Humber to Malta, p. 595

Leucine, or AMIDO-CAPROIC ACID, a product of the decomposition of albuminous materials occurring in many of the juices of the animal body: formula C_6H_{11}O_2NH_2. A substance isomeric, but not identical, with natural leucine can be prepared artificially.

Source scan(s): p. 0610