Is it farther or further?
late 14c. (n.), "action of urging, prompting, inciting," noun of action from excite (v.). As a present participle adjective, from 1811 in sense "causing disease." Sense of "causing excitement" is from 1826.
mid-14c., "to move, stir up, instigate," from Old French esciter (12c.) or directly from Latin excitare "rouse, call out, summon forth, produce," frequentative of exciere "call forth, instigate," from ex- "out" (see ex-) + ciere "set in motion, call" (see cite). Of feelings, from late 14c. Of bodily organs or tissues, from 1831. Main modern sense of "emotionally agitate" is first attested 1821.