After anesthesia was introduced in the U.S. in 1844, the phrase came flguratively to mean to `deal with a bad situation resolutely,' as in Rudyard Kipling's lines  Bite the bullet, old man,/ And don't let them think you're afraid. 
( ( ( After ( anesthesia ( was ( ( introduced ( in ( the U.S. ) ) ) ( in 1844 ) ) ) ) ) ( , ( ( the phrase ) ( ( came flguratively ) ( to ( mean ( to ( ` ( ( deal ( with ( a ( bad ( situation resolutely ) ) ) ) ) ( , ( ' ( ( ( ( ( as ( in ( ( Rudyard ( Kipling 's ) ) ( lines Bite ) ) ) ) ( the bullet ) ) , ) ( old man ) ) , ) ) ) ) ) ) ) ) ) ) ) ) ( / ( ( And ( ( do n't ) ( let ( them ( think ( you ( 're afraid ) ) ) ) ) ) ) . ) ) )
(ROOT (FRAG (S (SBAR (IN After) (S (NP (NN anesthesia)) (VP (VBD was) (VP (VBN introduced) (PP (IN in) (NP (DT the) (NNP U.S.))) (PP (IN in) (NP (CD 1844))))))) (, ,) (NP (DT the) (NN phrase)) (VP (VBD came) (ADVP (RB flguratively)) (S (VP (TO to) (VP (VB mean) (PP (TO to) (NP (`` `) (VP (NP (NN deal)) (PP (IN with) (NP (DT a) (JJ bad) (NN situation) (NN resolutely)))) (, ,) ('' ') (NP (NP (ADVP (RB as) (PP (IN in) (NP (NP (NNP Rudyard) (NNP Kipling) (POS 's)) (NNS lines) (NN Bite)))) (DT the) (NN bullet)) (, ,) (NP (JJ old) (NN man)) (, ,))))))))) (: /) (FRAG (CC And) (S (VP (VBP do) (RB n't) (VP (VB let) (SBAR (S (NP (PRP them)) (VP (VBP think) (SBAR (S (NP (PRP you)) (VP (VBP 're) (ADJP (JJ afraid)))))))))))) (. .)))
Anesthesia was first used in the United States in 1844.
( Anesthesia ( ( ( was first ) ( ( used ( in ( the ( United States ) ) ) ) ( in 1844 ) ) ) . ) )
(ROOT (S (NP (NNP Anesthesia)) (VP (VBD was) (ADVP (RB first)) (VP (VBN used) (PP (IN in) (NP (DT the) (NNP United) (NNPS States))) (PP (IN in) (NP (CD 1844))))) (. .)))