You will learn later that the person who usually poured out Mrs. Inglethorp's medicine was always extremely careful not to shake the bottle, but to leave the sediment at the bottom of it undisturbed. 
( You ( ( will ( ( learn later ) ( that ( ( ( the person ) ( who ( usually ( ( poured out ) ( ( Mrs. ( Inglethorp 's ) ) medicine ) ) ) ) ) ( ( was always ) ( extremely ( careful ( ( ( ( not ( to ( shake ( the bottle ) ) ) ) , ) but ) ( to ( leave ( ( ( the sediment ) ( at ( ( the bottom ) ( of it ) ) ) ) undisturbed ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP You)) (VP (MD will) (VP (VB learn) (ADVP (RB later)) (SBAR (IN that) (S (NP (NP (DT the) (NN person)) (SBAR (WHNP (WP who)) (S (ADVP (RB usually)) (VP (VBD poured) (PRT (RP out)) (NP (NP (NNP Mrs.) (NNP Inglethorp) (POS 's)) (NN medicine)))))) (VP (VBD was) (ADVP (RB always)) (ADJP (RB extremely) (JJ careful) (S (VP (VP (RB not) (TO to) (VP (VB shake) (NP (DT the) (NN bottle)))) (, ,) (CC but) (VP (TO to) (VP (VB leave) (S (NP (NP (DT the) (NN sediment)) (PP (IN at) (NP (NP (DT the) (NN bottom)) (PP (IN of) (NP (PRP it)))))) (ADJP (JJ undisturbed))))))))))))) (. .)))
The person pouring Mrs. Inglethorp's medicine was always very careful to shake the bottle. 
( ( ( The person ) ( pouring ( ( Mrs. ( Inglethorp 's ) ) medicine ) ) ) ( ( ( was always ) ( very ( careful ( to ( shake ( the bottle ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN person)) (VP (VBG pouring) (NP (NP (NNP Mrs.) (NNP Inglethorp) (POS 's)) (NN medicine)))) (VP (VBD was) (ADVP (RB always)) (ADJP (RB very) (JJ careful) (S (VP (TO to) (VP (VB shake) (NP (DT the) (NN bottle))))))) (. .)))