traces　and　see　if　they　do　not　point　to　my　conclusion。
  〃After　the　publication　of　the　article　in　the　'Matin'　and　my
  conversation　with　the　examining　magistrate　on　the　journey　from　Paris
  to　Epinaysur…Orge；　I　was　certain　that　The　Yellow　Room　had　been
  hermetically　sealed；　so　to　speak；　and　that　consequently　the　murderer
  had　escaped　before　Mademoiselle　Stangerson　had　gone　into　her　chamber
  at　midnight。
  〃At　the　time　I　was　much　puzzled。　　Mademoiselle　Stangerson　could
  not　have　been　her　own　murderer；　since　the　evidences　pointed　to　some
  other　person。　　The　assassin；　then；　had　come　before。　　If　that　were　so；
  how　was　it　that　Mademoiselle　had　been　attacked　after？　　or　rather；
  that　she　appeared　to　have　been　attacked　after？　　It　was　necessary　for
  me　to　reconstruct　the　occurrence　and　make　of　it　two　phases　…　each
  separated　from　the　other；　in　time；　by　the　space　of　several　hours。
  One　phase　in　which　Mademoiselle　Stangerson　had　really　been　attacked
  …　the　other　phase　in　which　those　who　heard　her　cries　thought　she
  was　being　attacked。　　I　had　not　then　examined　The　Yellow　Room。　　What
  were　the　marks　on　Mademoiselle　Stangerson？　　There　were　marks　of
  strangulation　and　the　wound　from　a　hard　blow　on　the　temple。　　The
  marks　of　strangulation　did　not　interest　me　much；　they　might　have
  been　made　before；　and　Mademoiselle　Stangerson　could　have　concealed
  them　by　a　collarette；　or　any　similar　article　of　apparel。　　I　had　to
  suppose　this　the　moment　I　was　compelled　to　reconstruct　the　occurrence
  by　two　phases。　　Mademoiselle　Stangerson　had；　no　doubt；　her　own
  reasons　for　so　doing；　since　she　had　told　her　father　nothing　of　it；
  and　had　made　it　understood　to　the　examining　magistrate　that　the
  attack　had　taken　place　in　the　night；　during　the　second　phase。　　She
  was　forced　to　say　that；　otherwise　her　father　would　have　questioned
  her　as　to　her　reason　for　having　said　nothing　about　it。
  〃But　I　could　not　explain　the　blow　on　the　temple。　　I　understood　it
  even　less　when　I　learned　that　the　mutton…bone　had　been　found　in　her
  room。　　She　could　not　hide　the　fact　that　she　had　been　struck　on　the
  head；　and　yet　that　wound　appeared　evidently　to　have　been　inflicted
  during　the　first　phase；　since　it　required　the　presence　of　the
  murderer！　　I　thought　Mademoiselle　Stangerson　had　hidden　the　wound
  by　arranging　her　hair　in　bands　on　her　forehead。
  〃As　to　the　mark　of　the　hand　on　the　wall；　that　had　evidently　been
  made　during　the　first　phase　…　when　the　murderer　was　really　there。
  All　the　traces　of　his　presence　had　naturally　been　left　during　the
  first　phase；　the　mutton…bone；　the　black　footprints；　the　Basque　cap；
  the　handkerchief；　the　blood　on　the　wall；　on　the　door；　and　on　the
  floor。　　If　those　traces　were　still　all　there；　they　showed　that
  Mademoiselle　Stangerson　…　who　desired　that　nothing　should　be　known
  …　had　not　yet　had　time　to　clear　them　away。　　This　led　me　to　the
  conclusion　that　the　two　phases　had　taken　place　one　shortly　after
  the　other。　　She　had　not　had　the　opportunity；　after　leaving　her　room
  and　going　back　to　the　laboratory　to　her　father；　to　get　back　again
  to　her　room　and　put　it　in　order。　　Her　father　was　all　the　time　with
  her；　working。　　So　that　after　the　first　phase　she　did　not　re…enter
  her　chamber　till　midnight。　　Daddy　Jacques　was　there　at　ten　o'clock；
  as　he　was　every　night；　but　he　went　in　merely　to　close　the　blinds
  and　light　the　night…light。　　Owing　to　her　disturbed　state　of　mind
  she　had　forgotten　that　Daddy　Jacques　would　go　into　her　room　and
  had　begged　him　not　to　trouble　himself。　　All　this　was　set　forth　in
  the　article　in　the　'Matin。'　Daddy　Jacques　did　go；　however；　and；　in
  the　dim　light　of　the　room；　saw　nothing。
  〃Mademoiselle　Stangerson　must　have　lived　some　anxious　moments　while
  Daddy　Jacques　was　absent；　but　I　think　she　was　not　aware　that　so
  many　evidences　had　been　left。　　After　she　had　been　attacked　she　had
  only　time　to　hide　the　traces　of　the　man's　fingers　on　her　neck　and
  to　hurry　to　the　laboratory。　　Had　she　known　of　the　bone；　the　cap；
  and　the　handkerchief；　she　would　have　made　away　with　them　after　she
  had　gone　back　to　her　chamber　at　midnight。　　She　did　not　see　them；　and
  undressed　by　the　uncertain　glimmer　of　the　night　light。　　She　went　to
  bed；　worn…out　by　anxiety　and　fear　…　a　fear　that　had　made　her　remain
  in　the　laboratory　as　late　as　possible。
  〃My　reasoning　had　thus　brought　me　to　the　second　phase　of　the　tragedy；
  when　Mademoiselle　Stangerson　was　alone　in　the　room。　　I　had　now　to
  explain　the　revolver　shots　fired　during　the　second　phase。　　Cries　of
  'Help！　…　Murder！'　had　been　heard。　　How　to　explain　these？　　As　to　the
  cries；　I　was　in　no　difficulty；　since　she　was　alone　in　her　room　these
  could　result　from　nightmare　only。　　My　explanation　of　the　struggle　and
  noise　that　were　heard　is　simply　that　in　her　nightmare　she　was　haunted
  by　the　terrible　experience　she　had　passed　through　in　the　afternoon。
  In　her　dream　she　sees　the　murderer　about　to　spring　upon　her　and　she
  cries；　'Help！　　Murder！'　　Her　hand　wildly　seeks　the　revolver　she　had
  placed　within　her　reach　on　the　night…table　by　the　side　of　her　bed；
  but　her　hand；　striking　the　table；　overturns　it；　and　the　revolver；
  falling　to　the　floor；　discharges　itself；　the　bullet　lodging　in　the
  ceiling。　　I　knew　from　the　first　that　the　bullet　in　the　ceiling　must
  have　resulted　from　an　accident。　　Its　very　position　suggested　an
  accident　to　my　mind；　and　so　fell　in　with　my　theory　of　a　nightmare。
  I　no　longer　doubted　that　the　attack　had　taken　place　before
  Mademoiselle　had　retired　for　the　night。　　After　wakening　from　her
  rightful　dream　and　crying　aloud　for　help；　she　had　fainted。
  〃My　theory；　based　on　the　evidence　of　the　shots　that　were　heard　at
  midnight；　demanded　two　shots　…　one　which　wounded　the　murderer　at
  the　time　of　his　attack；　and　one　fired　at　the　time　of　the　nightmare。
  The　evidence　given　by　the　Berniers　before　the　examining　magistrate
  was　to　the　effect　that　only　one　shot　had　been　heard。　　Monsieur
  Stangerson　testified　to　hearing　a　dull　sound　first　followed　by　a
  sharp　ringing　sound。　　The　dull　sound　I　explained　by　the　falling　of
  the　marble…topped　table；　the　ringing　sound　was　the　shot　from　the
  revolver。　　I　was　now　convinced　I　was　right。　　The　shot　that　had
  wounded　the　hand　of　the　murderer　and　had　caused　it　to　bleed　so　that
  he　left　the　bloody　imprint　on　the　wall　was　fired　by　Mademoiselle　in
  self…defence；　before　the　second　phase；　when　she　had　been　really
  attacked。　　The　shot　in　the　ceiling　which　the　Berniers　heard　was　the
  accidental　shot　during　the　nightmare。
  〃I　had　now　to　explain　the　wound　on　the　temple。　　It　was　not　severe
  enough　to　have　been　made　by　means　of　the　mutton…bone；　and
  Mademoiselle　had　not　attempted　to　hide　it。　　It　must　have　been　made
  during　the　second　phase。　　It　was　to　find　this　out　that　I　went　to
  The　Yellow　Room；　and　I　obtained　my　answer　there。〃
  Rouletabille　drew　a　piece　of　white　folded　paper　from　his　pocket；　and
  drew　out　of　it　an　almost　invisible　object　which　he　held　between　his
  thumb　and　forefinger。
  〃This；　Monsieur　President；〃　he　said；　〃is　a　hair　…　a　blond　hair
  stained　with　blood；　…　it　is　a　hair　from　the　head　of　Mademoiselle
  Stangerson。　　I　found　it　sticking　to　one　of　the　corners　of　the
  overturned　table。　　The　corner　of　the　table　was　itself　stained　with
  blood　…　a　tiny　stain　…　hardly　visible；　but　it　told　me　that；　on
  rising　from　her　bed；　Mademoiselle　Stangerson　had　fallen　heavily
  and　had　struck　her　head　on　the　corner　of　its　marble　top。
  〃I　still　had　to　learn；　in　addition　to　the　name　of　the　assassin；
  which　I　did　later；　the　time　of　the　original　attack。　　I　learned
  this　from　the　examination　of　Mademoiselle　Stangerson　and　her
  father；　though　the　answers　given　by　the　former　were　well　calculated
  to　deceive　the　examining　magistrate　…　Mademoiselle　Stangerson　had
  stated　very　minutely　how　she　had　spent　the　whole　of　her　time　that
  day。　　We　established　the　fact　that　the　murderer　had　introduced
  himself　into　the　pavilion　between　five　and　six　o'clock。　　At　a
  quarter　past　six　the　professor　and　his　daughter　had　resumed　their
  work。　　At　five　the　professor　had　been　with　his　daughter；　and　since
  the　attack　took　place　in　the　professor's　absence　from　his　daughter；
  I　had　to　find　out　just　when　he　left　her。　　The　professor　had　stated
  that　at　the　time　when　he　and　his　daughter　were　about　to　re…enter
  the　laboratory　he　was　met　by　the　keeper　and　held　in　conversation
  about　the　cutting　of　some　wood　and　the　poachers。　　Mademoiselle
  Stangerson　was　not　with　him　then　since　the　professor　said：　'I　left
  the　keeper　and　rejoined　my　daughter　who　was　at　work　in　the
  laboratory。'
  〃It　was　during　that　short　interval　of　time　that　the　tragedy　took
  place。　　That　is　certain。　　In　my　mind's　eye　I　saw　Mademoiselle
  Stangerson　re…enter　the　pavilion；　go　to　her　room　to　take　off　her
  hat；　and　find　herself　faced　by　the　murderer。　　He　had　been　in　the
  pavilion　for　some　time　waiting　for　her。　　He　had　arranged　to　pass
  the　whole　night　there。　　He　had　taken　off　Daddy　Jacques's　boots；　he
  had　removed　the　papers　from　the　cabinet；　and　had　then　slipped　under
  the　bed。　　Finding　the　time　long；　he　had　risen；　gone　again　into　the
  laboratory；　then　into　the　vestibule；　looked　into　the　garden；　and
  had　seen；　coming　towards　the　pavilion；　Mademoiselle　Stangerson
  …　alone。　　He　would　never　have　dared　to　attack　her　at　that　hour；　if
  he　had　not　found　her　alone