…　or　possibly　it　was　nervousness；　…　exclaimed：　〃And　your　own　view
  of　the　case？〃　　〃I　believe；〃　Maitland　replied　deliberately；　〃that
  your　father's　death　resulted　from　poison　injected　into　the　blood；
  but　this　is　a　matter　so　easily　settled　that　I　prefer　not　to　theorise
  upon　it。　　There　are　several　poisons　which　might　have　produced　the
  effects　we　have　observed。　　If；　however；　I　am　able　to　prove　this
  conjecture　correct　I　have　still　only　eliminated　one　of　the　three
  hypotheses　and　resolved　the　matter　to　a　choice　between　the　suicide
  and　murder　theories；　yet　that　is　something　gained。　　It　is　because　I
  believe　it　can　be　shown　death　did　not　result　from　natural　causes
  that　I　have　so　strongly　urged　Mr。　Browne　not　to　leave　the　room。〃
  〃Pardon　me；　sir！〃　ejaculated　Browne；　growing　very　dark　and
  threatening。　　〃You　mean　to　insinuate　…　〃　　〃Nothing；〃　continued
  Maitland；　finishing　his　sentence　for　him；　and　then　quietly　ignoring
  the　interruption。　　〃As　I　have　already　said；　I　am　somewhat　familiar
  with　the　usual　methods　of　ferreting　out　crime。　　As　a　lawyer；　and
  also　as　a　chemical　expert；　I　have　listened　to　a　great　deal　of
  evidence　in　criminal　cases；　and　in　this　and　other　ways；　learned
  the　lines　upon　which　detectives　may　confidently　be　expected　to　act；
  when　once　they　have　set　up　an　hypothesis。　　The　means　by　which　they
  arrive　at　their　hypotheses　occasionally　surpass　all　understanding；
  and　we　have；　therefore；　no　assurance　as　to　the　view　they　will　take
  of　this　case。　　The　first　thing　they　will　do　will　be　to　make　what
  they　will　call　a　'thorough　examination'　of　the　premises；　but　a
  study　of　chemistry　gives　to　the　word　'thorough'　a　significance　of
  which　they　have　no　conception。　　It　is　to　shorten　this　examination
  as　much　as　possible；　…　to　prevent　it　from　being　more　tiresome　to
  you　than　is　absolutely　necessary；〃　he　said　to　Gwen；　〃that　I　have
  taken　the　liberty　of　ascertaining　and　recording　most　of　the　data
  the　officers　will　require。〃
  〃Believe　me；〃　Gwen　said　to　him　in　an　undertone　not　intended　for　the
  rest　of　us；　though　we　heard　it；　〃I　am　duly　grateful　for　your
  consideration　and　shall　find　a　fitting　time　to　thank　you。〃
  With　no　other　reply　than　a　deprecating　gesture；　Maitland　continued：
  〃Now　let　us　look　at　the　matter　from　the　standpoint　of　the　officers。
  〃They　must　first　determine　in　their　own　minds　how　Mr。　Darrow　met　his
  death。　　This　will　constitute　the　basis　of　their　first　hypothesis。
  I　say　'first'　because　they　are　liable　to　change　it　at　any　moment　it
  seems　to　them　untenable。　　If　they　conclude　that　death　resulted　from
  natural　causes；　I　shall　doubtless　be　able　to　induce　them　to　waive
  that　view　of　the　case　until　I　have　been　given　time　to　prove　it
  untenable　…　if　I　can　…　and　to　act　for　the　present　upon　one　of　the
  other　two　possible　theories。　　It　appears；　from　our　present
  knowledge　of　the　case；　that；　whichever　one　of　these　they　choose；
  the　same　difficulty　will　confront　them。〃
  Gwen　looked　at　him　inquiringly　and　he　continued；　answering　the
  question　in　her　eyes：
  〃This　is　what　I　mean。　　Your　father；　whether　he　committed　suicide
  or　was　murdered；　in　all　probability　met　his　death　through　that
  almost　imperceptible　wound　under　his　chin。　　This　wound；　so　far　as
  I　have　yet　been　able　to　examine　it　without　a　glass；　was　made　with
  a　somewhat　blunt　instrument；　able；　apparently；　to　little　more　than
  puncture　the　skin　and　draw　a　drop　or　so　of　blood。　　Of　course；　on
  such　a　theory；　death　must　have　resulted　from　poisoning。　　The
  essential　point　is：　Where　is　the　instrument　that　inflicted　the
  wound？〃
  〃Might　it　not　be　buried　in　the　flesh？〃　Gwen　asked。
  〃Possibly；　but　as　I　have　not　been　able　to　find　it　I　cannot　believe
  it　very　likely；　though　closer　search　may　reveal　it；〃　replied
  Maitland。　　〃Your　father's　right　forefinger；〃　he　continued；　〃is
  slightly　stained　with　blood；　but　the　wound　is　of　a　nature　which
  could　not　have　been　caused　by　a　finger　nail　previously　poisoned。
  Since　we　know　he　pressed　his　hand　to　his　throat　this　blood…stain
  makes　no　more　strongly　toward　the　truth　of　the　suicide　theory　than
  it　does　toward　that　of　the　murder　hypothesis。　　Suppose　now；　for　we
  must　look　at　all　sides　of　the　question；　the　officers　begin　to　act
  upon　the　assumption　that　murder　has　been　committed。　　What　will
  they　then　do？　　They　will　satisfy　themselves　that　the　east　window
  was　opened　six　and　three…quarters　inches　and　securely　fastened　in
  that　position；　that　the　two　south　windows　were　closed　and　fastened
  and　that　the　blinds　thereof　were　also　closed。　　They　will　ascertain
  the　time　when　death　occurred；　…　we　can　easily　tell　them；　…　and　this
  will　show　them　that　neither　of　the　blinds　on　the　south　side　could
  have　been　opened　without　so　increasing　the　light　in　the　room　as　to
  be　sure　to　attract　our　attention。　　They　will　learn　also　that　the
  folding　doors　were　locked；　as　they　are　now；　on　this　side　and　that
  these　two　gentlemen　＇indicating　Browne　and　Herne＇　sat　against　them。
  They　will　then　turn　to　the　hall　door　as　the　only　possible　means　of
  entrance　and　I　shall　tell　them　that　the　Doctor　and　I　sat　directly
  in　front　of　this　door　and　between　it　and　Mr。　Darrow。　　I　have　taken
  the　liberty　to　cut　the　carpet　to　mark　the　positions　of　our　chairs。
  In　view　of　all　these　facts　what　must　they　conclude？　　Simply　this：
  no　one　entered　the　room；　did　the　deed；　and　then　left　it；　at　least
  not　without　being　observed。〃　　〃But　surely；〃　I　ventured　to　suggest；
  〃you　do　not　think　they　will　presume　to　question　the　testimony　of
  all　of　us　that　no　one　was　observed。〃
  〃That　is　all　negative　evidence；〃　he　replied；　〃and　does　not
  conclusively　prove　that　another　might　not　have　observed　what　we
  failed　to　detect。　　However；　it　is　all　so　self…evident　that　they
  will　not　question　it。　　I　know　so　well　their　methods　of　reasoning
  that　I　am　already　prepared　to　refute　their　conclusions　at　every
  point；　without；　I　regret　to　say；　being　myself　able　to　solve　the
  mystery；　though　I　may　say　in　passing　that　I　purposely　am　refraining
  from　formulating　any　theory　whatever　until　I　have　ascertained
  everything　which　it　is　possible　to　learn　in　the　matter。　　In　this　way
  I　hope　to　avoid　the　error　into　which　the　detective　is　so　prone　to
  fall。　　Once　you　set　up　an　hypothesis　you　unconsciously；　and　in　spite
  of　yourself；　accentuate　unduly　the　importance　of　all　data　making
  toward　that　hypothesis；　while；　on　the　other　hand　you　either　utterly
  neglect；　misconstrue；　or　fail　to　fully　appreciate；　the　evidence
  oppugnant　to　your　theory。　　In　chemical　research　I　gather　the　material
  for　an　entire　series　of　experiments　before　performing　any；　so　that
  the　first　few　shall　not；　either　by　satisfying　or　discouraging　me；
  cause　me　to　leave　the　bush　half　beaten。
  〃Let　us　see　how；　from　the　officers'　standpoint；　the　murder　hypothesis
  now　stands。　　No　assassin；　it　will　be　clear　to　them；　could　have
  entered　or　left　this　room　unobserved。　　If；　therefore；　a　man　did　enter
  the　room　and　kill　our　friend；　we；　all　of　us；　must　be　his　accomplices。〃
  This　remark　drew　some　sort　of　exclamatory　protest　from　every　other
  person　in　the　room　save　Browne。
  〃Ah；　that　is　probably　the　true　solution；〃　said　the　artist　with
  ill…concealed　disgust。
  This　remark　and　the　tone　in　which　it　was　uttered　would　have　been
  discourteous　under　any　circumstances；　at　this　particular　time　and　in
  the　painful　situation　in　which　we　all　found　ourselves　it　was　boorish
  almost　beyond　endurance。
  There　was　nothing　in　Maitland's　manner　to　indicate　that　he　had　heard
  Browne's　remark；　as　he　quietly　continued：
  〃You　see　this　cold…blooded　view；　the　mere　statement　of　which　causes
  you　all　to　shudder；　…　the　more　so　because　one　of　our　number　is　the
  daughter　of　the　dead　man；　…　is　not　to　be　entertained　a　moment　and
  is　only　mentioned　to　show　the　logical　chain　which　will　force　the
  officers　into　the　certain　conviction　that　no　assassin　did　enter　or
  leave　this　room。　What；　then；　remains　of　their　theory？　　Two
  possibilities。　　First；　the　murderer　may　have　done　the　deed　without
  entering。　　If　so；　it　is　clear　that　he　must　have　made　use　of　the
  partly…opened　window。　　This　seems　so　likely　that　they　will　seize
  upon　it　with　avidity。　　At　first　they　will　suggest　that　the　assassin
  reached　in　at　the　window　and　struck　his　victim　as　he　sat　by　it。
  This；　they　will　urge；　accounts　for　our　not　finding　the　weapon；　and
  they　will　be　so　sure　that　this　is　the　correct　solution　of　the
  problem　that　I　shall　probably　have　to　point　out　to　them　its　patent
  absurdity。　　This　illustrates　the　danger　of　forming　an　hypothesis
  from　imperfect　data。　　Remind　them　that　Mr。　Darrow　did　not　sit　by
  the　window；　but　eight　feet　three　and　one…half　inches　from　it；　in
  almost　the　exact　centre　of　the　room；　and　their　theory　falls　to　the
  ground；　only　to　be　hastily　replaced；　as　a　drowning　man　catches　at　a
  straw；　by　a　slightly　varied　theory。　　If　the　victim　sat　that　distance
  from　the　window；　they　will　inform　us；　it　is　clear　the　murderous
  implement　must　have　been　thrown　or　shot　at　him　by　the　assassin。〃
  〃Indeed；〃　said　Mr。　Herne；　〃though　I　had　not　thought　of　that　theory
  it　seems　to　me　so　plausible；　now　that　you　mention　it；　that　I　think
  the　officers　will　show　rare　acumen　if　they　adopt　it。　　Very　properly
  may　they　hold　that　some　projectile　might　have　been　shot　through　the
  partly　opened　window　and　none　of　us　have　detected　t