closely　to　their　heads；　when　feeling　savage；　from　their　progenitors　having　voluntarily　acted　in　this　manner　in　order　to　protect　their　ears　from　being　torn　by　their　antagonists；　for　those　animals　which　do　not　fight　with　their　teeth　do　not　thus　express　a　savage　state　of　mind。　We　may　infer　as　highly　probable　that　we　ourselves　have　acquired　the　habit　of　contracting　the　muscles　round　the　eyes；　whilst　crying　gently；　that　is；　without　the　utterance　of　any　loud　sound；　from　our　progenitors；　especially　during　infancy；　having　experienced；　during　the　act　of　screaming；　an　uncomfortable　sensation　in　their　eyeballs。　　Again；　some　highly　expressive　movements　result　from　the　endeavour　to　cheek　or　prevent　other　expressive　movements；　thus　the　obliquity　of　the　eyebrows　and　the　drawing　down　of　the　corners　of　the　mouth　follow　from　the　endeavour　to　prevent　a　screaming…fit　from　coming　on；　or　to　cheek　it　after　it　has　come　on。　Here　it　is　obvious　that　the　consciousness　and　will　must　at　first　have　come　into　play；　not　that　we　are　conscious　in　these　or　in　other　such　cases　what　muscles　are　brought　into　action；　any　more　than　when　we　perform　the　most　ordinary　voluntary　movements。
  With　respect　to　the　expressive　movements　due　to　the　principle　of　antithesis；　it　is　clear　that　the　will　has　intervened；　though　in　a　remote　and　indirect　manner。　　So　again　with　the　movements　coming　under　our　third　principle；　these；　in　as　far　as　they　are　influenced　by　nerve…force　readily　passing　along　habitual　channels；　have　been　determined　by　former　and　repeated　exertions　of　the　will。　The　effects　indirectly　due　to　this　latter　agency　are　often　combined　in　a　complex　manner；　through　the　force　of　habit　and　association；　with　those　directly　resulting　from　the　excitement　of　the　cerebro…spinal　system。　This　seems　to　be　the　case　with　the　increased　action　of　the　heart　under　the　influence　of　any　strong　emotion。　　When　an　animal　erects　its　hair；　assumes　a　threatening　attitude；　and　utters　fierce　sounds；　in　order　to　terrify　an　enemy；　we　see　a　curious　combination　of　movements　which　were　originally　voluntary　with　those　that　are　involuntary。　It　is；　however；　possible　that　even　strictly　involuntary　actions；　such　as　the　erection　of　the　hair；　may　have　been　affected　by　the　mysterious　power　of　the　will。
  Some　expressive　movements　may　have　arisen　spontaneously；　in　association　with　certain　states　of　the　mind；　like　the　tricks　lately　referred　to；　and　afterwards　been　inherited。　But　I　know　of　no　evidence　rendering　this　view　probable。
  The　power　of　communication　between　the　members　of　the　same　tribe　by　means　of　language　has　been　of　paramount　importance　in　the　development　of　man；　and　the　force　of　language　is　much　aided　by　the　expressive　movements　of　the　face　and　body。　We　perceive　this　at　once　when　we　converse　on　an　important　subject　with　any　person　whose　face　is　concealed。　　Nevertheless　there　are　no　grounds；　as　far　as　I　can　discover；　for　believing　that　any　muscle　has　been　developed　or　even　modified　exclusively　for　the　sake　of　expression。　　The　vocal　and　other　sound…producing　organs；　by　which　various　expressive　noises　are　produced；　seem　to　form　a　partial　exception；　but　I　have　elsewhere　attempted　to　show　that　these　organs　were　first　developed　for　sexual　purposes；　in　order　that　one　sex　might　call　or　charm　the　other。　Nor　can　I　discover　grounds　for　believing　that　any　inherited　movement；　which　now　serves　as　a　means　of　expression；　was　at　first　voluntarily　and　consciously　performed　for　this　special　purpose；like　some　of　the　gestures　and　the　finger…language　used　by　the　deaf　and　dumb。　On　the　contrary；　every　true　or　inherited　movement　of　expression　seems　to　have　had　some　natural　and　independent　origin。　But　when　once　acquired；　such　movements　may　be　voluntarily　and　consciously　employed　as　a　means　of　communication。　Even　infants；　if　carefully　attended　to；　find　out　at　a　very　early　age　that　their　screaming　brings　relief；　and　they　soon　voluntarily　practise　it。　　We　may　frequently　see　a　person　voluntarily　raising　his　eyebrows　to　express　surprise；　or　smiling　to　express　pretended　satisfaction　and　acquiescence。　　A　man　often　wishes　to　make　certain　gestures　conspicuous　or　demonstrative；　and　will　raise　his　extended　arms　with　widely　opened　fingers　above　his　head；　to　show　astonishment；　or　lift　his　shoulders　to　his　ears；　to　show　that　he　cannot　or　will　not　do　something。　The　tendency　to　such　movements　will　be　strengthened　or　increased　by　their　being　thus　voluntarily　and　repeatedly　performed；　and　the　effects　may　be　inherited。
  It　is　perhaps　worth　consideration　whether　movements　at　first　used　only　by　one　or　a　few　individuals　to　express　a　certain　state　of　mind　may　not　sometimes　have　spread　to　others；　and　ultimately　have　become　universal；　through　the　power　of　conscious　and　unconscious　imitation。　　That　there　exists　in　man　a　strong　tendency　to　imitation；　independently　of　the　conscious　will；　is　certain。　This　is　exhibited　in　the　most　extraordinary　manner　in　certain　brain　diseases；　especially　at　the　commencement　of　inflammatory　softening　of　the　brain；　and　has　been　called　the　〃echo　sign。〃　Patients　thus　affected　imitate；　without　understanding　every　absurd　gesture　which　is　made；　and　every　word　which　is　uttered　near　them；　even　in　a　foreign　language。＇1＇　In　the　case　of　animals；　the　jackal　and　wolf　have　learnt　under　confinement　to　imitate　the　barking　of　the　dog。　　How　the　barking　of　the　dog；　which　serves　to　express　various　emotions　and　desires；　and　which　is　so　remarkable　from　having　been　acquired　since　the　animal　was　domesticated；　and　from　being　inherited　in　different　degrees　by　different　breeds；　was　first　learnt　we　do　not　know；　but　may　we　not　suspect　that　imitation　has　had　something　to　do　with　its　acquisition；　owing　to　dogs　having　long　lived　in　strict　association　with　so　loquacious　an　animal　as　man？
  ＇1＇　See　the　interesting　facts　given　by　Dr。　Bateman　on　‘Aphasia；'　1870；　p。　　110。
  In　the　course　of　the　foregoing　remarks　and　throughout　this　volume；　I　have　often　felt　much　difficulty　about　the　proper　application　of　the　terms；　will；　consciousness；　and　intention。　　Actions；　which　were　at　first　voluntary；　soon　became　habitual；　and　at　last　hereditary；　and　may　then　be　performed　even　in　opposition　to　the　will。　Although　they　often　reveal　the　state　of　the　mind；　this　result　was　not　at　first　either　intended　or　expected。　　Even　such　words　as　that　〃certain　movements　serve　as　a　means　of　expression〃　are　apt　to　mislead；　as　they　imply　that　this　was　their　primary　purpose　or　object。　This；　however；　seems　rarely　or　never　to　have　been　the　case；　the　movements　having　been　at　first　either　of　some　direct　use；　or　the　indirect　effect　of　the　excited　state　of　the　sensorium。　An　infant　may　scream　either　intentionally　or　instinctively　to　show　that　it　wants　food；　but　it　has　no　wish　or　intention　to　draw　its　features　into　the　peculiar　form　which　so　plainly　indicates　misery；　yet　some　of　the　most　characteristic　expressions　exhibited　by　man　are　derived　from　the　act　of　screaming；　as　has　been　explained。
  Although　most　of　our　expressive　actions　are　innate　or　instinctive；　as　is　admitted　by　everyone；　it　is　a　different　question　whether　we　have　any　instinctive　power　of　recognizing　them。　　This　has　generally　been　assumed　to　be　the　case；　but　the　assumption　has　been　strongly　controverted　by　M。　Lemoine。＇2＇　Monkeys　soon　learn　to　distinguish；　not　only　the　tones　of　voice　of　their　masters；　but　the　expression　of　their　faces；　as　is　asserted　by　a　careful　observer。＇3＇　Dogs　well　know　the　difference　between　caressing　and　threatening　gestures　or　tones；　and　they　seem　to　recognize　a　compassionate　tone。　　But　as　far　as　I　can　make　out；　after　repeated　trials；　they　do　not　understand　any　movement　confined　to　the　features；　excepting　a　smile　or　laugh；　and　this　they　appear；　at　least　in　some　cases；　to　recognize。　This　limited　amount　of　knowledge　has　probably　been　gained；　both　by　monkeys　and　dogs；　through　their　associating　harsh　or　kind　treatment　with　our　actions；　and　the　knowledge　certainly　is　not　instinctive。　Children；　no　doubt；　would　soon　learn　the　movements　of　expression　in　their　elders　in　the　same　manner　as　animals　learn　those　of　man。　Moreover；　when　a　child　cries　or　laughs；　he　knows　in　a　general　manner　what　he　is　doing　and　what　he　feels；　so　that　a　very　small　exertion　of　reason　would　tell　him　what　crying　or　laughing　meant　in　others。　But　the　question　is；　do　our　children　acquire　their　knowledge　of　expression　solely　by　experience　through　the　power　of　association　and　reason？
  As　most　of　the　movements　of　expression　must　have　been　gradually　acquired；　afterwards　becoming　instinctive；　there　seems　to　be　some　degree　of　_a　priori_　probability　that　their　recognition　would　likewise　have　become　instinctive。　There　is；　at　least；　no　greater　difficulty　in　believing　this　than　in　admitting　that；　when　a　female　quadruped　first　bears　young；　she　knows　the　cry　of　distress　of　her　offspring；　or　than　in　admitting　that　many　animals　instinctively　recognize　and　fear　their　enemies；　and　of　both　these　statements　there　can　be　no　reasonable　doubt。　It　is　however　extremely　difficult　to　prove　that　our　children　instinctively　recognize　any　expression。　　I　attended　to　this　point　in　my　first…born　infant；　who　could　not　have　learnt　anything　by　associating　with　other　children；　and　I　was　convinced　that　he　understood　a　smile　and　received　pleasure　from　seeing　one；　answering　it　by　anothe