the expression of emotion in man and animals-第15章

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ps　by　which　the　flow　of　nerve…force　through　the　requisite　channels　has　become　habitual　under　certain　emotions。


A　brief　consideration　of　the　outward　signs　of　some　of　the　stronger　sensations　and　emotions　will　best　serve　to　show　us；　although　vaguely；　in　how　complex　a　manner　the　principle　under　consideration　of　the　direct　action　of　the　excited　nervous　system　of　the　body；　is　combined　with　the　principle　of　habitually　associated；　serviceable　movements。

When　animals　suffer　from　an　agony　of　pain；　they　generally　writhe　about　with　frightful　contortions；　and　those　which　habitually　use　their　voices　utter　piercing　cries　or　groans。　Almost　every　muscle　of　the　body　is　brought　into　strong　action。　With　man　the　mouth　may　be　closely　compressed；　or　more　commonly　the　lips　are　retracted；　with　the　teeth　clenched　or　ground　together。　There　is　said　to　be　〃gnashing　of　teeth〃　in　hell；　and　I　have　plainly　heard　the　grinding　of　the　molar　teeth　of　a　cow　which　was　suffering　acutely　from　inflammation　of　the　bowels。　The　female　hippopotamus　in　the　Zoological　Gardens；　when　she　produced　her　young；　suffered　greatly；　she　incessantly　walked　about；　or　rolled　on　her　sides；　opening　and　closing　her　jaws；　and　clattering　her　teeth　together。＇4＇　With　man　the　eyes　stare　wildly　as　in　horrified　astonishment；　or　the　brows　are　heavily　contracted。　Perspiration　bathes　the　body；　and　drops　trickle　down　the　face。　The　circulation　and　respiration　are　much　affected。　Hence　the　nostrils　are　generally　dilated　and　often　quiver；　or　the　breath　may　be　held　until　the　blood　stagnates　in　the　purple　face。　If　the　agony　be　severe　and　prolonged；　these　signs　all　change；　utter　prostration　follows；　with　fainting　or　convulsions。

A　sensitive　nerve　when　irritated　transmits　some　influence　to　the　nerve…cell；　whence　it　proceeds；　and　this　transmits　its　influence；　first　to　the　corresponding　nerve…cell　on　the　opposite　side　of　the　body；　and　then　upwards　and　downwards　along　the　cerebro…spinal　column　to　other　nerve…cells；　to　a　greater　or　less　extent；　according　to　the　strength　of　the　excitement；　so　that；　ultimately；　the　whole　nervous　system　maybe　affected。＇5＇　This　involuntary　transmission　of　nerve…force　may　or　may　not　be　accompanied　by　consciousness。　Why　the　irritation　of　a　nerve…cell　should　generate　or　liberate　nerve…force　is　not　known；　but　that　this　is　the　case　seems　to　be　the　conclusion　arrived　at　by　all　the　greatest　physiologists；　such　as　Muller；　Virchow；　Bernard；　&c。＇6＇　As　Mr。　Herbert　Spencer　remarks；　it　may　be　received　as　an　〃unquestionable　truth　that；　at　any　moment；　the　existing　quantity　of　liberated　nerve…force；　which　in　an　inscrutable　way　produces　in　us　the　state　we　call　feeling；　MUST　expend　itself　in　some　directionMUST　generate　an　equivalent　manifestation　of　force　somewhere；〃　so　that；　when　the　cerebro…spinal　system　is　highly　excited　and　nerve…force　is　liberated　in　excess；　it　may　be　expended　in　intense　sensations；　active　thought；　violent　movements；　or　increased　activity　of　the　glands。＇7＇　Mr。　Spencer　further　maintains　that　an　〃overflow　of　nerve…force；　undirected　by　any　motive；　will　manifestly　take　the　most　habitual　routes；　and；　if　these　do　not　suffice；　will　next　overflow　into　the　less　habitual　ones。〃　Consequently　the　facial　and　respiratory　muscles；　which　are　the　most　used；　will　be　apt　to　be　first　brought　into　action；　then　those　of　the　upper　extremities；　next　those　of　the　lower；　and　finally　those　of　the　whole　body。＇8＇


＇4＇　Mr。　Bartlett；　〃Notes　on　the　Birth　of　a　Hippopotamus；〃　Proc。　　Zoolog。　　Soc。　　1871；　p。　　255。

＇5＇　See；　on　this　subject；　Claude　Bernard；　‘Tissus　Vivants；'　1866；　pp。　316；　337；　358。　　Virchow　expresses　himself　to　almost　exactly　the　same　effect　in　his　essay　〃Ueber　das　Ruckenmark〃　（Sammlung　wissenschaft。　Vortrage；　1871；　s。　　28）。

An　emotion　may　be　very　strong；　but　it　will　have　little　tendency　to　induce　movements　of　any　kind；　if　it　has　not　commonly　led　to　voluntary　action　for　its　relief　or　gratification；　and　when　movements　are　excited；　their　nature　is；　to　a　large　extent；　determined　by　those　which　have　often　and　voluntarily　been　performed　for　some　definite　end　under　the　same　emotion。　　Great　pain　urges　all　animals；　and　has　urged　them　during　endless　generations；　to　make　the　most　violent　and　diversified　efforts　to　escape　from　the　cause　of　suffering。　Even　when　a　limb　or　other　separate　part　of　the　body　is　hurt；　we　often　see　a　tendency　to　shake　it；　as　if　to　shake　off　the　cause；　though　this　may　obviously　be　impossible。　　Thus　a　habit　of　exerting　with　the　utmost　force　all　the　muscles　will　have　been　established；　whenever　great　suffering　is　experienced。　　As　the　muscles　of　the　chest　and　vocal　organs　are　habitually　used；　these　will　be　particularly　liable　to　be　acted　on；　and　loud；　harsh　screams　or　cries　will　be　uttered。　But　the　advantage　derived　from　outcries　has　here　probably　come　into　play　in　an　important　manner；　for　the　young　of　most　animals；　when　in　distress　or　danger；　call　loudly　to　their　parents　for　aid；　as　do　the　members　of　the　same　community　for　mutual　aid。


＇6＇　Muller　（‘Elements　of　Physiology；'　Eng。　　translat。　　vol。　　ii。　　p。　　932）　in　speaking　of　the　nerves；　says；　〃any　sudden　change　of　condition　of　whatever　kind　sets　the　nervous　principle　into　action。〃　　See　Virchow　and　Bernard　on　the　same　subject　in　passages　in　the　two　works　referred　to　in　my　last　foot…note。

＇7＇　H。　Spencer；　‘Essays；　Scientific；　Political；'　&c。；　Second　Series；　1863；　pp。　　109；　111。

＇8＇　Sir　H。　Holland；　in　speaking　（‘Medical　Notes　and　Reflexions；'　1839；　p。　　328）　of　that　curious　state　of　body　called　the　_fidgets_；　remarks　that　it　seems　due　to　〃an　accumulation　of　some　cause　of　irritation　which　requires　muscular　action　for　its　relief。〃

Another　principle；　namely；　the　internal　consciousness　that　the　power　or　capacity　of　the　nervous　system　is　limited；　will　have　strengthened；　though　in　a　subordinate　degree；　the　tendency　to　violent　action　under　extreme　suffering。　A　man　cannot　think　deeply　and　exert　his　utmost　muscular　force。　As　Hippocrates　long　ago　observed；　if　two　pains　are　felt　at　the　same　time；　the　severer　one　dulls　the　other。　Martyrs；　in　the　ecstasy　of　their　religious　fervour　have　often；　as　it　would　appear；　been　insensible　to　the　most　horrid　tortures。　Sailors　who　are　going　to　be　flogged　sometimes　take　a　piece　of　lead　into　their　mouths；　in　order　to　bite　it　with　their　utmost　force；　and　thus　to　bear　the　pain。　　Parturient　women　prepare　to　exert　their　muscles　to　the　utmost　in　order　to　relieve　their　sufferings。

We　thus　see　that　the　undirected　radiation　of　nerve…force　from　the　nerve…cells　which　are　first　affectedthe　long…continued　habit　of　attempting　by　struggling　to　escape　from　the　cause　of　suffering　and　the　consciousness　that　voluntary　muscular　exertion　relieves　pain；　have　all　probably　concurred　in　giving　a　tendency　to　the　most　violent；　almost　convulsive；　movements　under　extreme　suffering；　and　such　movements；　including　those　of　the　vocal　organs；　are　universally　recognized　as　highly　expressive　of　this　condition。

As　the　mere　touching　of　a　sensitive　nerve　reacts　in　a　direct　manner　on　the　heart；　severe　pain　will　obviously　react　on　it　in　like　manner；　but　far　more　energetically。　　Nevertheless；　even　in　this　case；　we　must　not　overlook　the　indirect　effects　of　habit　on　the　heart；　as　we　shall　see　when　we　consider　the　signs　of　rage。

When　a　man　suffers　from　an　agony　of　pain；　the　perspiration　often　trickles　down　his　face；　and　I　have　been　assured　by　a　veterinary　surgeon　that　he　has　frequently　seen　drops　falling　from　the　belly　and　running　down　the　inside　of　the　thighs　of　horses；　and　from　the　bodies　of　cattle；　when　thus　suffering。　He　has　observed　this；　when　there　has　been　no　struggling　which　would　account　for　the　perspiration。　　The　whole　body　of　the　female　hippopotamus；　before　alluded　to；　was　covered　with　red…coloured　perspiration　whilst　giving　birth　to　her　young。　So　it　is　with　extreme　fear；　the　same　veterinary　has　often　seen　horses　sweating　from　this　cause；　as　has　Mr。　Bartlett　with　the　rhinoceros；　and　with　man　it　is　a　well…known　symptom。　The　cause　of　perspiration　bursting　forth　in　these　cases　is　quite　obscure；　but　it　is　thought　by　some　physiologists　to　be　connected　with　the　failing　power　of　the　capillary　circulation；　and　we　know　that　the　vasomotor　system；　which　regulates　the　capillary　circulation；　is　much　influenced　by　the　mind。　With　resp