the origin and nature of emotions-第19章

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ure　be　low；　there　will　be　a　permanent　loss　of　some　of　the　brain…cells。　This　explains　why　an　individual　who　has　suffered　from　a　prolonged　hemorrhage　will　never　again　be　restored　to　his　original　powers。

Drugs。According　to　their　effect　upon　the　brain…cells；　drugs　may　be　divided　into　three　classes：　　First；　those　that　stimulate　the　brain…cells　to　increased　activity；　as　strychnin　（Fig。　37）；　second；　those　that　chemically　destroy　the　brain…cells；　as　alcohol　and　iodoform　（Figs。　38　and　39）；　third；　those　that　suspend　the　functions　of　the　cells　without　damaging　them；　as　nitrous　oxid；　ether；　morphin。　Our　experiments　have　shown　that　the　brain…cell　changes　induced　by　drugs　of　the　first　class　are　precisely　the　same　as　the　cycle　of　changes　produced　by　the　emotions　and　by　physical　activity。　We　have　found　that　strychnin；　according　to　the　dosage；　causes　convulsions　ending　in　exhaustion　and　death；　excitation　followed　by　lassitude；　stimulation　without　notable　after…results；　or


｛illust。　caption　=　A；　Section　of　Cerebellum　of　Normal　Dog。　　C；　Section　of　Cerebellum　of　Dog　after　Repeated　Doses　of　Strychnin。　　FIG。　　37。　BRAIN…CELLS　SHOWING　STAGE　OF　HYPERCHROMATISM　FOLLOWED　BY　CHROMATOLYSIS　RESULTING　FROM　THE　CONTINUATION　OF　THE　STIMULUS。　　（Camera　lucida　drawings。）increased　mental　tone；　while　the　brain…cells　accurately　display　these　physiologic　alterations　in　proportional　hyperchromatism　in　the　active　stages；　and　proportional　chromatolysis　in　the　stages　of　reaction。　　The　biologic　and　therapeutic　application　of　this　fact　is　as　obvious　as　it　is　important。

In　our　experiments；　alcohol　in　large　and　repeated　dosage　caused　marked　morphologic　changes　in　the　brain…cells　which　went　as　far　even　as　the　destruction　of　some　of　the　cells　（Fig。　39）。　Ether；　on　the　other　hand；　even　after　five　hours　of　administration；　produced　no　observable　destructive　changes　in　the　brain…cells。

The　effect　of　iodoform　was　peculiarly　interesting；　as　it　was　the　only　drug　that　produced　a　rise　of　temperature。　　Its　observed　effect　upon　the　brain…cells　was　that　of　wide…spread　destruction。

Infections。In　every　observation　regarding　the　effect　of　pyogenic　infections　on　dogs　and　on　man　we　found　that　they　caused　definite　and　demonstrable　lesions　in　certain　cells　of　the　nervous　system；　the　most　marked　changes　being　in　the　cortex　and　the　cerebellum　（Fig。　40）。　For　example；　in　fatal　infections　resulting　from　bowel　obstruction；　in　peritonitis；　and　in　osteomyelitis；　the　real　lesion　is　in　the　brain…cells。　We　may；　therefore；　reasonably　conclude　that　the　lassitude；　the　diminished　mental　power；　the　excitability；　irritability；　restlessness；　delirium；　and　unconsciousness　which　may　be　associated　with　acute　infections；　are　due　to　physical　changes　in　the　brain…cells。

Graves'　Disease。In　Graves'　disease　the　brain…cells　show　marked　changes　which　are　apparently　the　same　as　those　produced　by　overwork；　by　the　emotions；　and　by　strychnin。　　In　the　postmortem　examination　of　one　advanced　case　it　was　found　that　a　large　number　of　brain…cells　were　disintegrated　beyond　the　power　of　recuperation；　even　had　the　patient　lived。　　This　is　undoubtedly　the　reason　why　a　severe　case　of　exophthalmic　goiter　sustains　a　permanent　loss　of　brain　power。

Insomnia。The　brains　of　rabbits　which　had　been　kept　awake　for　one　hundred　hours　showed　precisely　the　same　changes　as　those　shown　in　physical　fatigue；　strychnin　poisoning；　and　exhaustion　from　emotional　stimulation。　　Eight　hours　of　continuous　sleep　restored　all　the　cells　except　those　that　had　been　completely　exhausted。　This　will　explain　the　permanent　ill　effect　of　long…continued　insomnia；　that　is；　long…continued　insomnia　permanently　destroys　a　part　of　the　brain…cells　just　as　do　too　great　physical　exertion；　certain　drugs；　emotional　strain；　exophthalmic　goiter；　and　hemorrhage。　We　found；　however；　that　if；　instead　of　natural　sleep；　the　rabbits　were　placed　for　the　same　number　of　hours　under　nitrous　oxid　anesthesia；　not　only　did　the　brain…cells　recover　from　the　physical　deterioration；　but　that　90　per　cent。　　of　them　became　hyperchromatic。　This　gives　us　a　possible　clue　to　the　actual　chemical　effect　of　sleep。　For　since　nitrous　oxid　owes　its　anesthetic　effect　to　its　influence　upon　oxidation；　we　may　infer　that　sleep　also　retards　the　oxidation　of　the　cell　contents。　　If　this　be　true；　then　it　is　probable　that　inhalation　anesthetics　exert　their　peculiar　influence　upon　that　portion　of　the　brain　through　which　sleep　itself　is　produced。　If　nitrous　oxid　anesthesia　and　sleep　are　chemically　identical；　then　we　have　a　further　clue　to　one　of　the　primary　mechanisms　of　life　itself；　and　as　a　practical　corollary　one　might　be　able　to　produce　artificial　sleep　which　would　closely　resemble　normal　sleep；　but　which　would　have　this　advantage；　that　by　using　an　anesthetic　which　interferes　with　oxidation　the　brain…cells　might　be　reconstructed　after　physical　fatigue；　after　emotional　strain；　or　after　the　depression　of　disease。

In　the　case　of　the　rabbit　in　which　nitrous　oxid　was　substituted　for　sleep；　the　appearance　of　the　brain…cells　resembled　that　in　but　one　other　group　experimentally　examinedthe　brain…cells　of　hibernating　woodchucks。

Insanity。Our　researches　have　shown　that　in　the　course　of　a　fatal　disease　and　in　fatal　exhaustion；　however　produced；　death　does　not　ensue　until　there　is　marked　disorganization　of　the　brain　tissue。　In　the　progress　of　disease　or　exhaustion　one　may　see　in　different　patients　every　outward　manifestation　of　mental　deterioration；　manifestations　which；　in　a　person　who　does　not　show　any　other　sign　of　physical　disease；　mark　him　as　insane。　　Take；　for　example；　the　progressive　mental　state　of　a　brilliant　scholar　suffering　from　typhoid　fever。　On　the　first　day　of　the　gradual　onset　of　the　disease　he　would　notice　that　his　mental　power　was　below　its　maximum　efficiency；　on　the　second　he　would　notice　a　further　deterioration；　and　so　the　mental　effect　of　his　disease　would　progress　until　he　would　find　it　impossible　to　express　a　thought　or　to　make　a　deduction。　No　one　can　be　philanthropic　with　jaundice；　no　one　suffering　from　Graves'　disease　can　be　generous；　no　mental　process　is　possible　in　the　course　of　the　acute　infectious　diseases。　　Just　prior　to　death　from　any　cause　every　one　is　in　a　mental　state　which；　if　it　could　be　continued；　would　cause　that　individual　to　be　judged　insane。　If　the　delirium　that　occurs　in　the　course　of　certain　diseases　should　be　continued；　the　patient　would　be　judged　insane。　In　severe　cases　of　Graves'　disease　the　patient　is　insane。　Individuals　under　overwhelming　emotion　may　be　temporarily　insane。　Every　clinician　has　seen　great　numbers　of　cases　in　which　insanity　is　a　phase　of　a　disease；　of　an　injury；　or　of　an　emotion。　The　stage　of　excitation　in　anesthesia　is　insanity。　The　only　difference　between　what　is　conventionally　called　insanity　and　the　fleeting　insanity　of　the　sick　and　the　injured　is　that　of　time。　We　may　conclude；　therefore；　what　must　be　the　brain…picture　of　the　person　who　is　permanently　insane。　　This　_a　priori_　reasoning　is　all　that　is　possible；　since　the　study　of　the　brain　in　the　insane　has　thus　far　been　confined　to　the　brains　of　those　who　have　died　of　some　disease。　And　it　is　impossible　to　say　which　changes　have　been　produced　by　the　fatal　disease；　and　which　by　the　condition　which　produced　the　insanity。　The　only　logical　way　by　which　to　investigate　the　physical　basis　of　insanity　would　be　to　make　use　of　the　very　rare　opportunities　of　studying　the　brains　of　insane　persons　who　have　died　in　accidents。

Our　experiments　have　proved　conclusively　that　whether　we　call　a　person　fatigued　or　diseased；　the　brain…cells　undergo　physical　deterioration；　accompanied　by　loss　of　mental　power　（Figs。　40　to　43）。　Even　to　the　minutest　detail　we　can　show　a　direct　relationship　between　the　physical　state　of　the　brain…cells　and　the　mental　power　of　the　individual；　that　is；　the　physical　power　of　a　person　goes　_pari　passu_　with　his　mental　power。　Indeed；　it　is　impossible　to　conceive　how　any　mental　action；　however　subtle；　can　occur　without　a　corresponding　change　in　the　brain…cells。　It　is　possible　now　to　measure　only　the　evidences　of　the　effects　on　the　brain…cells　of　gross　and　violent　mental　activity。　At　some　future　time　it　will　doubtless　be　possible　so　to　refine　the　technic　of　brain…cell　examinations　that　more　subtle　chan