the origin and nature of emotions-第24部分

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rain　receiving　adrenalin；　while　the　brain　receiving　no　adrenalin　showed　no　change。　Here　is　a　clear…cut　observation　on　the　action　of　adrenalin　on　the　brain；　for　both　the　functional　and　the　histologic　tests　showed　that　adrenalin　causes　increased　brain　action。　The　significance　of　this　affinity　of　the　brain　for　adrenalin　begins　to　be　seen　when　I　call　attention　to　the　following　striking　facts：

1。　　Adrenalin　alone　causes　hyperchromatism　followed　by　chromatolysis；　and　in　overdosage　causes　the　destruction　of　some　brain…cells。

2。　　When　both　adrenal　glands　are　excised　and　no　other　factor　is　introduced；　the　Nissl　substance　progressively　disappears　from　the　brain…cells　until　death。　　This　far…reaching　point　will　be　taken　up　later　（Fig。　60）。

Here　our　purpose　is　to　discuss　the　cause　of　the　brain…cell　changes。　We　have　seen　that　in　crossed　brain　and　body　circulation　trauma　causes　changes　in　the　cells　of　the　brain　which　is　disconnected　from　the　traumatized　body　by　its　circulation；　but　which　is　connected　with　the　traumatized　body　by　the　nervous　system。　We　have　seen　that　adrenalin　causes　activation　of　the　body　connected　with　its　brain　by　the　nervous　system；　and　histologic　changes　in　the　brain　acted　on　directly　by　the　adrenalin；　but　we　found　no　notable　brain…cell　changes　in　the　other　brain　through　which　the　products　of　metabolism　have　circulated。

In　the　foregoing　we　find　direct　evidence　that　the　products　of　metabolism　are　not　the　principal　cause　of　the　brain…cell　changes。　We　shall　now　present　evidence　to　show　that　for　the　most　part　the　brain…cell　changes　are　〃work〃　changes。　　What　work？　　We　postulate　that　it　is　the　work　by　which　the　energy　stored　in　the　brain…cells　is　converted　into　electricity　or　some　other　form　of　transmissible　energy　which　then　activates　certain　glands　and　muscles；　thus　converting　latent　energy　into　beat　and　motion。　　It　has　chanced　that　certain　other　studies　have　given　an　analogous　and　convincing　proof　of　this　postulate。　In　the　electric　fish　a　part　of　the　muscular　mechanism　is　replaced　by　a　specialized　structure　for　storing　and　discharging　electricity。　We　found　〃work〃　changes　in　the　brain…cells　of　electric　fish　after　all　their　electricity　had　been　rapidly　discharged　（Fig。　61）。　We　found　further　that　electric　fish　could　not　discharge　their　electricity　when　under　anesthesia；　and　clinically　we　know　that　under　deep　morphin　narcosis；　and　under　anesthesia；　the　production　both　of　heat　and　of　muscular　action　is　hindered。　The　action　of　morphin　in　lessening　fever　production　is　probably　the　result　of　its　depressing　influence　on　the　brain…cells；　because　of　which　a　diminished　amount　of　their　potential　energy　is　converted　into　electricity　and　a　diminished　electric　discharge　from　the　brain　to　the　muscles　should　diminish　heat　production　proportionally。　We　found　by　experiment　that　under　deep　morphinization　brain…cell　changes　due　to　toxins　could　be　largely　prevented　（Fig。　62）；　in　human　patients　deep　morphinization　diminishes　the　production　of　muscular　action　and　of　fever　and　conserves　life　when　it　is　threatened　by　acute　infections。　　The　contribution　of　the　brain…cells　to　the　production　of　heat　is　either　the　result　of　the　direct　conversion　of　their　stored　energy　into　heat；　or　of　the　conversion　of　their　latent　energy　into　electricity　or　a　similar　force；　which　in　turn　causes　certain　glands　and　muscles　to　convert　latent　energy　into　heat。

A　further　support　to　the　postulate　that　the　brain…cells　contribute　to　the　production　of　fever　by　sending　impulses　to　the　muscles　is　found　in　the　effect　of　muscular　exertion；　or　of　other　forms　of　motor　stimulation；　in　the　presence　of　a　fever…producing　infection。　Under　such　circumstances　muscular　exertion　causes　additional　fever；　and　causes　also　added　but　identical　changes　in　the　brain…cells。　Thyroid　extract　and　iodin　have　the　same　effect　as　muscular　exertion　and　infection　in　the　production　of　fever　and　the　production　of　brain…cell　changes。　All　this　evidence　is　a　strong　argument　in　favor　of　the　theory　that　certain　constituents　of　the　brain…cells　are　consumed　in　the　work　performed　by　the　brain　in　the　production　of　fever。

That　the　stimulation　of　the　brain…cells　without　gross　activity　of　the　skeletal　muscles　and　without　infection　can　produce　heat　is　shown　as　follows：

（_a_）　Fever　is　produced　when　animals　are　subjected　to　fear　without　any　consequent　exertion　of　the　skeletal　muscles。

（_b_）　The　temperature　of　the　anxious　friends　of　patients　will　rise　while　they　await　the　outcome　of　an　operation　（Fig。　63）。

（_c_）　The　temperature　and　pulse　of　patients　will　rise　as　a　result　of　the　mere　anticipation　of　a　surgical　operation　（Fig。　64）。

（_d_）　There　are　innumerable　clinical　observations　as　to　the　effect　of　emotional　excitation　on　the　temperature　of　patients。　A　rise　of　a　degree　or　more　is　a　common　result　of　a　visit　from　a　tactless　friend。　　There　is　a　traditional　Sunday　increase　of　temperature　in　hospital　wards。　　Now　the　visitor　does　not　bring　and　administer　more　infection　to　the　patient　to　cause　this　rise；　and　the　rise　of　temperature　occurs　even　if　the　patient　does　not　make　the　least　muscular　exertion　as　a　result　of　the　visit。　I　once　observed　an　average　increase　of　one　and　one…eighth　degrees　of　temperature　in　a　ward　of　fifteen　children　as　a　result　of　a　Fourth　of　July　celebration。

Is　the　contribution　of　the　brain　to　the　production　of　heat　due　to　the　conversion　of　latent　energy　directly　into　heat；　or　does　the　brain　produce　heat　principally　by　converting　its　latent　energy　into　electricity　or　some　similar　form　of　transmissible　energy　which；　through　nerve　connections；　stimulates　other　organs　and　tissues；　which　in　turn　convert　their　stores　of　latent　energy　into　heat？

According　to　Starling；　when　the　connection　between　the　brain　and　the　muscles　of　an　animal　is　severed　by　curare；　by　anesthetics；　by　the　division　of　the　cord　and　nerves；　then　the　heat…producing　power　of　the　animal　so　modified　is　on　a　level　with　that　of　cold…blooded　animals。　With　cold　the　temperature　falls；　with　heat　it　rises。　　Such　an　animal　has　no　more　control　over　the　conversion　of　latent　energy　into　heat　than　it　has　over　the　conversion　of　latent　energy　into　motion。

Electric　stimulation　done　over　a　period　of　time　causes　brain…cell　changes；　and　electric　stimulation　of　the　muscles　causes　a　rise　in　temperature。


Summary　of　Brain…cell　Studies

In　our　crossed　circulation　experiments　we　found　that　neither　waste　products　nor　metabolic　poisons　could　be　considered　the　principal　cause　of　the　brain…cell　changes。　　We　found　that　in　the　production　both　of　muscular　action　and　of　fever　there　were　brain…cell　changes　which　showed　a　quantita…tive　relation　to　the　temperature　changes　or　to　the　muscular　work　done。　　We　observed　that　under　deep　morphinization　the　febrile　response　or　the　muscular　work　done　was　either　diminished　or　eliminated　and　that　the　brain…cell　changes　were　correspondingly　diminished　or　eliminated。　　We　found　also　that　brain…cell　changes　and　muscular　work　followed　electric　stimulation　alone。　I　conclude；　therefore；　that　the　brain…cell　changes　are　work　changes。

We　shall　next　consider　other　organs　of　the　kinetic　system　in　their　relation　to　muscular　activity；　to　emotion；　to　consciousness；　to　sleep；　to　hibernation；　and　to　heat　production。


The　Adrenals

In　our　extensive　study　of　the　brain　in　its　relation　to　the　production　of　energy　and　the　consequent　exhaustion　caused　by　fear　and　rage；　by　the　injection　of　foreign　proteins；　of　bacterial　toxins；　and　of　strychnin；　by　anaphylaxis；　by　the　injection　of　thyroid　extract；　of　adrenalin；　and　of　morphin；　we　found　that；　with　the　exception　of　morphin；　each　of　these　agents　produced　identical　changes　in　the　brain…cells。　As　we　believed　that　the　adrenals　were　intimately　associated　with　the　brain　in　its　activities；　we　concluded　that　the　adrenals　also　must　have　been　affected　by　each　of　these　agents。　To　prove　this　relation；　we　administered　the　above…mentioned　stimuli　to　animals　and　studied　their　effects　upon　the　adrenals　by　functional；　histologic；　and　surgical　methods；　the　functional　tests　being　made　by　Cannon's　method。

Functional　Study　of　the　Adrenals。Our　method　of　applying　the　Cannon　test　for　adrenalin　was　as　follows：　　（_a_）　The　blood　of　the　animals　was　tested　before　the　application　of　the　stimulus。　If　this　test　was　negative；　then　（_b_）　the　stimulus　was　applied　and　the　blood　again　tested。　　If　this　second　test　was　negative；　a　small　amount　of　adrenalin　was　added。　　If　a　positive　reaction　was　then　given；　the　negative　result　was　accepted　as　conclusive。　（_c_）　If　the　control　test　was　negative；　then　the　stimulus　was　given。　If　the　blood　after　stimulation　gave　a　positive　result　for　adrenalin；　a　second　test　of　the　same　animal's　blood　was　made　twenty…five　minutes　or　more　later。　　If　the　second　test　was　negative；　then　the　positive　result　of　the　first　test　was　accepted　as　conclusive。

We　have　recorded　66　clear…cut　experiments　on　dogs；　which　show　that　after　fear　and　rage；　after　anaphylaxis；　after　injections　of　indol　and　skatol；　of　leucin　and　creatin；　of　the　toxins　of　diphtheria　and　colon　bacilli；　of　streptococci　and　staphylococci；　of　foreign　proteins；　and　of　strychnin；　the　Cannon　test　for　adrenalin　was　positive。　The　test　was　negative　after　trauma　under　anesthesia；　and　after　intravenous　injections　of　thyroid　extract；　of　thyroglobin；　and　of　the　juices　of　various　organs　injected　into　the　same　animal　from　which　the　organs　were　taken。　　Placental　extract　gave　a　positive　test。　The　test　was　sometimes　positive　after　electric　stimulation　of　the　splanchnic　nerves。　　On　the　other　hand；　if　the　nerve　supply　to　the　adrenals　had　been　previously　divided；　or　if　the　adrenals　had　been　previously　excised；　then　the　Cannon　test　was　negative　after　the　administration　of　each　of　the　foregoing　adequate　stimuli。　Blood　taken　directly　from　the　adrenal　vein　gave　a　positive　result；　but　under　deep　morphinization　the　blood　from　the　adrenal　vein　was　negative；　and　under　deep　morphinization　the　foregoing　adequate　stimuli　were　negative。

In　brief；　the　agencies　that　in　our　brain…cell　studies　were　found　to　cause　hyperchromatism　followed　by　chromatolysis　gave　positive　results　in　the　Cannon　test　for　adrenalin　（Fig。　62）。　The　one　agent　which　was　found　to　protect　the　brain　against　changes　in　the　Nissl　substance　morphingave　a　negative　result　in　the　Cannon　test　for　adrenalin。