a history of science-4-第50部分

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ner　fibrils　had　not　been　rendered　visible　by　any　previous　method　of　treatment。　Golgi　himself　proved　that　the　set　of　fibrils　known　as　protoplasmic　prolongations　terminate　by　free　extremities；　and　have　no　direct　connection　with　any　cell　save　the　one　from　which　they　spring。　He　showed　also　that　the　axis　cylinders　give　off　multitudes　of　lateral　branches　not　hitherto　suspected。　　But　here　he　paused；　missing　the　real　import　of　the　discovery　of　which　he　was　hard　on　the　track。　　It　remained　for　the　Spanish　histologist　Dr。　S。　Ramon　y　Cajal　to　follow　up　the　investigation　by　means　of　an　improved　application　of　Golgi's　method　of　staining；　and　to　demonstrate　that　the　axis　cylinders；　together　with　all　their　collateral　branches；　though　sometimes　extending　to　a　great　distance；　yet　finally　terminate；　like　the　other　cell　prolongations；　in　arborescent　fibrils　having　free　extremities。　　In　a　word；　it　was　shown　that　each　central　nerve　cell；　with　its　fibrillar　offshoots；　is　an　isolated　entity。　Instead　of　being　in　physical　connection　with　a　multitude　of　other　nerve　cells；　it　has　no　direct　physical　connection　with　any　other　nerve　cell　whatever。

When　Dr。　Cajal　announced　his　discovery；　in　1889；　his　revolutionary　claims　not　unnaturally　amazed　the　mass　of　histologists。　　There　were　some　few　of　them；　however；　who　were　not　quite　unprepared　for　the　revelation；　in　particular　His；　who　had　half　suspected　the　independence　of　the　cells；　because　they　seemed　to　develop　from　dissociated　centres；　and　Forel；　who　based　a　similar　suspicion　on　the　fact　that　he　had　never　been　able　actually　to　trace　a　fibre　from　one　cell　to　another。　These　observers　then　came　readily　to　repeat　Cajal's　experiments。　So　also　did　the　veteran　histologist　Kolliker；　and　soon　afterwards　all　the　leaders　everywhere。　　The　result　was　a　practically　unanimous　confirmation　of　the　Spanish　histologist's　claims；　and　within　a　few　months　after　his　announcements　the　old　theory　of　union　of　nerve　cells　into　an　endless　mesh…work　was　completely　discarded；　and　the　theory　of　isolated　nerve　elementsthe　theory　of　neurons；　as　it　came　to　be　calledwas　fully　established　in　its　place。

As　to　how　these　isolated　nerve　cells　functionate；　Dr。　Cajal　gave　the　clew　from　the　very　first；　and　his　explanation　has　met　with　universal　approval。

In　the　modified　view；　the　nerve　cell　retains　its　old　position　as　the　storehouse　of　nervous　energy。　　Each　of　the　filaments　jutting　out　from　the　cell　is　held；　as　before；　to　be　indeed　a　transmitter　of　impulses；　but　a　transmitter　that　operates　intermittently；　like　a　telephone　wire　that　is　not　always　〃connected；〃　and；　like　that　wire；　the　nerve　fibril　operates　by　contact　and　not　by　continuity。　　Under　proper　stimulation　the　ends　of　the　fibrils　reach　out；　come　in　contact　with　other　end　fibrils　of　other　cells；　and　conduct　their　destined　impulse。　　Again　they　retract；　and　communication　ceases　for　the　time　between　those　particular　cells。　Meantime；　by　a　different　arrangement　of　the　various　conductors；　different　sets　of　cells　are　placed　in　communication；　different　associations　of　nervous　impulses　induced；　different　trains　of　thought　engendered。　Each　fibril　when　retracted　becomes　a　non…conductor；　but　when　extended　and　in　contact　with　another　fibril；　or　with　the　body　of　another　cell；　it　conducts　its　message　as　readily　as　a　continuous　filament　could　doprecisely　as　in　the　case　of　an　electric　wire。

This　conception；　founded　on　a　most　tangible　anatomical　basis；　enables　us　to　answer　the　question　as　to　how　ideas　are　isolated；　and　also；　as　Dr。　Cajal　points　out；　throws　new　light　on　many　other　mental　processes。　　One　can　imagine；　for　example；　by　keeping　in　mind　the　flexible　nerve　prolongations；　how　new　trains　of　thought　may　be　engendered　through　novel　associations　of　cells；　how　facility　of　thought　or　of　action　in　certain　directions　is　acquired　through　the　habitual　making　of　certain　nerve…cell　connections；　how　certain　bits　of　knowledge　may　escape　our　memory　and　refuse　to　be　found　for　a　time　because　of　a　temporary　incapacity　of　the　nerve　cells　to　make　the　proper　connections；　and　so　on　indefinitely。

If　one　likens　each　nerve　cell　to　a　central　telephone　office；　each　of　its　filamentous　prolongations　to　a　telephone　wire；　one　can　imagine　a　striking　analogy　between　the　modus　operandi　of　nervous　processes　and　of　the　telephone　system。　The　utility　of　new　connections　at　the　central　office；　the　uselessness　of　the　mechanism　when　the　connections　cannot　be　made；　the　〃wires　in　use〃　that　retard　your　message；　perhaps　even　the　crossing　of　wires；　bringing　you　a　jangle　of　sounds　far　different　from　what　you　desireall　these　and　a　multiplicity　of　other　things　that　will　suggest　themselves　to　every　user　of　the　telephone　may　be　imagined　as　being　almost　ludicrously　paralleled　in　the　operations　of　the　nervous　mechanism。　And　that　parallel；　startling　as　it　may　seem；　is　not　a　mere　futile　imagining。　　It　is　sustained　and　rendered　plausible　by　a　sound　substratum　of　knowledge　of　the　anatomical　conditions　under　which　the　central　nervous　mechanism　exists；　and　in　default　of　which；　as　pathology　demonstrates　with　no　less　certitude；　its　functionings　are　futile　to　produce　the　normal　manifestations　of　higher　intellection。



X。　THE　NEW　SCIENCE　OF　ORIENTAL　ARCHAEOLOGY

HOW　THE　〃RIDDLE　OF　THE　SPHINX〃　WAS　READ

Conspicuously　placed　in　the　great　hall　of　Egyptian　antiquities　in　the　British　Museum　is　a　wonderful　piece　of　sculpture　known　as　the　Rosetta　Stone。　　I　doubt　if　any　other　piece　in　the　entire　exhibit　attracts　so　much　attention　from　the　casual　visitor　as　this　slab　of　black　basalt　on　its　telescope…like　pedestal。　　The　hall　itself；　despite　its　profusion　of　strangely　sculptured　treasures；　is　never　crowded；　but　before　this　stone　you　may　almost　always　find　some　one　standing；　gazing　with　more　or　less　of　discernment　at　the　strange　characters　that　are　graven　neatly　across　its　upturned；　glass…protected　face。　A　glance　at　this　graven　surface　suffices　to　show　that　three　sets　of　inscriptions　are　recorded　there。　　The　upper　one；　occupying　about　one…fourth　of　the　surface；　is　a　pictured　scroll；　made　up　of　chains　of　those　strange　outlines　of　serpents；　hawks；　lions；　and　so　on；　which　are　recognized；　even　by　the　least　initiated；　as　hieroglyphics。　The　middle　inscription；　made　up　of　lines；　angles；　and　half…pictures；　one　might　surmise　to　be　a　sort　of　abbreviated　or　short…hand　hieroglyphic。　The　third　or　lower　inscription　is　Greekobviously　a　thing　of　words。　If　the　screeds　above　be　also　made　of　words；　only　the　elect　have　any　way　of　proving　the　fact。

Fortunately；　however；　even　the　least　scholarly　observer　is　left　in　no　doubt　as　to　the　real　import　of　the　thing　he　sees；　for　an　obliging　English　label　tells　us　that　these　three　inscriptions　are　renderings　of　the　same　message；　and　that　this　message　is　a　〃decree　of　the　priests　of　Memphis　conferring　divine　honors　on　Ptolemy　V。　（Epiphenes）；　King　of　Egypt；　B。C。　195。〃　The　label　goes　on　to　state　that　the　upper　inscription　（of　which；　unfortunately；　only　part　of　the　last　dozen　lines　or　so　remains；　the　slab　being　broken）　is　in　〃the　Egyptian　language；　in　hieroglyphics；　or　writing　of　the　priests〃；　the　second　inscription　〃in　the　same　language　is　in　Demotic；　or　the　writing　of　the　people〃；　and　the　third　〃the　Greek　language　and　character。〃　　Following　this　is　a　brief　biography　of　the　Rosetta　Stone　itself；　as　follows：　〃The　stone　was　found　by　the　French　in　1798　among　the　ruins　of　Fort　Saint　Julien；　near　the　Rosetta　mouth　of　the　Nile。　　It　passed　into　the　hands　of　the　British　by　the　treaty　of　Alexandria；　and　was　deposited　in　the　British　Museum　in　the　year　1801。〃　There　is　a　whole　volume　of　history　in　that　brief　inscriptionand　a　bitter　sting　thrown　in；　if　the　reader　chance　to　be　a　Frenchman。　　Yet　the　facts　involved　could　scarcely　be　suggested　more　modestly。　　They　are　recorded　much　more　bluntly　in　a　graven　inscription　on　the　side　of　the　stone；　which　reads：　〃Captured　in　Egypt　by　the　British　Army；　1801。〃　No　Frenchman　could　read　those　words　without　a　veritable　sinking　of　the　heart。

The　value　of　the　Rosetta　Stone　depended　on　the　fact　that　it　gave　promise；　even　when　casually　inspected；　of　furnishing　a　key　to　the　centuries…old　mystery　of　the　hieroglyphics。　　For　two　thousand　years　the　secret　of　these　strange　markings　had　been　forgotten。　Nowhere　in　the　worldquite　as　little　in　Egypt　as　elsewherehad　any　man　the　slightest　clew　to　their　meaning；　there　were　those　who　even　doubted　whether　these　droll　picturings　really　had　any　specific　meaning；　questioning　whether　they　were　not　rather　vague　symbols　of　esoteric　religious　import　and　nothing　more。　And　it　was　the　Rosetta　Stone　that　gave　the　answer　to　these　doubters　and　restored　to　the　world　a　lost　language　and　a　forgotten　literature。

The　trustees　of　the　museum　recognized　at　once　that　the　problem　of　the　Rosetta　Stone　was　one　on　which　the　scientists　of　the　world　might　well　exhaust　their　ingenuity；　and　promptly　published　to　the　world　a　carefully　lithographed　copy　of　the　entire　inscription；　so　that　foreign　scholarship　had　equal　opportunity　with　the　British　to　try　at　the　riddle。　It　was　an　Englishman；　however；　who　first　gained　a　clew　to　the　solution。　This　was　none　other　than　the　extraordinary　Dr。　Thomas　Young；　the　demonstrator　of　the　vibratory　nature　of　light。

Young's　specific　discoveries　were　these：　（1）　That　many　of　the　pictures　of