the rise and progress of palaeontology-第1章

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The　Rise　and　Progress　of　Palaeontology

by　Thomas　Henry　Huxley






That　application　of　the　sciences　of　biology　and　geology；　which

is　commonly　known　as　palaeontology；　took　its　origin　in　the　mind

of　the　first　person　who；　finding　something　like　a　shell；　or　a

bone；　naturally　imbedded　in　gravel　or　rock；　indulged　in

speculations　upon　the　nature　of　this　thing　which　he　had　dug　out

this　〃fossil〃and　upon　the　causes　which　had　brought　it　into

such　a　position。　In　this　rudimentary　form；　a　high　antiquity　may

safely　be　ascribed　to　palaeontology；　inasmuch　as　we　know　that；

500　years　before　the　Christian　era；　the　philosophic　doctrines　of

Xenophanes　were　influenced　by　his　observations　upon　the　fossil

remains　exposed　in　the　quarries　of　Syracuse。　From　this　time

forth　not　only　the　philosophers；　but　the　poets；　the　historians；

the　geographers　of　antiquity　occasionally　refer　to　fossils；

and；　after　the　revival　of　learning；　lively　controversies　arose

respecting　their　real　nature。　But　hardly　more　than　two　centuries

have　elapsed　since　this　fundamental　problem　was　first

exhaustively　treated；　it　was　only　in　the　last　century　that　the

archaeological　value　of　fossilstheir　importance；　I　mean；　as

records　of　the　history　of　the　earthwas　fully　recognised；

the　first　adequate　investigation　of　the　fossil　remains　of　any

large　group　of　vertebrated　animals　is　to　be　found　in　Cuvier's

〃Recherches　sur　les　Ossemens　Fossiles；〃　completed　in　1822；

and；　so　modern　is　stratigraphical　palaeontology；　that　its

founder；　William　Smith；　lived　to　receive　the　just　recognition　of

his　services　by　the　award　of　the　first　Wollaston　Medal　in　1831。



But；　although　palaeontology　is　a　comparatively　youthful

scientific　speciality；　the　mass　of　materials　with　which　it　has

to　deal　is　already　prodigious。　In　the　last　fifty　years　the

number　of　known　fossil　remains　of　invertebrated　animals　has　been

trebled　or　quadrupled。　The　work　of　interpretation　of　vertebrate

fossils；　the　foundations　of　which　were　so　solidly　laid　by

Cuvier；　was　carried　on；　with　wonderful　vigour　and　success；　by

Agassiz　in　Switzerland；　by　Von　Meyer　in　Germany；　and　last；　but

not　least；　by　Owen　in　this　country；　while；　in　later　years；　a

multitude　of　workers　have　laboured　in　the　same　field。　In　many

groups　of　the　animal　kingdom　the　number　of　fossil　forms　already

known　is　as　great　as　that　of　the　existing　species。　In　some　cases

it　is　much　greater；　and　there　are　entire　orders　of　animals　of

the　existence　of　which　we　should　know　nothing　except　for　the

evidence　afforded　by　fossil　remains。　With　all　this　it　may　be

safely　assumed　that；　at　the　present　moment；　we　are　not

acquainted　with　a　tittle　of　the　fossils　which　will　sooner　or

later　be　discovered。　If　we　may　judge　by　the　profusion　yielded

within　the　last　few　years　by　the　Tertiary　formations　of　North

America；　there　seems　to　be　no　limit　to　the　multitude　of

mammalian　remains　to　be　expected　from　that　continent；

and　analogy　leads　us　to　expect　similar　riches　in　Eastern　Asia；

whenever　the　Tertiary　formations　of　that　region　are　as　carefully

explored。　Again；　we　have；　as　yet；　almost　everything　to　learn

respecting　the　terrestrial　population　of　the　Mesozoic　epoch；

and　it　seems　as　if　the　Western　territories　of　the　United　States

were　about　to　prove　as　instructive　in　regard　to　this　point　as

they　have　in　respect　of　tertiary　life。　My　friend　Professor　Marsh

informs　me　that；　within　two　years；　remains　of　more　than　160

distinct　individuals　of　mammals；　belonging　to　twenty　species　and

nine　genera；　have　been　found　in　a　space　not　larger　than　the

floor　of　a　good…sized　room；　while　beds　of　the　same　age　have

yielded　300　reptiles；　varying　in　size　from　a　length　of　60　feet

or　80　feet　to　the　dimensions　of　a　rabbit。



The　task　which　I　have　set　myself　to…night　is　to　endeavour　to　lay

before　you；　as　briefly　as　possible；　a　sketch　of　the　successive

steps　by　which　our　present　knowledge　of　the　facts　of

palaeontology　and　of　those　conclusions　from　them　which　are

indisputable；　has　been　attained；　and　I　beg　leave　to　remind　you；

at　the　outset；　that　in　attempting　to　sketch　the　progress　of　a

branch　of　knowledge　to　which　innumerable　labours　have

contributed；　my　business　is　rather　with　generalisations　than

with　details。　It　is　my　object　to　mark　the　epochs　of

palaeontology；　not　to　recount　all　the　events　of　its　history。



That　which　I　just　now　called　the　fundamental　problem　of

palaeontology；　the　question　which　has　to　be　settled　before　any

other　can　be　profitably　discussed；　is　this；　What　is　the　nature

of　fossils？　Are　they；　as　the　healthy　common　sense　of　the　ancient

Greeks　appears　to　have　led　them　to　assume　without　hesitation；

the　remains　of　animals　and　plants？　Or　are　they；　as　was　so

generally　maintained　in　the　fifteenth；　sixteenth；　and

seventeenth　centuries；　mere　figured　stones；　portions　of　mineral

matter　which　have　assumed　the　forms　of　leaves　and　shells　and

bones；　just　as　those　portions　of　mineral　matter　which　we　call

crystals　take　on　the　form　of　regular　geometrical　solids？

Or；　again；　are　they；　as　others　thought；　the　products　of　the

germs　of　animals　and　of　the　seeds　of　plants　which　have　lost

their　way；　as　it　were；　in　the　bowels　of　the　earth；　and　have

achieved　only　an　imperfect　and　abortive　development？　It　is　easy

to　sneer　at　our　ancestors　for　being　disposed　to　reject　the　first

in　favour　of　one　or　other　of　the　last　two　hypotheses；　but　it　is

much　more　profitable　to　try　to　discover　why　they；　who　were

really　not　one　whit　less　sensible　persons　than　our　excellent

selves；　should　have　been　led　to　entertain　views　which　strike　us

as　absurd；　The　belief　in　what　is　erroneously　called　spontaneous

generation；　that　is　to　say；　in　the　development　of　living　matter

out　of　mineral　matter；　apart　from　the　agency　of　pre…existing

living　matter；　as　an　ordinary　occurrence　at　the　present　day

which　is　still　held　by　some　of　us；　was　universally　accepted　as

an　obvious　truth　by　them。　They　could　point　to　the　arborescent

forms　assumed　by　hoar…frost　and　by　sundry　metallic　minerals　as

evidence　of　the　existence　in　nature　of　a　〃plastic　force〃

competent　to　enable　inorganic　matter　to　assume　the　form　of

organised　bodies。　Then；　as　every　one　who　is　familiar　with

fossils　knows；　they　present　innumerable　gradations；　from　shells

and　bones　which　exactly　resemble　the　recent　objects；　to　masses

of　mere　stone　which；　however　accurately　they　repeat　the　outward

form　of　the　organic　body；　have　nothing　else　in　common　with　it；

and；　thence；　to　mere　traces　and　faint　impressions　in　the

continuous　substance　of　the　rock。　What　we　now　know　to　be　the

results　of　the　chemical　changes　which　take　place　in　the　course

of　fossilisation；　by　which　mineral　is　substituted　for　organic

substance；　might；　in　the　absence　of　such　knowledge；　be　fairly

interpreted　as　the　expression　of　a　process　of　development　in　the

opposite　directionfrom　the　mineral　to　the　organic。　Moreover；

in　an　age　when　it　would　have　seemed　the　most　absurd　of　paradoxes

to　suggest　that　the　general　level　of　the　sea　is　constant；　while

that　of　the　solid　land　fluctuates　up　and　down　through　thousands

of　feet　in　a　secular　ground　swell；　it　may　well　have　appeared　far

less　hazardous　to　conceive　that　fossils　are　sports　of　nature

than　to　accept　the　necessary　alternative；　that　all　the　inland

regions　and　highlands；　in　the　rocks　of　which　marine　shells　had

been　found；　had　once　been　covered　by　the　ocean。　It　is　not　so

surprising；　therefore；　as　it　may　at　first　seem；　that　although

such　men　as　Leonardo　da　Vinci　and　Bernard　Palissy　took　just

views　of　the　nature　of　fossils；　the　opinion　of　the　majority　of

their　contemporaries　set　strongly　the　other　way；　nor　even　that

error　maintained　itself　long　after　the　scientific　grounds　of　the

true　interpretation　of　fossils　had　been　stated；　in　a　manner　that

left　nothing　to　be　desired；　in　the　latter　half　of　the

seventeenth　century。　The　person　who　rendered　this　good　service

to　palaeontology　was　Nicolas　Steno；　professor　of　anatomy　in

Florence；　though　a　Dane　by　birth。　Collectors　of　fossils　at　that

day　were　familiar　with　certain　bodies　termed　〃glossopetrae；〃　and

speculation　was　rife　as　to　their　nature。　In　the　first　half　of

the　seventeenth　century；　Fabio　Colonna　had　tried　to　convince　his

colleagues　of　the　famous　Accademia　dei　Lincei　that　the

glossopetrae　were　merely　fossil　sharks'　teeth；　but　his　arguments

made　no　impression。　Fifty　years　later；　Steno　re…opened　the

question；　and；　by　dissecting　the　head　of　a　shark　and　pointing

out　the　very　exact　correspondence　of　its　teeth　with　the

glossopetrae；　left　no　rational　doubt　as　to　the　origin　of　the

latter。　Thus　far；　the　work　of　Steno　went　little　further　than

that　of　Colonna；　but　it　fortunately　occurred　to　him　to　think　out

the　whole　subject　of　the　interpretation　of　fossils；　and　the

result　of　his　meditations　was　the　publication；　in　1669；　of　a

little　treatise　with　the　very　quaint　title　of　〃De　Solido　intra

Solidum　naturaliter　contento。〃　The　general　course　of　Steno's

argument　may　be　stated　in　a　few　words。　Fossils　are　solid　bodies

which；　by　some　natural　process；　have　come　to　be　contained　within

other　solid　bodies；　namely；　the　rocks　in　which　they　are

embedded；　and　the　fundamental　problem　of　palaeontology；　stated

generally；　is　this：　〃Given　a　body　endowed　with　a　certain　shape

and　produced　in　accordance　with　natural　laws；　to　find　in　that

body　itself　the　evidence　of　the　place　and　manner　of　its

production。〃　The　only　way　of　solving　this　problem　is　by　the

application　of　the　axiom　that　〃like　effects　imply　like　causes；〃

or　as　Steno　puts　it；　in　reference　to　this　particular　case；　that

〃bodies　which　are　altogether　similar　have　been　produced　in　the

same　way。〃　Hence；　since　the　glossopetrae　are　altogether

similar　to　sharks'　teeth；　they　must　have　been　produced　by

sharklike　fishes；　and　since　many　fossil　shells　correspond；　down

to　the　minutest　details　of　structure；　with　the　shells　of

existing　marine　or　freshwater　animals；　they　must　have　been

produced　by　similar　animals；　and　the　like　reasoning　is　applied

by　Steno　to　the　fossil　bones　of　vertebrated　animals；　whether

aquatic　or　terrestrial。　To　the　obvious　objection　that　many

fossils　are　not　altogether　similar　to　their　living　analogues；

differing　in　substance　while　agreeing　in　form；　or　being　mere

hollows　or　impressions；　the　surfaces　of　which　are　figured　in　the

same　way　as　those　of　animal　or　vegetable　organisms；　Steno

replies　by　pointing　out　the　changes　which　take　place　in　organic

remains　embedded　in　the　earth；　and　how　their　solid　substance　may

be　dissolved　away　entirely；　or　replaced　by　mineral　matter；　until

nothing　is　left　of　the　original　but　a　cast；　an　impression；　or　a

mere　trace　of　its　contours。　The　principles　of　investigation　thus

excellently　stated　and　illustrated　by　Steno　in　1669；　are　those

which　have；　consciously　or　unconsciously；　guided　the　researches

of　palaeontologists　ever　since。　Even　that　feat　of　palaeontology

which　has　so　powerfully　impressed　the　popular　imagination；　t