autobiography and selected essays-第24部分

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processes；　it　may　be　resolved　into　carbonic　acid　and　quicklime。　　If

you　pass　the　same　carbonic　acid　over　the　very　quicklime　thus

obtained；　you　will　obtain　carbonate　of　lime　again；　but　it　will　not

be　calc…spar；　nor　anything　like　it。　　Can　it；　therefore；　be　said

that　chemical　analysis　teaches　nothing　about　the　chemical

composition　of　calc…spar？　　Such　a　statement　would　be　absurd；　but　it

is　hardly　more　so　than　the　talk　one　occasionally　hears　about　the

uselessness　of　applying　the　results　of　chemical　analysis　to　the

living　bodies　which　have　yielded　them。



One　fact；　at　any　rate；　is　out　of　reach　of　such　refinements；　and

this　is；　that　all　the　forms　of　protoplasm　which　have　yet　been

examined　contain　the　four　elements；　carbon；　hydrogen；　oxygen；　and

nitrogen；　in　very　complex　union；　and　that　they　behave　similarly

towards　several　reagents。　　To　this　complex　combination；　the　nature

of　which　has　never　been　determined　with　exactness；　the　name　of

Protein　has　been　applied。　　And　if　we　use　this　term　with　such

caution　as　may　properly　arise　out　of　our　comparative　ignorance　of

the　things　for　which　it　stands；　it　may　be　truly　said；　that　all

protoplasm　is　proteinaceous；　or；　as　the　white；　or　albumen；　of　an

egg　is　one　of　the　commonest　examples　of　a　nearly　pure　proteine

matter；　we　may　say　that　all　living　matter　is　more　or　less

albuminoid。



Perhaps　it　would　not　yet　be　safe　to　say　that　all　forms　of

protoplasm　are　affected　by　the　direct　action　of　electric　shocks；

and　yet　the　number　of　cases　in　which　the　contraction　of　protoplasm

is　shown　to　be　affected　by　this　agency　increases　every　day。



Nor　can　it　be　affirmed　with　perfect　confidence；　that　all　forms　of

protoplasm　are　liable　to　undergo　that　peculiar　coagulation　at　a

temperature　of　40…50　degrees　centigrade；　which　has　been　called

〃heat…stiffening；〃　though　Kuhne's　＇101＇　beautiful　researches　have

proved　this　occurrence　to　take　place　in　so　many　and　such　diverse

living　beings；　that　it　is　hardly　rash　to　expect　that　the　law　holds

good　for　all。





Enough　has；　perhaps；　been　said　to　prove　the　existence　of　a　general

uniformity　in　the　character　of　the　protoplasm；　or　physical　basis；

of　life；　in　whatever　group　of　living　beings　it　may　be　studied。　　But

it　will　be　understood　that　this　general　uniformity　by　no　means

excludes　any　amount　of　special　modifications　of　the　fundamental

substance。　　The　mineral；　carbonate　of　lime；　assumes　an　immense

diversity　of　characters；　though　no　one　doubts　that；　under　all　these

Protean　changes；　it　is　one　and　the　same　thing。



And　now；　what　is　the　ultimate　fate；　and　what　the　origin；　of　the

matter　of　life？



Is　it；　as　some　of　the　older　naturalists　supposed；　diffused

throughout　the　universe　in　molecules；　which　are　indestructible　and

unchangeable　in　themselves；　but；　in　endless　transmigration；　unite

in　innumerable　permutations；　into　the　diversified　forms　of　life　we

know？　　Or；　is　the　matter　of　life　composed　of　ordinary　matter；

differing　from　it　only　in　the　manner　in　which　its　atoms　are

aggregated？　　Is　it　built　up　of　ordinary　matter；　and　again　resolved

into　ordinary　matter　when　its　work　is　done？



Modern　science　does　not　hesitate　a　moment　between　these

alternatives。　　Physiology　writes　over　the　portals　of　life



〃Debemur　morti　nos　nostraque；〃＇102＇



with　a　profounder　meaning　than　the　Roman　poet　attached　to　that

melancholy　line。　　Under　whatever　disguise　it　takes　refuge；　whether

fungus　or　oak；　worm　or　man；　the　living　protoplasm　not　only

ultimately　dies　and　is　resolved　into　its　mineral　and　lifeless

constituents；　but　is　always　dying；　and；　strange　as　the　paradox　may

sound；　could　not　live　unless　it　died。



In　the　wonderful　story　of　the　Peau　de　Chagrin；＇103＇　the　hero　becomes

possessed　of　a　magical　wild　ass'　skin；　which　yields　him　the　means

of　gratifying　all　his　wishes。　　But　its　surface　represents　the

duration　of　the　proprietor's　life；　and　for　every　satisfied　desire

the　skin　shrinks　in　proportion　to　the　intensity　of　fruition；　until

at　length　life　and　the　last　handbreadth　of　the　peau　de　chagrin；

disappear　with　the　gratification　of　a　last　wish。



Balzac's　＇104＇　studies　had　led　him　over　a　wide　range　of　thought　and

speculation；　and　his　shadowing　forth　of　physiological　truth　in　this

strange　story　may　have　been　intentional。　　At　any　rate；　the　matter

of　life　is　a　veritable　peau　de　chagrin；　and　for　every　vital　act　it

is　somewhat　the　smaller。　　All　work　implies　waste；　and　the　work　of

life　results；　directly　or　indirectly；　in　the　waste　of　protoplasm。



Every　word　uttered　by　a　speaker　costs　him　some　physical　loss；　and；

in　the　strictest　sense；　he　burns　that　others　may　have　lightso

much　eloquence；　so　much　of　his　body　resolved　into　carbonic　acid；

water；　and　urea。　　It　is　clear　that　this　process　of　expenditure

cannot　go　on　for　ever。　　But；　happily；　the　protoplasmic　peau　de

chagrin　differs　from　Balzac's　in　its　capacity　of　being　repaired；

and　brought　back　to　its　full　size；　after　every　exertion。



For　example；　this　present　lecture；　whatever　its　intellectual　worth

to　you；　has　a　certain　physical　value　to　me；　which　is；　conceivably；

expressible　by　the　number　of　grains　of　protoplasm　and　other　bodily

substance　wasted　in　maintaining　my　vital　processes　during　its

delivery。　　My　peau　de　chagrin　will　be　distinctly　smaller　at　the　end

of　the　discourse　than　it　was　at　the　beginning。　　By　and　by；　I　shall

probably　have　recourse　to　the　substance　commonly　called　mutton；　for

the　purpose　of　stretching　it　back　to　its　original　size。　　Now　this

mutton　was　once　the　living　protoplasm；　more　or　less　modified；　of

another　animala　sheep。　　As　I　shall　eat　it；　it　is　the　same　matter

altered；　not　only　by　death；　but　by　exposure　to　sundry　artificial

operations　in　the　process　of　cooking。



But　these　changes；　whatever　be　their　extent；　have　not　rendered　it

incompetent　to　resume　its　old　functions　as　matter　of　life。　　A

singular　inward　laboratory；　which　I　possess；　will　dissolve　a

certain　portion　of　the　modified　protoplasm；　the　solution　so　formed

will　pass　into　my　veins；　and　the　subtle　influences　to　which　it　will

then　be　subjected　will　convert　the　dead　protoplasm　into　living

protoplasm；　and　transubstantiate　sheep　into　man。



Nor　is　this　all。　　If　digestion　were　a　thing　to　be　trifled　with；　I

might　sup　upon　lobster；　and　the　matter　of　life　of　the　crustacean

would　undergo　the　same　wonderful　metamorphosis　into　humanity。　　And

were　I　to　return　to　my　own　place　by　sea；　and　undergo　shipwreck；　the

crustacean　might；　and　probably　would；　return　the　compliment；　and

demonstrate　our　common　nature　by　turning　my　protoplasm　into　living

lobster。　　Or；　if　nothing　better　were　to　be　had；　I　might　supply　my

wants　with　mere　bread；　and　I　should　find　the　protoplasm　of　the

wheat…plant　to　be　convertible　into　man；　with　no　more　trouble　than

that　of　the　sheep；　and　with　far　less；　I　fancy；　than　that　of　the

lobster。



Hence　it　appears　to　be　a　matter　of　no　great　moment　what　animal；　or

what　plant；　I　lay　under　contribution　for　protoplasm；　and　the　fact

speaks　volumes　for　the　general　identity　of　that　substance　in　all

living　beings。　　I　share　this　catholicity　of　assimilation　with　other

animals；　all　of　which；　so　far　as　we　know；　could　thrive　equally　well

on　the　protoplasm　of　any　of　their　fellows；　or　of　any　plant；　but

here　the　assimilative　powers　of　the　animal　world　cease。　　A　solution

of　smelling…salts　in　water；　with　an　infinitesimal　proportion　of

some　other　saline　matters；　contains　all　the　elementary　bodies　which

enter　into　the　composition　of　protoplasm；　but；　as　I　need　hardly

say；　a　hogshead　of　that　fluid　would　not　keep　a　hungry　man　from

starving；　nor　would　it　save　any　animal　whatever　from　a　like　fate。

An　animal　cannot　make　protoplasm；　but　must　take　it　ready…made　from

some　other　animal；　or　some　plantthe　animal's　highest　feat　of

constructive　chemistry　being　to　convert　dead　protoplasm　into　that

living　matter　of　life　which　is　appropriate　to　itself。



Therefore；　in　seeking　for　the　origin　of　protoplasm；　we　must

eventually　turn　to　the　vegetable　world。　　A　fluid　containing

carbonic　acid；　water；　and　nitrogenous　salts；　which　offers　such　a

Barmecide　feast　＇105＇　to　the　animal；　is　a　table　richly　spread　to

multitudes　of　plants；　and；　with　a　due　supply　of　only　such

materials；　many　a　plant　will　not　only　maintain　itself　in　vigour；

but　grow　and　multiply　until　it　has　increased　a　million…fold；　or　a

million　million…fold；　the　quantity　of　protoplasm　which　it

originally　possessed；　in　this　way　building　up　the　matter　of　life；

to　an　indefinite　extent；　from　the　common　matter　of　the　universe。



Thus；　the　animal　can　only　raise　the　complex　substance　of　dead

protoplasm　to　the　higher　power；　as　one　may　say；　of　living

protoplasm；　while　the　plant　can　raise　the　less　complex　substances

carbonic　acid；　water；　and　nitrogenous　saltsto　the　same　stage　of

living　protoplasm；　if　not　to　the　same　level。　　But　the　plant　also

has　its　limitations。　　Some　of　the　fungi；　for　example；　appear　to

need　higher　compounds　to　start　with；　and　no　known　plant　can　live

upon　the　uncompounded　elements　of　protoplasm。　　A　plant　supplied

with　pure　carbon；　hydrogen；　oxygen；　and　nitrogen；　phosphorus；

sulphur；　and　the　like；　would　as　infallibly　die　as　the　animal　in　his

bath　of　smelling…salts；　though　it　would　be　surrounded　by　all　the

constituents　of　protoplasm。　　Nor；　indeed；　need　the　process　of

simplification　of　vegetable　food　be　carried　so　far　as　this；　in

order　to　arrive　at　the　limit　of　the　plant's　thaumaturgy。　　Let

water；　carbonic　acid；　and　all　the　other　needful　constituents　be

supplied　except　nitrogenous　salts；　and　an　ordinary　plant　will　still

be　unable　to　manufacture　protoplasm。



Thus　the　matter　of　life；　so　far　as　we　know　it　（and　we　have　no　right

to　speculate　on　any　other）；　breaks　up；　in　consequence　of　that

continual　death　which　is　the　condition　of　its　manifesting　vitality；

into　carbonic　acid；　water；　and　nitrogenous　compounds；　which

certainly　possess　no　properties　but　those　of　ordinary　matter。　　And

out　of　these