《A Short History of Nearly Everything》第124章

d—but　mostly　they　die　because　they　are　told　to。
indeed；　if　not　told　to　live—if　not　given　some　kind　of　active　instruction　from　another　cell—cells　automatically　kill　themselves。　cells　need　a　lot　of　reassurance。
when；　as　occasionally　happens；　a　cell　fails　to　expire　in　the　prescribed　manner；　but　ratherbegins　to　divide　and　proliferate　wildly；　we　call　the　result　cancer。　cancer　cells　are　really　justconfused　cells。　cells　make　this　mistake　fairly　regularly；　but　the　body　has　elaboratemechanisms　for　dealing　with　it。　it　is　only　very　rarely　that　the　process　spirals　out　of　control。　onaverage；　humans　suffer　one　fatal　malignancy　for　each　100　million　billion　cell　divisions。
cancer　is　bad　luck　in　every　possible　sense　of　the　term。
the　wonder　of　cells　is　not　that　things　occasionally　go　wrong；　but　that　they　manageeverything　so　smoothly　for　decades　at　a　stretch。　they　do　so　by　constantly　sending　andmonitoring　streams　of　messages—a　cacophony　of　messages—from　all　around　the　body：
instructions；　queries；　corrections；　requests　for　assistance；　updates；　notices　to　divide　or　expire。
most　of　these　signals　arrive　by　means　of　couriers　called　hormones；　chemical　entities　such　asinsulin；　adrenaline；　estrogen；　and　testosterone　that　convey　information　from　remote　outpostslike　the　thyroid　and　endocrine　glands。　still　other　messages　arrive　by　telegraph　from　the　brainor　from　regional　centers　in　a　process　called　paracrine　signaling。　finally；　cells　municatedirectly　with　their　neighbors　to　make　sure　their　actions　are　coordinated。
what　is　perhaps　most　remarkable　is　that　it　is　all　just　random　frantic　action；　a　sequence　ofendless　encounters　directed　by　nothing　more　than　elemental　rules　of　attraction　and　repulsion。
there　is　clearly　no　thinking　presence　behind　any　of　the　actions　of　the　cells。　it　all　just　happens；smoothly　and　repeatedly　and　so　reliably　that　seldom　are　we　even　conscious　of　it；　yet　somehowall　this　produces　not　just　order　within　the　cell　but　a　perfect　harmony　right　across　the　organism。
in　ways　that　we　have　barely　begun　to　understand；　trillions　upon　trillions　of　reflexive　chemicalreactions　add　up　to　a　mobile；　thinking；　decision…making　you—or；　e　to　that；　a　rather　lessreflective　but　still　incredibly　organized　dung　beetle。　every　living　thing；　never　forget；　is　awonder　of　atomic　engineering。
indeed；　some　organisms　that　we　think　of　as　primitive　enjoy　a　level　of　cellular　organizationthat　makes　our　own　look　carelessly　pedestrian。　disassemble　the　cells　of　a　sponge　（by　passingthem　through　a　sieve；　for　instance）；　then　dump　them　into　a　solution；　and　they　will　find　theirway　back　together　and　build　themselves　into　a　sponge　again。　you　can　do　this　to　them　overand　over；　and　they　will　doggedly　reassemble　because；　like　you　and　me　and　every　other　livingthing；　they　have　one　overwhelming　impulse：　to　continue　to　be。
and　that’s　because　of　a　curious；　determined；　barely　understood　molecule　that　is　itself　notalive　and　for　the　most　part　doesn’t　do　anything　at　all。　we　call　it　dna；　and　to　begin　tounderstand　its　supreme　importance　to　science　and　to　us　we　need　to　go　back　160　years　or　so　tovictorian　england　and　to　the　moment　when　the　naturalist　charles　darwin　had　what　has　beencalled　“the　single　best　idea　that　anyone　has　ever　had”—and　then；　for　reasons　that　take　a　littleexplaining；　locked　it　away　in　a　drawer　for　the　next　fifteen　years。
x
25DARWIN’S　SINGULAR　NOTION
小x说s网
in　the　late　summer　or　early　autumn　of　1859；　whitwell　elwin；　editor　of　the　respectedbritish　journal　the　quarterly　review；　was　sent　an　advance　copy　of　a　new　book　by　thenaturalist　charles　darwin。　elwin　read　the　book　with　interest　and　agreed　that　it　had　merit；　butfeared　that　the　subject　matter　was　too　narrow　to　attract　a　wide　audience。　he　urged　darwin　towrite　a　book　about　pigeons　instead。　“everyone　is　interested　in　pigeons；”　he　observedhelpfully。
elwin’s　sage　advice　was　ignored；　and　on　the　origin　of　species　by　means　of　naturalselection；　or　the　preservation　of　favoured　races　in　the　struggle　for　life　was　published　in　latenovember　1859；　priced　at　fifteen　shillings。　the　first　edition　of　1；250　copies　sold　out　on　thefirst　day。　it　has　never　been　out　of　print；　and　scarcely　out　of　controversy；　in　all　the　time　since—not　bad　going　for　a　man　whose　principal　other　interest　was　earthworms　and　who；　but　for　asingle　impetuous　decision　to　sail　around　the　world；　would　very　probably　have　passed　his　lifeas　an　anonymous　country　parson　known　for；　well；　for　an　interest　in　earthworms。
charles　robert　darwin　was　born　on　february　12；　1809；1in　shrewsbury；　a　sedate　markettown　in　the　west　midlands　of　england。　his　father　was　a　prosperous　and　well…regardedphysician。　his　mother；　who　died　when　charles　was　only　eight；　was　the　daughter　of　josiahwedgwood；　of　pottery　fame。
darwin　enjoyed　every　advantage　of　upbringing；　but　continually　pained　his　widowed　fatherwith　his　lackluster　academic　performance。　“you　care　for　nothing　but　shooting；　dogs；　and　rat…catching；　and　you　will　be　a　disgrace　to　yourself　and　all　your　family；”　his　father　wrote　in　a　linethat　nearly　always　appears　just　about　here　in　any　review　of　darwin’s　early　life。　although　hisinclination　was　to　natural　history；　for　his　father’s　sake　he　tried　to　study　medicine　at　edinburghuniversity　but　couldn’t　bear　the　blood　and　suffering。　the　experience　of　witnessing　anoperation　on　an　understandably　distressed　child—this　was　in　the　days　before　anesthetics；　ofcourse—left　him　permanently　traumatized。　he　tried　law　instead；　but　found　that　insupportablydull　and　finally　managed；　more　or　less　by　default；　to　acquire　a　degree　in　divinity　fromcambridge。
a　life　in　a　rural　vicarage　seemed　to　await　him　when　from　out　of　the　blue　there　came　a　moretempting　offer。　darwin　was　invited　to　sail　on　the　naval　survey　ship　hms　beagle；　essentiallyas　dinner　pany　for　the　captain；　robert　fitzroy；　whose　rank　precluded　his　socializing　withanyone　other　than　a　gentleman。　fitzroy；　who　was　very　odd；　chose　darwin　in　part　because　heliked　the　shape　of　darwin’s　nose。　（it　betokened　depth　of　character；　he　believed。）　darwin　wasnot　fitzroy’s　first　choice；　but　got　the　nod　when　fitzroy’s　preferred　panion　dropped　out。
from　a　twenty…first…century　perspective　the　two　men’s　most　striking