An Account of the Sensitive Quality of the Tree Averrhoa Carambola. In a Letter from Robert Bruce, M.D. to Sir Joseph Banks, Bart. P.R.S

An Account of the Sensitive Quality of the Tree Averrhoa Carambola. In a Letter fromRobert Bruce, M.D. to Sir Joseph Banks, Bart. P.R.S.Author(s): Robert BruceSource: Philosophical Transactions of the Royal Society of London, Vol. 75 (1785), pp. 356-360Published by: The Royal SocietyStable URL: http://www.jstor.org/stable/106763 .

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W20*,ffn Xccaunt < t1:a .4X@Xtetd/;tW af tte S%ree tvetr1Aoa

Read April T 49 I;785.

HE -etrkot*;C-tb6XX;Xi-v>v9+ *f>-teX called ;a Benga1 the Camruc or Canirunga, is polEeINed of a power

ethat*f1milar to A ftediEs idft Mifiat wthtch are term-ed

if itwe plants ; its lcaves; oll beit E touchedX K moye- tery R perw

sepiti-My. !-}X}ilzeMimofa tlle rntving fatultyex*iJtbthenlAndes}

ti2, Wthehadtlefs-oftth-e woi*7 thostaCt-5eexpeaed-in tlle Carartunga. Thq learves gre alterllate< pinnatedt witll an

tdd $ollet, and iiR 6Ur COmmOll pfi-6OIl iIl .the iday-timR.

-am lwFzon-tal, or >om the fame- plaile wii thc +h ^ *om which <theyv come .out. 1 beitzg tollled>>--t4-8- move- t.ms filvetdownwasd-sX freqently ia fo P gre;¢-Sbt>:dQreti£ tht two opRoie almoit touch osle anoether by the;W tifflidews} t t young oMlles folaQtimes esthr ce itlto so:at^j-er;ave¢;p ^each othet;

The ole o-if the leavesfof one pinna move byWllrrlking the l!Dranch with the tlail of the t;nger, or other hard fubRance; er each leaf call le mHoved fingly by making an lmpreS1on that ffiall -tzo-t extelld beyd ;thattltWf + In this uray the leaves Qf

eue fi;de;of the pintat may be Pi&gto move, one after ano$therg hiiR tbe oppollte contitlue as they were X or you may make

them

tt ;354 :]



Dro} BRVC£$ £ fe a s

*Xm- mqYe- *matly;l o?in fhortt m atly order ypu pIeaSe7 bJr t.Uc- il=w. t. properv F?,?nnier, ,th,6 l:ea- you, witi to put irl mo* .

tion.*-w 43#s+th¢V¢iwpreIliont al-tho made on a fingle leaf; be Ilrongt all the leaves on that pinna, and fometimes oF tht nSighbounn?:>fwill be affb&ed by: w.

Wh4-Syat r firIt -::fiCwd. furpnElng wass dsat notwithffHitlg> x s vi s . z S 4 ., Se . , e . . { 4 * . . . . i, . . ..

thei5-a£U@11t fillfibil4r of- the leaf;; r -could;with9fw pair oR iharp SciIErs mtaE Xlarge incifions infirvj wifhout oecafionit$ thet,J fmall-eIl moteiotl ;.- nLay7 even cut itE 3lmoR entirely og awd. the. relnainiL-$ .part.. .flrill rt continue . unm. ov.ed:; .. md -thaa.t tlz]s.fZ b. muchotlgitbS.-ulQ.1d.a£<.vw.it.h e i¢.g¢r;.or piBtrtOi f the- izIIirs* motiolz.< wou1d tak¢) plac.e M .d . inJ* had.^.beenS7: ohred. But. otll filrth.er examina.tions I founrd, that. al.thoughi the lea£ was . the . ofietaElble part . .which .mov.edw. it- was; ill i&t en.tirely pa.flzve, a.tud ffiat.th.e pet-oluswasth.efIbat.both of.fel1lE;-* asld.. aAion . r .>.aItou the 1eai mitit .be cut. in;..piec.es,. or-: eueezed w.ith g;r.eat force. provided. its.>ddifedwill. lras not chang;ed, witi}out any motion butrgocmfioneelX yer, if thei-m-< prelditonS otlM the IeC was Amade= ltk fiach. a- w-ay as: to;afe:;tI<c-< petiolusy tsheltloll took pl-ae. Whens thereforeI;-wanted to cotwfilze ffie motio: to 0 a flng;ie vlsf;^ fi eitherY tou;sEled it fo as . e + * t s @ J

olQy +> aid it9 0Wn l?eeious} or wlthouft meddlit}g wi.thJ ther. Ieai;.tuchexl the petiolus. \vL i;7 at1y fmallwpostlted bodygw as a;. piv or knife.

Bycompreilllg the utlverfilt petiolussnear ie placewhere a par.tiS .t COI nes out, the Ieaf moves ill a iw icondsX il} tlCx fmme malaile« as if yon Uad.btuchedXthe partial petiolus

. . . \ .

Wlle.tller the i.mprelEotl be made ly pundures Frwfiiota->+ or compreflonS the motion does;not..l-lllalltlyfbllow; generally-

iMucral .. fno1.XNds: itltewe.XleF alld. theil. it is ....................... rlot by ... a. jirkg Xbut-

ws;u1v



338 Dr. BR- 3caint of a

regular and gradual. xAfterwards, Wheta;the leates 0 ret-urn tb *heir former fituation, which is commonly \ itl a; quarter of: ̂

bur or lefs, it is in fQ nOw a -manner asS fto be almoR :0 imp - -5 ceptible.

OI1 fttlckizg a pin into the univerEal petiolus at its origing the leaf next it, which is alwaysf on the; outer fide, ffloves fitIl; Nthen the firR leaf on the oppofite flde, nextS ehe; fecond leaf on

the outer, arld fo on. But-this regu3;at progreffiloll feldom conX . . .

tinues throughou-t; for the leaves-oll the outer fide of the pinna feem to be affeAed both-- more quickly, a3ed wth>t rnore:energy, than thofe of the itlner fio thati the fourth Ieaf ollVthe outer fide frequelltly moves as bonX as the third on the illner; and fometlmes a leaf, efpecially oll the truner fide, does not move aKt all, whilA thofe above and l)elow it are affeEted in Xtheir pro

er time. Sometimes the leaves at the extremity of the petio- llis move fooner thaou feveral otilers whgich were nearer the place where the pin was put in.

On maliing a compreIElon nwith a: pair of pincers on the uni- rerfal petiolus, between any two pair of leaves, thofe above the compreffed part, or nearer the extremity of the petiolus,, f

move foorler than thofe ullder it, or nearer thet Vorigin-; and fre quently the motion will extetld upwards to the extreme leaCa whilIt below it perh-aps does not go farther thatl the neareR pair.

If the leaves happen to be blown w the wind againS Ot]t

another, or agairsR tile brallches,- they are frequentlty putin motion; but WhtI1 a branch is moved gently, either by the hand or the wind, without firikillg agaitlR; any thing, no fmotion of the leaves takes place.

When left to themSellres in th-e day-time,;{haded from the: f.un witld, rain, or atly diIturbing cauSeX the appearance of

7 the



f+X >,rjzy qf zie Averrhoa CaramEvola 359 ie leaves is diSereat fronz tluat of other pirlnated plalts. l;n the IaR a great unifbrmity fubfiRs ill theslefipeaiVC pQtion of

e leaves on the pinlla; IJUt llere forne will be Setl Qtl the horizolltal planea foLue raiSed above it, an-d others fillell uLlder it , and ill arl hour or SoS WitlloUt ally order or regtllarity7 svhict} I could ol)fersre, a11 theie will have chand tlleir refpedive pofitions. I Ilate feetl a leaf; which was high upX fill dowtl >

this it did as quickly as if a Ilrong impreilotl kad lzectl macle otl it, IJUt there was no caulE to be perceived.

Cuttillg the bark of the laran-ch dowIl t the woods alld even feparating it about the fpace of half atl ialch all rou1wdX fo as to

R4p all communicat1oli by the veils of - the bark does tlot fort the firS day afEt the leaves, either in their pofitioll or tMir

*

kptltUC e tor motlon. In a branch, which I cut tllrough-in fuch a manIzer as to

leave it fut?ended otlly by a little of the bark no thicker ttlall a read, the -leaves tlext day dtd not rife fo high as the others; but they were green and fFeth, and on being touched rnoved but in a much leIX degree than forlnerltn

After fUI1-i the leaws go to Reep, firS moving dowll b as to touch one another by their u-nder fides; tht rllewfbre per- brm rather more exterlfive motion at night of themfelves than they can be made to do itl the day-ttme by external impreiSiotls. With a convex lells I have colledced the rays of the IR1I1 011 a leaf; fo as to bllrn a hole in it, without OCCtfiOIlillg any motiolzo But when theexperiment is tried OI1 the petiolus the Inotic3tl is as quicl as if Som fitOtlg percuEon, aithough ttie rays wem not fo much cotlcentrated as to cauSe pain wllell applied ill the fame degree on the back of tTle hand; tlor had tEle tex-ture <35 the petiolus been any way& thanged by this, fbr next day it;

vOL IJXXV B b-b couSHl



3 Dr. BRTrCE>S Atveount,: &c. f

co-rlid 1lot lJe difiillguiffied5 tither by its appearance or movlzg power, from t-hofe oll which no- experiment had been madee

Tlle leaves tnove very faR from the eleEtrical Ihock, :everv altlwough a very gentle one; but the Rate of the atmofphere- mras fo uniXavoalralile br experiments of this kind, that l could

ot purfue them fo far as I -wilhed. 0

There are tsro other plantss tnentronsd as becies of this genUS bY LINESES. The firIlX the Averrhoa Dilimbi9 I-have IlOt had an opportutwity o-f Iceillg. The otKher, or Averrl-loa Acida does^ not feem tv beloE to the i:ime clafs; 1zor do it; leaves poICefs any o-f tlle moving properties of- the Carambola" LTNN]EUSE generic defc-ription of tlae Avelrhoae as of matly other plal;ts ill this co2alltry svhich heXhSd-lot an opportunity ot

feeilzg fie- is nott altogether accurate. The petals are con- neSced by the lower part: of t;he iatniLwav and ill thfis xvay they fall of vwhilR rlhe UIRS,UCS are quite di:itld. The fl;amina are mx five pairs>; p]aced ill t-Ile allgles o£-the germetl*- Of eacll -pair only one Itamen -s ferie, or iraffied with Ean arltheraA tRhe filameIlts are curved>+ - adapted to tbhe ffiape of the germen<O. prhey may be preSed dowvLl gently, ilz as to« remaill ; atld then>?

whell mo?ed a little upsvardsv rife with a fpring. The ifr*tbllx

are twice the letlgth;-o£ th.g-eVdeStitute;of alztllcrw.

talclltta} STov, 237 I 789



Documents

An Account of the Sensitive Quality of the Tree Averrhoa Carambola. In a Letter from Robert Bruce, M.D. to Sir Joseph Banks, Bart. P.R.S