articleon\"CharlesDarwin\"（’Nature’Series，1882）。）Thestateofknowledge，asregardstheCirripedes，wasmostunsatisfactoryatthetimethatmyfatherbegantoworkatthem。Asanillustrationofthisfact，itmaybementionedthathehadeventore—organisethenomenclatureofthegroup，or，asheexpressedit，he\"unwillinglyfounditindispensabletogivenamestoseveralvalves，andtosomefewofthesofterpartsofCirripedes。\"（Vol。i。page3。）Itisinterestingtolearnfromhisdiarytheamountoftimewhichhegavetodifferentgenera。ThusthegenusChthamalus，thedescriptionofwhichoccupiestwenty—twopages，occupiedhimforthirty—sixdays;Coronulatooknineteendays，andisdescribedintwenty—sevenpages。WritingtoFitz—Roy，hespeaksofbeing\"forthelasthalf—monthdailyhardatworkindissectingalittleanimalaboutthesizeofapin’shead，fromtheChonosarchipelago，andIcouldspendanothermonth，anddailyseemorebeautifulstructure。\"
Thoughhebecameexcessivelywearyoftheworkbeforetheendoftheeightyears，hehadmuchkeenenjoymentinthecourseofit。ThushewrotetoSirJ。D。Hooker（1847？）:——\"Asyousay，thereisanextraordinarypleasureinpureobservation;notbutwhatIsuspectthepleasureinthiscaseisratherderivedfromcomparisonsforminginone’smindwithalliedstructures。Afterhavingbeensolongemployedinwritingmyoldgeologicalobservations，itisdelightfultouseone’seyesandfingersagain。\"Itwas，infact，areturntotheworkwhichoccupiedsomuchofhistimewhenatseaduringhisvoyage。Hiszoologicalnotesofthatperiodgiveanimpressionofvigorouswork，hamperedbyignoranceandwantofappliances。Andhisuntiringindustryinthedissectionofmarineanimals，especiallyofCrustacea，musthavebeenofvaluetohimastrainingforhisCirripedework。Mostofhisworkwasdonewiththesimpledissectingmicroscope——butitwastheneedwhichhefoundforhigherpowersthatinducedhim，in1846，tobuyacompoundmicroscope。HewrotetoHooker:——\"WhenIwasdrawingwithL。，Iwassodelightedwiththeappearanceoftheobjects，especiallywiththeirperspective，asseenthroughtheweakpowersofagoodcompoundmicroscope，thatIamgoingtoorderone;indeed，Ioftenhavestructuresinwhichthe1/30isnotpowerenough。\"
Duringpartofthetimecoveredbythepresentchapter，myfathersufferedperhapsmorefromill—healththanatanyothertimeofhislife。Hefeltseverelythedepressinginfluenceoftheselongyearsofillness;thusasearlyas1840hewrotetoFox:\"Iamgrownadull，old，spiritlessdogtowhatIusedtobe。OnegetsstupiderasonegrowsolderIthink。\"Itisnotwonderfulthatheshouldsohavewritten，itisrathertobewonderedatthathisspiritwithstoodsogreatandconstantastrain。HewrotetoSirJ。D。Hookerin1845:\"Youareverykindinyourenquiriesaboutmyhealth;Ihavenothingtosayaboutit，beingalwaysmuchthesame，somedaysbetterandsomeworse。IbelieveIhavenothadonewholeday，orrathernight，withoutmystomachhavingbeengreatlydisordered，duringthelastthreeyears，andmostdaysgreatprostrationofstrength:thankyouforyourkindness;manyofmyfriends，Ibelieve，thinkmeahypochondriac。\"
Again，in1849，henotesinhisdiary:——\"January1sttoMarch10th。——Healthverybad，withmuchsicknessandfailureofpower。Workedonallwelldays。\"ThiswaswrittenjustbeforehisfirstvisittoDr。Gully’sWater—
CureEstablishmentatMalvern。InAprilofthesameyearhewrote:——\"I