Destructionsuperveneswhenthedeterminedgetsthebetterofthedeterminingbythehelpoftheenvironment（thoughinaspecialsensethewordputrefactionisappliedtopartialdestruction，whenathing’snatureisperverted）。Henceeverything，exceptfire，isliabletoputrefy;forearth，water，andairputrefy，beingallofthemmatterrelativelytofire。Thedefinitionofputrefactionis：thedestructionofthepeculiarandnaturalheatinanymoistsubjectbyexternalheat，thatis，bytheheatoftheenvironment。Sosincelackofheatisthegroundofthisaffectionandeverythinginasfarasitlacksheatiscold，bothheatandcoldwillbethecausesofputrefaction，whichwillbedueindifferentlytocoldintheputrefyingsubjectortoheatintheenvironment。
Thisexplainswhyeverythingthatputrefiesgrowsdrierandendsbybecomingearthordung。Thesubject’sownheatdepartsandcausesthenaturalmoisturetoevaporatewithit，andthenthereisnothinglefttodrawinmoisture，foritisathing’speculiarheatthatattractsmoistureanddrawsitin。Again，putrefactiontakesplacelessincoldthatinhotseasons，forinwinterthesurroundingairandwatercontainbutlittleheatandithasnopower，butinsummerthereismore。Again，whatisfrozendoesnotputrefy，foritscoldisgreaterthattheheatoftheairandsoisnotmastered，whereaswhataffectsathingdoesmasterit。Nordoesthatwhichisboilingorhotputrefy，fortheheatintheairbeinglessthanthatintheobjectdoesnotprevailoveritorsetupanychange。Sotooanythingthatisflowingorinmotionislessapttoputrefythanathingatrest，forthemotionsetupbytheheatintheairisweakerthanthatpre-existingintheobject，andsoitcausesnochange。Forthesamereasonagreatquantityofathingputrefieslessreadilythanalittle，forthegreaterquantitycontainstoomuchproperfireandcoldforthecorrespondingqualitiesintheenvironmenttogetthebetterof。Hence，theseaputrefiesquicklywhenbrokenupintoparts，butnotasawhole;andallotherwaterslikewise。Animalstooaregeneratedinputrefyingbodies，becausetheheatthathasbeensecreted，beingnatural，organizestheparticlessecretedwithit。
Somuchforthenatureofbecomingandofdestruction。
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Wemustnowdescribethenextkindsofprocesseswhichthequalitiesalreadymentionedsetupinactuallyexistingnaturalobjectsasmatter。
Oftheseconcoctionisduetoheat;itsspeciesareripening，boiling，broiling。Inconcoctionisduetocoldanditsspeciesarerawness，imperfectboiling，imperfectbroiling。（Wemustrecognizethatthethingsarenotproperlydenotedbythesewords：thevariousclassesofsimilarobjectshavenonamesuniversallyapplicabletothem;consequentlywemustthinkofthespeciesenumeratedasbeingnotwhatthosewordsdenotebutsomethinglikeit。）Letussaywhateachofthemis。Concoctionisaprocessinwhichthenaturalandproperheatofanobjectperfectsthecorrespondingpassivequalities，whicharethepropermatterofanygivenobject。Forwhenconcoctionhastakenplacewesaythatathinghasbeenperfectedandhascometobeitself。Itistheproperheatofathingthatsetsupthisperfecting，thoughexternalinfluencesmaycontributeinsomedegreestoitsfulfilment。Baths，forinstance，andotherthingsofthekindcontributetothedigestionoffood，buttheprimarycauseistheproperheatofthebody。Insomecasesofconcoctiontheendoftheprocessisthenatureofthething-nature，thatis，inthesenseoftheformalcauseandessence。Inothercasesitleadstosomepresupposedstatewhichisattainedwhenthemoisturehasacquiredcertainpropertiesoracertainmagnitudeintheprocessofbeingbroiledorboiledorofputrefying，orhoweverelseitisbeingheated。Thisstateistheend，forwhenithasbeenreachedthethinghassomeuseandwesaythatconcoctionhastakenplace。Mustisaninstanceofthis，andthematterinboilswhenitbecomespurulent，andtearswhentheybecomerheum，andsowiththerest。
Concoctionensueswheneverthematter，themoisture，ismastered。Forthematteriswhatisdeterminedbytheheatconnaturaltotheobject，andaslongastheratiobetweenthemexistsinitathingmaintainsitsnature。Hencethingsliketheliquidandsolidexcretaandejectaingeneralaresignsofhealth，andconcoctionissaidtohavetakenplaceinthem，fortheyshowthattheproperheathasgotthebetteroftheindeterminatematter。
Thingsthatundergoaprocessofconcoctionnecessarilybecomethickerandhotter，fortheactionofheatistomakethingsmorecompact，thicker，anddrier。
Thisthenisthenatureofconcoction：butinconcoctionisanimperfectstateduetolackofproperheat，thatis，tocold。Thatofwhichtheimperfectstateis，isthecorrespondingpassivequalitieswhicharethenaturalmatterofanything。
Somuchforthedefinitionofconcoctionandinconcoction。
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Ripeningisasortofconcoction;forwecallitripeningwhenthereisaconcoctionofthenutrimentinfruit。Andsinceconcoctionisasortofperfecting，theprocessofripeningisperfectwhentheseedsinfruitareabletoreproducethefruitinwhichtheyarefound;forinallothercasesaswellthisiswhatwemeanby’perfect’。Thisiswhat’ripening’meanswhenthewordisappliedtofruit。However，manyotherthingsthathaveundergoneconcoctionaresaidtobe’ripe’，thegeneralcharacteroftheprocessbeingthesame，thoughthewordisappliedbyanextensionofmeaning。Thereasonforthisextensionis，asweexplainedbefore，thatthevariousmodesinwhichnaturalheatandcoldperfectthemattertheydeterminehavenotspecialnamesappropriatedtothem。Inthecaseofboilsandphlegm，andthelike，theprocessofripeningistheconcoctionofthemoistureinthembytheirnaturalheat，foronlythatwhichgetsthebetterofmattercandetermineit。Soeverythingthatripensiscondensedfromaspirituousintoawaterystate，andfromawateryintoanearthystate，andingeneralfrombeingrarebecomesdense。Inthisprocessthenatureofthethingthatisripeningincorporatessomeofthematterinitself，andsomeitrejects。Somuchforthedefinitionofripening。
Rawnessisitsoppositeandisthereforeanimperfectconcoctionofthenutrimentinthefruit，namely，oftheundeterminedmoisture。
Consequentlyarawthingiseitherspirituousorwateryorcontainsbothspiritandwater。Ripeningbeingakindofperfecting，rawnesswillbeanimperfectstate，andthisstateisduetoalackofnaturalheatanditsdisproportiontothemoisturethatisundergoingtheprocessofripening。（Nothingmoistripenswithouttheadmixtureofsomedrymatter：wateraloneofliquidsdoesnotthicken。）Thisdisproportionmaybedueeithertodefectofheatortoexcessofthemattertobedetermined：hencethejuiceofrawthingsisthin，coldratherthanhot，andunfitforfoodordrink。Rawness，likeripening，isusedtodenoteavarietyofstates。Thustheliquidandsolidexcretaandcatarrhsarecalledrawforthesamereason，forineverycasethewordisappliedtothingsbecausetheirheathasnotgotthemasteryinthemandcompactedthem。Ifwegofurther，brickiscalledrawandsoismilkandmanyotherthingstoowhentheyaresuchastoadmitofbeingchangedandcompactedbyheatbuthaveremainedunaffected。Hence，whilewespeakof’boiled’water，wecannotspeakofrawwater，sinceitdoesnotthicken。Wehavenowdefinedripeningandrawnessandassignedtheircauses。
Boilingis，ingeneral，aconcoctionbymoistheatoftheindeterminatemattercontainedinthemoistureofthethingboiled，andthewordisstrictlyapplicableonlytothingsboiledinthewayofcooking。Theindeterminatematter，aswesaid，willbeeitherspirituousorwatery。Thecauseoftheconcoctionisthefirecontainedinthemoisture;forwhatiscookedinafrying-panisbroiled：itistheheatoutsidethataffectsitand，asforthemoistureinwhichitiscontained，itdriesthisupanddrawsitintoitself。Butathingthatisbeingboiledbehavesintheoppositeway：themoisturecontainedinitisdrawnoutofitbytheheatintheliquidoutside。Henceboiledmeatsaredrierthanbroiled;
for，inboiling，thingsdonotdrawthemoistureintothemselves，sincetheexternalheatgetsthebetteroftheinternal：iftheinternalheathadgotthebetteritwouldhavedrawnthemoisturetoitself。Noteverybodyadmitsoftheprocessofboiling：ifthereisnomoistureinit，itdoesnot（forinstance，stones），nordoesitifthereismoistureinitbutthedensityofthebodyistoogreatforit-to-bemastered，asinthecaseofwood。Butonlythosebodiescanbeboiledthatcontainmoisturewhichcanbeactedonbytheheatcontainedintheliquidoutside。Itistruethatgoldandwoodandmanyotherthingsaresaidtobe’boiled’：butthisisastretchofthemeaningoftheword，thoughthekindofthingintendedisthesame，thereasonfortheusagebeingthatthevariouscaseshavenonamesappropriatedtothem。Liquidstoo，likemilkandmust，aresaidtoundergoaprocessof’boiling’whentheexternalfirethatsurroundsandheatsthemchangesthesavourintheliquidintoagivenform，theprocessbeingthusinawaylikewhatwehavecalledboiling。
Theendofthethingsthatundergoboiling，orindeedanyformofconcoction，isnotalwaysthesame：somearemeanttobeeaten，somedrunk，andsomeareintendedforotheruses;forinstancedyes，too，aresaidtobe’boiled’。
Allthosethingsthenadmitof’boiling’whichcangrowdenser，smaller，orheavier;alsothosewhichdothatwithapartofthemselvesandwithapartdotheopposite，dividinginsuchawaythatoneportionthickenswhiletheothergrowsthinner，likemilkwhenitdividesintowheyandcurd。Oilbyitselfisaffectedinnoneoftheseways，andthereforecannotbesaidtoadmitof’boiling’。Suchthenisthepfciesofconcoctionknownas’boiling’，andtheprocessisthesameinanartificialandinanaturalinstrument，forthecausewillbethesameineverycase。
Imperfectboilingistheformofinconcoctionopposedtoboiling。
Nowtheoppositeofboilingproperlysocalledisaninconcoctionoftheundeterminedmatterinabodyduetolackofheatinthesurroundingliquid。（Lackofheatimplies，aswehavepointedout，thepresenceofcold。）Themotionwhichcausesimperfectboilingisdifferentfromthatwhichcausesboiling，fortheheatwhichoperatestheconcoctionisdrivenout。Thelackofheatisdueeithertotheamountofcoldintheliquidortothequantityofmoistureintheobjectundergoingtheprocessofboiling。Whereeitheroftheseconditionsisrealizedtheheatinthesurroundingliquidistoogreattohavenoeffectatall，buttoosmalltocarryouttheprocessofconcoctinguniformlyandthoroughly。Hencethingsareharderwhentheyareimperfectlyboiledthanwhentheyareboiled，andthemoistureinthemmoredistinctfromthesolidparts。Somuchforthedefinitionandcausesofboilingandimperfectboiling。
Broilingisconcoctionbydryforeignheat。Henceifamanweretoboilathingbutthechangeandconcoctioninitweredue，nottotheheatoftheliquidbuttothatofthefire，thethingwillhavebeenbroiledandnotboiledwhentheprocesshasbeencarriedtocompletion：iftheprocesshasgonetoofarweusetheword’scorched’
todescribeit。Iftheprocessleavesthethingdrierattheendtheagenthasbeendryheat。Hencetheoutsideisdrierthantheinside，theoppositebeingtrueofthingsboiled。Wheretheprocessisartificial，broilingismoredifficultthanboiling，foritisdifficulttoheattheinsideandtheoutsideuniformly，sincethepartsnearertothefirearethefirsttogetdryandconsequentlygetmoreintenselydry。Inthiswaytheouterporescontractandthemoistureinthethingcannotbesecretedbutisshutinbytheclosingofthepores。Nowbroilingandboilingareartificialprocesses，butthesamegeneralkindofthing，aswesaid，isfoundinnaturetoo。
Theaffectionsproducedaresimilarthoughtheylackaname;forartimitatesnature。Forinstance，theconcoctionoffoodinthebodyislikeboiling，forittakesplaceinahotandmoistmediumandtheagentistheheatofthebody。So，too，certainformsofindigestionarelikeimperfectboiling。Anditisnottruethatanimalsaregeneratedintheconcoctionoffood，assomesay。Reallytheyaregeneratedintheexcretionwhichputrefiesinthelowerbelly，andtheyascendafterwards。Forconcoctiongoesonintheupperbellybuttheexcretionputrefiesinthelower：thereasonforthishasbeenexplainedelsewhere。
Wehaveseenthattheoppositeofboilingisimperfectboiling：
nowthereissomethingcorrespondinglyopposedtothespeciesofconcoctioncalledbroiling，butitismoredifficulttofindanameforit。Itwouldbethekindofthingthatwouldhappeniftherewereimperfectbroilinginsteadofbroilingproperthroughlackofheatduetodeficiencyintheexternalfireortothequantityofwaterinthethingundergoingtheprocess。Forthenweshouldgettoomuchheatfornoeffecttobeproduced，buttoolittleforconcoctiontotakeplace。
Wehavenowexplainedconcoctionandinconcoction，ripeningandrawness，boilingandbroiling，andtheiropposites。
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Wemustnowdescribetheformstakenbythepassivequalitiesthemoistandthedry。Theelementsofbodies，thatis，thepassiveones，arethemoistandthedry;thebodiesthemselvesarecompoundedofthemandwhicheverpredominatesdeterminesthenatureofthebody;thussomebodiespartakemoreofthedry，othersofthemoist。Alltheformstobedescribedwillexisteitheractually，orpotentiallyandintheiropposite：forinstance，thereisactualmeltingandontheotherhandthatwhichadmitsofbeingmelted。
Sincethemoistiseasilydeterminedandthedrydeterminedwithdifficulty，theirrelationtooneanotherislikethatofadishanditscondiments。Themoistiswhatmakesthedrydeterminable，andeachservesasasortofgluetotheother-asEmpedoclessaidinhispoemonNature，’glueingmealtogetherbymeansofwater。’Thusthedeterminedbodyinvolvesthemboth。Oftheelementsearthisespeciallyrepresentativeofthedry，waterofthemoist，andthereforealldeterminatebodiesinourworldinvolveearthandwater。
Everybodyshowsthequalityofthatelementwhichpredominatesinit。
Itisbecauseearthandwaterarethematerialelementsofallbodiesthatanimalsliveinthemaloneandnotinairorfire。
Ofthequalitiesofbodieshardnessandsoftnessarethosewhichmustprimarilybelongtoadeterminedthing，foranythingmadeupofthedryandthemoistisnecessarilyeitherhardorsoft。Hardisthatthesurfaceofwhichdoesnotyieldintoitself;softthatwhichdoesyieldbutnotbyinterchangeofplace：water，forinstance，isnotsoft，foritssurfacedoesnotyieldtopressureorsinkinbutthereisaninterchangeofplace。Thosethingsareabsolutelyhardandsoftwhichsatisfythedefinitionabsolutely，andthosethingsrelativelysowhichdosocomparedwithanotherthing。Nowrelativelytooneanotherhardandsoftareindefinable，becauseitisamatterofdegree，butsincealltheobjectsofsensearedeterminedbyreferencetothefacultyofsenseitisclearlytherelationtotouchwhichdeterminesthatwhichishardandsoftabsolutely，andtouchisthatwhichweuseasastandardormean。Sowecallthatwhichexceedsithardandthatwhichfallsshortofitsoft。
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Abodydeterminedbyitsownboundarymustbeeitherhardorsoft;
foriteitheryieldsordoesnot。
Itmustalsobeconcrete：oritcouldnotbesodetermined。Sosinceeverythingthatisdeterminedandsolidiseitherhardorsoftandthesequalitiesareduetoconcretion，allcompositeanddeterminedbodiesmustinvolveconcretion。Concretionthereforemustbediscussed。
Nowtherearetwocausesbesidesmatter，theagentandthequalitybroughtabout，theagentbeingtheefficientcause，thequalitytheformalcause。Henceconcretionanddisaggregation，dryingandmoistening，musthavethesetwocauses。
Butsinceconcretionisaformofdryingletusspeakofthelatterfirst。
Aswehaveexplained，theagentoperatesbymeansoftwoqualitiesandthepatientisactedoninvirtueoftwoqualities：actiontakesplacebymeansofheatorcold，andthequalityisproducedeitherbythepresenceorbytheabsenceofheatorcold;butthatwhichisacteduponismoistordryoracompoundofboth。Wateristheelementcharacterizedbythemoist，earththatcharacterizedbythedry，fortheseamongtheelementsthatadmitthequalitiesmoistanddryarepassive。Thereforecold，too，beingfoundinwaterandearth（bothofwhichwerecognizetobecold），mustbereckonedratherasapassivequality。Itisactiveonlyascontributingtodestructionorincidentallyinthemannerdescribedbefore;forcoldissometimesactuallysaidtoburnandtowarm，butnotinthesamewayasheatdoes，butbycollectingandconcentratingheat。
Thesubjectsofdryingarewaterandthevariouswateryfluidsandthosebodieswhichcontainwatereitherforeignorconnatural。ByforeignImeanlikethewaterinwool，byconnatural，likethatinmilk。Thewateryfluidsarewine，urine，whey，andingeneralthosefluidswhichhavenosedimentoronlyalittle，exceptwherethisabsenceofsedimentisduetoviscosity。Forinsomecases，inoilandpitchforinstance，itistheviscositywhichpreventsanysedimentfromappearing。
Itisalwaysaprocessofheatingorcoolingthatdriesthings，buttheagentinbothcasesisheat，eitherinternalorexternal。
Forevenwhenthingsaredriedbycooling，likeagarment，wherethemoistureexistsseparatelyitistheinternalheatthatdriesthem。Itcarriesoffthemoistureintheshapeofvapour（ifthereisnottoomuchofit），beingitselfdrivenoutbythesurroundingcold。Soeverythingisdried，aswehavesaid，byaprocesseitherofheatingorcooling，buttheagentisalwaysheat，eitherinternalorexternal，carryingoffthemoistureinvapour。ByexternalheatImeanaswherethingsareboiled：byinternalwheretheheatbreathesoutandtakesawayandusesupitsmoisture。Somuchfordrying。
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Liquefactionis，first，condensationintowater;second，themeltingofasolidifiedbody。Thefirst，condensation，isduetothecoolingofvapour：whatmeltingiswillappearfromtheaccountofsolidification。
Whateversolidifiesiseitherwateroramixtureofearthandwater，andtheagentiseitherdryheatorcold。Hencethoseofthebodiessolidifiedbyheatorcoldwhicharesolubleatallaredissolvedbytheiropposites。Bodiessolidifiedbythedry-hotaredissolvedbywater，whichisthemoist-cold，whilebodiessolidifiedbycoldaredissolvedbyfire，whichishot。Somethingsseemtobesolidifiedbywater，e。g。boiledhoney，butreallyitisnotthewaterbutthecoldinthewaterwhicheffectsthesolidification。Aqueousbodiesarenotsolidifiedbyfire：foritisfirethatdissolvesthem，andthesamecauseinthesamerelationcannothaveoppositeeffectsuponthesamething。Again，watersolidifiesowingtothedepartureofheat;soitwillclearlybedissolvedbytheentryintoitofheat：
cold，therefore，mustbetheagentinsolidifyingit。
Henceaqueousbodiesdonotthickenwhentheysolidify;forthickeningoccurswhenthemoisturegoesoffandthedrymattercomestogether，butwateristheonlyliquidthatdoesnotthicken。
Thosebodiesthataremadeupofbothearthandwateraresolidifiedbothbyfireandbycoldandineithercasearethickened。Theoperationofthetwoisinawaythesameandinawaydifferent。Heatactsbydrawingoffthemoisture，andasthemoisturegoesoffinvapourthedrymatterthickensandcollects。Coldactsbydrivingouttheheat，whichisaccompaniedbythemoistureasthisgoesoffinvapourwithit。Bodiesthataresoftbutnotliquiddonotthickenbutsolidifywhenthemoistureleavesthem，e。g。potter’sclayinprocessofbaking：butthosemixedbodiesthatareliquidthickenbesidessolidifying，likemilk。Thosebodieswhichhavefirstbeenthickenedorhardenedbycoldoftenbeginbybecomingmoist：thuspotter’sclayatfirstintheprocessofbakingsteamsandgrowssofter，andisliabletodistortionintheovensforthatreason。
Nowofthebodiessolidifiedbycoldwhicharemadeupbothofearthandwaterbutinwhichtheearthpreponderates，thosewhichsolidifybythedepartureofheatmeltbyheatwhenitentersintothemagain;thisisthecasewithfrozenmud。Butthosewhichsolidifybyrefrigeration，whereallthemoisturehasgoneoffinvapourwiththeheat，likeironandhorn，cannotbedissolvedexceptbyexcessiveheat，buttheycanbesoftened-thoughmanufacturedirondoesmelt，tothepointofbecomingfluidandthensolidifyingagain。
Thisishowsteelismade。Thedrosssinkstothebottomandispurgedaway：whenthishasbeendoneoftenandthemetalispurewehavesteel。Theprocessisnotrepeatedoftenbecausethepurificationofthemetalinvolvesgreatwasteandlossofweight。Buttheironthathaslessdrossisthebetteriron。Thestonepyrimachus，too，meltsandformsintodropsandbecomesfluid;afterhavingbeeninafluidstateitsolidifiesandbecomeshardagain。Millstones，too，meltandbecomefluid：whenthefluidmassbeginstosolidifyitisblackbutitsconsistencycomestobelikethatoflime。andearth，tooOfthebodieswhicharesolidifiedbydryheatsomeareinsoluble，othersaredissolvedbyliquid。Potteryandsomekindsofstonethatareformedoutofearthburntupbyfire，suchasmillstones，cannotbedissolved。Natronandsaltaresolublebyliquid，butnotallliquidbutonlysuchasiscold。Hencewaterandanyofitsvarietiesmeltthem，butoildoesnot。Fortheoppositeofthedry-hotisthecold-moistandwhattheonesolidifiedtheotherwilldissolve，andsooppositeswillhaveoppositeeffects。
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Ifabodycontainsmorewaterthanearthfireonlythickensit：ifitcontainsmoreearthfiresolidifiesit。Hencenatronandsaltandstoneandpotter’sclaymustcontainmoreearth。
Thenatureofoilpresentsthegreatestproblem。Ifwaterpreponderatedinit，coldoughttosolidifyit;ifearthpreponderated，thenfireoughttodoso。Actuallyneithersolidifies，butboththickenit。Thereasonisthatitisfullofair（henceitfloatsonthetopofwater，sinceairtendstorise）。
Coldthickensitbyturningtheairinitintowater，foranymixtureofoilandwateristhickerthaneither。Fireandthelapseoftimethickenandwhitenit。Thewhiteningfollowsontheevaporationofanywaterthatmayhavebeeninit;theisduetothechangeoftheairintowaterastheheatintheoilisdissipated。Theeffectinbothcasesisthesameandthecauseisthesame，butthemannerofitsoperationisdifferent。Bothheatandcoldthickenit，butneitherdriesit（neitherthesunnorcolddriesoil），notonlybecauseitisglutinousbutbecauseitcontainsair。Itsglutinousnaturepreventsitfromgivingoffvapourandsofiredoesnotdryitorboilitoff。
Thosebodieswhicharemadeupofearthandwatermaybeclassifiedaccordingtothepreponderanceofeither。Thereisakindofwine，forinstance，whichbothsolidifiesandthickensbyboiling-I
mean，must。AllbodiesofthiskindlosetheirwaterastheyThatitistheirwatermaybeseenfromthefactthatthevapourfromthemcondensesintowaterwhencollected。Sowhereversomesedimentisleftthisisofthenatureofearth。Someofthesebodies，aswehavesaid，arealsothickenedanddriedbycold。Forcoldnotonlysolidifiesbutalsodrieswater，andthickensthingsbyturningairintowater。
（Solidifying，aswehavesaid，isaformofdrying。）Nowthosethingsthatarenotthickenedbycold，butsolidified，belongrathertowater，e。g……wine，urine，vinegar，lye，whey。Butthosethingsthatarethickened（notbyevaporationduetofire）aremadeupeitherofearthorofwaterandair：honeyofearth，whileoilcontainsair。
Milkandblood，too，aremadeupofbothwaterandearth，thoughearthgenerallypredominatesinthem。So，too，aretheliquidsoutofwhichnatronandsaltareformed;andstonesarealsoformedfromsomemixturesofthiskind。Hence，ifthewheyhasnotbeenseparated，itburnsawayifyouboilitoverafire。Buttheearthyelementinmilkcanalsobecoagulatedbythehelpoffig-juice，ifyouboilitinacertainwayasdoctorsdowhentheytreatitwithfig-juice，andthisishowthewheyandthecheesearecommonlyseparated。
Whey，onceseparated，doesnotthicken，asthemilkdid，butboilsawaylikewater。Sometimes，however，thereislittleornocheeseinmilk，andsuchmilkisnotnutritiveandismorelikewater。Thecaseofbloodissimilar：colddriesandsosolidifiesit。Thosekindsofbloodthatdonotsolidify，likethatofthestag，belongrathertowaterandareverycold。Hencetheycontainnofibres：forthefibresareofearthandsolid，andbloodfromwhichtheyhavebeenremoveddoesnotsolidify。Thisisbecauseitcannotdry;forwhatremainsiswater，justaswhatremainsofmilkwhencheesehasbeenremovediswater。Thefactthatdiseasedbloodwillnotsolidifyisevidenceofthesamething，forsuchbloodisofthenatureofserumandthatisphlegmandwater，thenatureoftheanimalhavingfailedtogetthebetterofitanddigestit。
Someofthesebodiesaresoluble，e。g。natron，someinsoluble，e。g。pottery：ofthelatter，some，likehorn，canbesoftenedbyheat，others，likepotteryandstone，cannot。Thereasonisthatoppositecauseshaveoppositeeffects：consequently，ifsolidificationisduetotwocauses，thecoldandthedry，solutionmustbeduetothehotandthemoist，thatis，tofireandtowater（thesebeingopposites）：waterdissolvingwhatwassolidifiedbyfirealone，firewhatwassolidifiedbycoldalone。Consequently，ifanythingshappentobesolidifiedbytheactionofboth，theseareleastapttobesoluble。Suchacasewefindwherethingshavebeenheatedandarethensolidifiedbycold。Whentheheatinleavingthemhascausedmostofthemoisturetoevaporate，thecoldsocompactsthesebodiestogetheragainastoleavenoentranceevenformoisture。
Thereforeheatdoesnotdissolvethem（foritonlydissolvesthosebodiesthataresolidifiedbycoldalone），nordoeswater（foritdoesnotdissolvewhatcoldsolidifies，butonlywhatissolidifiedbydryheat）。Butironismeltedbyheatandsolidifiedbycold。Woodconsistsofearthandairandisthereforecombustiblebutcannotbemeltedorsoftenedbyheat。（Forthesamereasonitfloatsinwater-allexceptebony。Thisdoesnot，forotherkindsofwoodcontainapreponderanceofair，butinblackebonytheairhasescapedandsoearthpreponderatesinit。）Potteryconsistsofearthalonebecauseitsolidifiedgraduallyintheprocessofdrying。Watercannotgetintoit，fortheporeswereonlylargeenoughtoadmitofvapourescaping：andseeingthatfiresolidifiedit，thatcannotdissolveiteither。
Sosolidificationandmelting，theircauses，andthekindsofsubjectsinwhichtheyoccurhavebeendescribed。
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Allthismakesitclearthatbodiesareformedbyheatandcoldandthattheseagentsoperatebythickeningandsolidifying。Itisbecausethesequalitiesfashionbodiesthatwefindheatinallofthem，andinsomecoldinsofarasheatisabsent。Thesequalities，then，arepresentasactive，andthemoistandthedryaspassive，andconsequentlyallfourarefoundinmixedbodies。Sowaterandeartharetheconstituentsofhomogeneousbodiesbothinplantsandinanimalsandofmetalssuchasgold，silver，andtherest-waterandearthandtheirrespectiveexhalationsshutupinthecompoundbodies，aswehaveexplainedelsewhere。
Allthesemixedbodiesaredistinguishedfromoneanother，firstlybythequalitiesspecialtothevarioussenses，thatis，bytheircapacitiesofaction。（Forathingiswhite，fragrant，sonant，sweet，hot，coldinvirtueofapowerofactingonsense）。Secondlybyothermorecharacteristicaffectionswhichexpresstheiraptitudetobeaffected：Imean，forinstance，theaptitudetomeltorsolidifyorbendandsoforth，allthesequalities，likemoistanddry，beingpassive。Thesearethequalitiesthatdifferentiatebone，flesh，sinew，wood，bark，stoneandallotherhomogeneousnaturalbodies。Letusbeginbyenumeratingthesequalitiesexpressingtheaptitudeorinaptitudeofathingtobeaffectedinacertainway。Theyareasfollows：tobeaptorinapttosolidify，melt，besoftenedbyheat，besoftenedbywater，bend，break，becomminuted，impressed，moulded，squeezed;tobetractileornon-tractile，malleableornon-malleable，tobefissileornon-fissile，aptorinapttobecut;
tobeviscousorfriable，compressibleorincompressible，combustibleorincombustible;tobeaptorinapttogiveofffumes。
Theseaffectionsdifferentiatemostbodiesfromoneanother。Letusgoontoexplainthenatureofeachofthem。Wehavealreadygivenageneralaccountofthatwhichisaptorinapttosolidifyortomelt，butletusreturntothemagainnow。Ofallthebodiesthatadmitofsolidificationandhardening，somearebroughtintothisstatebyheat，othersbycold。Heatdoesthisbydryinguptheirmoisture，coldbydrivingouttheirheat。Consequentlysomebodiesareaffectedinthiswaybydefectofmoisture，somebydefectofheat：
waterybodiesbydefectofheat，earthybodiesofmoisture。Nowthosebodiesthataresoaffectedbydefectofmoisturearedissolvedbywater，unlesslikepotterytheyhavesocontractedthattheirporesaretoosmallfortheparticlesofwatertoenter。Allthosebodiesinwhichthisisnotthecasearedissolvedbywater，e。g。natron，salt，drymud。Thosebodiesthatsolidifiedthroughdefectofheataremeltedbyheat，e。g。ice，lead，copper。Somuchforthebodiesthatadmitofsolidificationandofmelting，andthosethatdonotadmitofmelting。
Thebodieswhichdonotadmitofsolidificationarethosewhichcontainnoaqueousmoistureandarenotwatery，butinwhichheatandearthpreponderate，likehoneyandmust（fortheseareinasortofstateofeffervescence），andthosewhichdopossesssomewaterbuthaveapreponderanceofair，likeoilandquicksilver，andallviscoussubstancessuchaspitchandbirdlime。
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Thosebodiesadmitofsofteningwhicharenot（likeice）madeupofwater，butinwhichearthpredominates。Alltheirmoisturemustnothaveleftthem（asinthecaseofnatronandsalt），normusttherelationofdrytomoistinthembeincongruous（asinthecaseofpottery）。Theymustbetractile（withoutadmittingwater）ormalleable（withoutconsistingofwater），andtheagentinsofteningthemisfire。Suchareironandhorn。
Bothofbodiesthatcanmeltandofbodiesthatcannot，somedoandsomedonotadmitofsofteninginwater。Copper，forinstance，whichcanbemelted，cannotbesoftenedinwater，whereaswoolandearthcanbesoftenedinwater，fortheycanbesoaked。（Itistruethatthoughcoppercanbemeltedtheagentinitscaseisnotwater，butsomeofthebodiesthatcanbemeltedbywatertoosuchasnatronandsaltcannotbesoftenedinwater：fornothingissaidtobesoaffectedunlessthewatersoaksintoitandmakesitsofter。）
Somethings，ontheotherhand，suchaswoolandgrain，canbesoftenedbywaterthoughtheycannotbemelted。Anybodythatistobesoftenedbywatermustbeofearthandmusthaveitsporeslargerthantheparticlesofwater，andtheporesthemselvesmustbeabletoresisttheactionofwater，whereasbodiesthatcanbe’melted’bywatermusthaveporesthroughout。
（Whyisitthatearthisboth’melted’andsoftenedbymoisture，whilenatronis’melted’butnotsoftened？Becausenatronispervadedthroughoutbyporessothatthepartsareimmediatelydividedbythewater，butearthhasalsoporeswhichdonotconnectandisthereforedifferentlyaffectedaccordingasthewaterentersbyoneortheothersetofpores。）
Somebodiescanbebentorstraightened，likethereedorthewithy，somecannot，likepotteryandstone。Thosebodiesareapttobebentandstraightenedwhichcanchangefrombeingcurvedtobeingstraightandfrombeingstraighttobeingcurved，andbendingandstraighteningconsistinthechangeormotiontothestraightortoacurve，forathingissaidtobeinprocessofbeingbentwhetheritisbeingmadetoassumeaconvexoraconcaveshape。Sobendingisdefinedasmotiontotheconvexortheconcavewithoutachangeoflength。Forifweadded’ortothestraight’，weshouldhaveathingbentandstraightatonce，anditisimpossibleforthatwhichisstraighttobebent。Andifallbendingisabendingbackorabendingdown，theformerbeingachangetotheconvex，thelattertotheconcave，amotionthatleadstothestraightcannotbecalledbending，butbendingandstraighteningaretwodifferentthings。These，then，arethethingsthatcan，andthosethatcannotbebent，andbestraightened。
Somethingscanbebothbrokenandcomminuted，othersadmitonlyoneortheother。Wood，forinstance，canbebrokenbutnotcomminuted，iceandstonecanbecomminutedbutnotbroken，whilepotterymayeitherbecomminutedorbroken。Thedistinctionisthis：breakingisadivisionandseparationintolargeparts，comminutionintopartsofanysize，buttheremustbemoreofthemthantwo。Nowthosesolidsthathavemanyporesnotcommunicatingwithoneanotherarecomminuible（forthelimittotheirsubdivisionissetbythepores），butthosewhoseporesstretchcontinuouslyforalongwayarebreakable，whilethosewhichhaveporesofbothkindsarebothcomminuibleandbreakable。
Somethings，e。g。copperandwax，areimpressible，others，e。g。
potteryandwater，arenot。Theprocessofbeingimpressedisthesinkingofapartofthesurfaceofathinginresponsetopressureorablow，ingeneraltocontact。Suchbodiesareeithersoft，likewax，wherepartofthesurfaceisdepressedwhiletherestremains，orhard，likecopper。Non-impressiblebodiesareeitherhard，likepottery（itssurfacedoesnotgivewayandsinkin），orliquid，likewater（forthoughwaterdoesgivewayitisnotinapartofit，forthereisareciprocalchangeofplaceofallitsparts）。Thoseimpressiblesthatretaintheshapeimpressedonthemandareeasilymouldedbythehandarecalled’plastic’;thosethatarenoteasilymoulded，suchasstoneorwood，orareeasilymouldedbutdonotretaintheshapeimpressed，likewoolorasponge，arenotplastic。
Thelastgrouparesaidtobe’squeezable’。Thingsare’squeezable’
whentheycancontractintothemselvesunderpressure，theirsurfacesinkinginwithoutbeingbrokenandwithoutthepartsinterchangingpositionashappensinthecaseofwater。（Wespeakofpressurewhenthereismovementandthemotorremainsincontactwiththethingmoved，ofimpactwhenthemovementisduetothelocalmovementofthemotor。）Thosebodiesaresubjecttosqueezingwhichhaveemptypores-empty，thatis，ofthestuffofwhichthebodyitselfconsists-andthatcansinkuponthevoidspaceswithinthem，orratherupontheirpores。Forsometimestheporesuponwhichabodysinksinarenotempty（awetsponge，forinstance，hasitsporesfull）。Butthepores，iffull，mustbefullofsomethingsofterthanthebodyitselfwhichistocontract。Examplesofthingssqueezablearethesponge，wax，flesh。Thosethingsarenotsqueezablewhichcannotbemadetocontractupontheirownporesbypressure，eitherbecausetheyhavenoporesorbecausetheirporesarefullofsomethingtoohard。
Thusiron，stone，waterandallliquidsareincapableofbeingsqueezed。
Thingsaretractilewhentheirsurfacecanbemadetoelongate，forbeingdrawnoutisamovementofthesurface，remainingunbroken，inthedirectionofthemover。Somethingsaretractile，e。g。hair，thongs，sinew，dough，birdlime，andsomearenot，e。g。
water，stone。Somethingsarebothtractileandsqueezable，e。g。wool;
inothercasesthetwoqualitiesdonotcoincide;phlegm，forinstance，istractilebutnotsqueezable，andaspongesqueezablebutnottractile。
Somethingsaremalleable，likecopper。Somearenot，likestoneandwood。Thingsaremalleablewhentheirsurfacecanbemadetomove（butonlyinpart）bothdownwardsandsidewayswithoneandthesameblow：whenthisisnotpossibleabodyisnotmalleable。Allmalleablebodiesareimpressible，butnotallimpressiblebodiesaremalleable，e。g。wood，thoughonthewholethetwogotogether。Ofsqueezablethingssomearemalleableandsomenot：waxandmudaremalleable，woolisnot。Somethingsarefissile，e。g。wood，somearenot，e。g。potter’sclay。Athingisfissilewhenitisapttodivideinadvanceoftheinstrumentdividingit，forabodyissaidtosplitwhenitdividestoafurtherpointthanthattowhichthedividinginstrumentdividesitandtheactofdivisionadvances：whichisnotthecasewithcutting。Thosebodieswhichcannotbehavelikethisarenon-fissile。Nothingsoftisfissile（bysoftImeanabsolutelysoftandnotrelatively：forironitselfmayberelativelysoft）;norareallhardthingsfissile，butonlysuchasareneitherliquidnorimpressiblenorcomminuible。Sucharethebodiesthathavetheporesalongwhichtheycoherelengthwiseandnotcrosswise。
Thosehardorsoftsolidsareapttobecutwhichdonotnecessarilyeithersplitinadvanceoftheinstrumentorbreakintominutefragmentswhentheyarebeingdivided。Thosethatnecessarilydosoandliquidscannotbecut。Somethingscanbebothsplitandcut，likewood，thoughgenerallyitislengthwisethatathingcanbesplitandcrosswisethatitcanbecut。For，abodybeingdividedintomanypartsfinsofarasitsunityismadeupofmanylengthsitisapttobesplit，insofarasitismadeupofmanybreadthsitisapttobecut。
Athingisviscouswhen，beingmoistorsoft，itistractile。Bodiesowethispropertytotheinterlockingoftheirpartswhentheyarecomposedlikechains，forthentheycanbedrawnouttoagreatlengthandcontractedagain。Bodiesthatarenotlikethisarefriable。
Bodiesarecompressiblewhentheyaresqueezableandretaintheshapetheyhavebeensqueezedinto;incompressiblewhentheyareeitherinapttobesqueezedatallordonotretaintheshapetheyhavebeensqueezedinto。
Somebodiesarecombustibleandsomearenot。Wood，wool，bonearecombustible;stone，icearenot。Bodiesarecombustiblewhentheirporesaresuchastoadmitfireandtheirlongitudinalporescontainmoistureweakerthanfire。Iftheyhavenomoisture，orif，asiniceorverygreenwood，themoistureisstrongerthanfire，theyarenotcombustible。
Thosebodiesgiveofffumeswhichcontainmoisture，butinsuchaformthatitdoesnotgooffseparatelyinvapourwhentheyareexposedtofire。Forvapourisamoistsecretiontendingtothenatureofairproducedfromaliquidbytheagencyofburningheat。Bodiesthatgiveofffumesgiveoffsecretionsofthenatureofairbythelapseoftime：astheyperishawaytheydryuporbecomeearth。Butthekindofsecretionweareconcernedwithnowdiffersfromothersinthatitisnotmoistnordoesitbecomewind（whichisacontinuousflowofairinagivendirection）。Fumesarecommonsecretionofdryandmoisttogethercausedbytheagencyofburningheat。Hencetheydonotmoistenthingsbutrathercolourthem。
Thefumesofawoodybodyarecalledsmoke。（Imeantoincludebonesandhairandeverythingofthiskindinthesameclass。ForthereisnonamecommontoalltheobjectsthatImean，but，forallthat，thesethingsareallinthesameclassbyanalogy。ComparewhatEmpedoclessays：Theyareoneandthesame，hairandleavesandthethickwingsofbirdsandscalesthatgrowonstoutlimbs。）Thefumesoffatareasootysmokeandthoseofoilysubstancesagreasysteam。Oildoesnotboilawayorthickenbyevaporationbecauseitdoesnotgiveoffvapourbutfumes。Waterontheotherhanddoesnotgiveofffumes，butvapour。Sweetwinedoesgiveofffumes，foritcontainsfatandbehaveslikeoil。Itdoesnotsolidifyundertheinfluenceofcoldanditisapttoburn。Reallyitisnotwineatallinspiteofitsname：foritdoesnottastelikewineandconsequentlydoesnotinebriateasordinarywinedoes。Itcontainsbutlittlefumigablestuffandconsequentlyisinflammable。
Allbodiesarecombustiblethatdissolveintoashes，andallbodiesdothisthatsolidifyundertheinfluenceeitherofheatorofbothheatandcold;forwefindthatallthesebodiesaremasteredbyfire。Ofstonesthepreciousstonecalledcarbuncleisleastamenabletofire。
Ofcombustiblebodiessomeareinflammableandsomearenot，andsomeoftheformerarereducedtocoals。Thosearecalled’inflammable’whichproduceflameandthosewhichdonotarecalled’non-inflammable’。Thosefumigablebodiesthatarenotliquidareinflammable，butpitch，oil，waxareinflammableinconjunctionwithotherbodiesratherthanbythemselves。Mostinflammablearethosebodiesthatgiveoffsmoke。Ofbodiesofthiskindthosethatcontainmoreearththansmokeareapttobereducedtocoals。Somebodiesthatcanbemeltedarenotinflammable，e。g。copper;andsomebodiesthatcannotbemeltedareinflammable，e。g。wood;andsomebodiescanbemeltedandarealsoinflammable，e。g。frankincense。
Thereasonisthatwoodhasitsmoisturealltogetherandthisiscontinuousthroughoutandsoitburnsup：whereascopperhasitineachpartbutnotcontinuous，andinsufficientinquantitytogiverisetoflame。Infrankincenseitisdisposedinbothoftheseways。
Fumigablebodiesareinflammablewhenearthpredominatesinthemandtheyareconsequentlysuchastobeunabletomelt。Theseareinflammablebecausetheyaredrylikefire。Whenthisdrycomestobehotthereisfire。Thisiswhyflameisburningsmokeordryexhalation。Thefumesofwoodaresmoke，thoseofwaxandfrankincenseandsuch-like，andpitchandwhatevercontainspitchorsuch-likearesootysmoke，whilethefumesofoilandoilysubstancesareagreasysteam;soarethoseofallsubstanceswhicharenotatallcombustiblebythemselvesbecausethereistoolittleofthedryinthem（thedrybeingthemeansbywhichthetransitiontofireiseffected），butburnveryreadilyinconjunctionwithsomethingelse。
（Forthefatisjusttheconjunctionoftheoilywiththedry。）Sothosebodiesthatgiveofffumes，likeoilandpitch，belongrathertothemoist，butthosethatburntothedry。
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Homogeneousbodiesdiffertotouch-bytheseaffectionsanddifferences，aswehavesaid。Theyalsodifferinrespectoftheirsmell，taste，andcolour。
ByhomogeneousbodiesImean，forinstance，’metals’，gold，copper，silver，tin，iron，stone，andeverythingelseofthiskindandthebodiesthatareextractedfromthem;alsothesubstancesfoundinanimalsandplants，forinstance，flesh，bones，sinew，skin，viscera，hair，fibres，veins（thesearetheelementsofwhichthenon-homogeneousbodiesliketheface，ahand，afoot，andeverythingofthatkindaremadeup），andinplants，wood，bark，leaves，roots，andtherestlikethem。
Thehomogeneousbodies，itistrue，areconstitutedbyadifferentcause，butthematterofwhichtheyarecomposedisthedryandthemoist，thatis，waterandearth（forthesebodiesexhibitthosequalitiesmostclearly）。Theagentsarethehotandthecold，fortheyconstituteandmakeconcretethehomogeneousbodiesoutofearthandwaterasmatter。Letusconsider，then，whichofthehomogeneousbodiesaremadeofearthandwhichofwater，andwhichofboth。
Oforganizedbodiessomeareliquid，somesoft，somehard。Thesoftandthehardareconstitutedbyaprocessofsolidification，aswehavealreadyexplained。
Thoseliquidsthatgooffinvapouraremadeofwater，thosethatdonotareeitherofthenatureofearth，oramixtureeitherofearthandwater，likemilk，orofearthandair，likewood，orofwaterandair，likeoil。Thoseliquidswhicharethickenedbyheatareamixture。（Wineisaliquidwhichraisesadifficulty：foritisbothliabletoevaporationanditalsothickens;forinstancenewwinedoes。Thereasonisthattheword’wine’isambiguousanddifferent’wines’behaveindifferentways。Newwineismoreearthythanold，andforthisreasonitismoreapttobethickenedbyheatandlessapttobecongealedbycold。Foritcontainsmuchheatandagreatproportionofearth，asinArcadia，whereitissodriedupinitsskinsbythesmokethatyouscrapeittodrink。Ifallwinehassomesedimentinitthenitwillbelongtoearthortowateraccordingtothequantityofthesedimentitpossesses。）Theliquidsthatarethickenedbycoldareofthenatureofearth;thosethatarethickenedeitherbyheatorbycoldconsistofmorethanoneelement，likeoilandhoney，and’sweetwine’。
Ofsolidbodiesthosethathavebeensolidifiedbycoldareofwater，e。g。ice，snow，hail，hoar-frost。Thosesolidifiedbyheatareofearth，e。g。pottery，cheese，natron，salt。Somebodiesaresolidifiedbybothheatandcold。Ofthiskindarethosesolidifiedbyrefrigeration，thatisbytheprivationbothofheatandofthemoisturewhichdepartswiththeheat。Forsaltandthebodiesthatarepurelyofearthsolidifybytheprivationofmoistureonly，icebythatofheatonly，thesebodiesbythatofboth。Soboththeactivequalitiesandbothkindsofmatterwereinvolvedintheprocess。Ofthesebodiesthosefromwhichallthemoisturehasgoneareallofthemofearth，likepotteryoramber。（Foramber，also，andthebodiescalled’tears’areformedbyrefrigeration，likemyrrh，frankincense，gum。Amber，too，appearstobelongtothisclassofthings：theanimalsenclosedinitshowthatitisformedbysolidification。Theheatisdrivenoutofitbythecoldoftheriverandcausesthemoisturetoevaporatewithit，asinthecaseofhoneywhenithasbeenheatedandisimmersedinwater。）Someofthesebodiescannotbemeltedorsoftened;forinstance，amberandcertainstones，e。g。thestalactitesincaves。（Forthesestalactites，too，areformedinthesameway：theagentisnotfire，butcoldwhichdrivesouttheheat，which，asitleavesthebody，drawsoutthemoisturewithit：intheotherclassofbodiestheagentisexternalfire。）Inthosefromwhichthemoisturehasnotwhollygoneearthstillpreponderates，buttheyadmitofsofteningbyheat，e。g。ironandhorn。
Nowsincewemustincludeamong’meltables’thosebodieswhicharemeltedbyfire，thesecontainsomewater：indeedsomeofthem，likewax，arecommontoearthandwateralike。Butthosethataremeltedbywaterareofearth。Thosethatarenotmeltedeitherbyfireorwaterareofearth，orofearthandwater。
Since，then，allbodiesareeitherliquidorsolid，andsincethethingsthatdisplaytheaffectionswehaveenumeratedbelongtothesetwoclassesandthereisnothingintermediate，itfollowsthatwehavegivenacompleteaccountofthecriteriafordistinguishingwhetherabodyconsistsofearthorofwaterorofmoreelementsthanone，andwhetherfirewastheagentinitsformation，orcold，orboth。
Gold，then，andsilverandcopperandtinandleadandglassandmanynamelessstoneareofwater：fortheyareallmeltedbyheat。
Ofwater，too，aresomewinesandurineandvinegarandlyeandwheyandserum：fortheyareallcongealedbycold。Iniron，horn，nails，bones，sinews，wood，hair，leaves，bark，earthpreponderates。So，too，inamber，myrrh，frankincense，andallthesubstancescalled’tears’，andstalactites，andfruits，suchasleguminousplantsandcorn。Forthingsofthiskindare，toagreaterorlessdegree，ofearth。Forofallthesebodiessomeadmitofsofteningbyheat，therestgiveofffumesandareformedbyrefrigeration。Soagaininnatron，salt，andthosekindsofstonesthatarenotformedbyrefrigerationandcannotbemelted。Blood，ontheotherhand，andsemen，aremadeupofearthandwaterandair。Ifthebloodcontainsfibres，earthpreponderatesinit：consequentlyitssolidifiesbyrefrigerationandismeltedbyliquids;ifnot，itisofwaterandthereforedoesnotsolidify。Semensolidifiesbyrefrigeration，itsmoistureleavingittogetherwithitsheat。
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Wemustinvestigateinthelightoftheresultswehavearrivedatwhatsolidorliquidbodiesarehotandwhatcold。
Bodiesconsistingofwaterarecommonlycold，unless（likelye，urine，wine）theycontainforeignheat。Bodiesconsistingofearth，ontheotherhand，arecommonlyhotbecauseheatwasactiveinformingthem：forinstancelimeandashes。
Wemustrecognizethatcoldisinasensethematterofbodies。
Forthedryandthemoistarematter（beingpassive）andearthandwateraretheelementsthatprimarilyembodythem，andtheyarecharacterizedbycold。Consequentlycoldmustpredominateineverybodythatconsistsofoneorotheroftheelementssimply，unlesssuchabodycontainsforeignheataswaterdoeswhenitboilsorwhenithasbeenstrainedthroughashes。Thislatter，too，hasacquiredheatfromtheashes，foreverythingthathasbeenburntcontainsmoreorlessheat。Thisexplainsthegenerationofanimalsinputrefyingbodies：theputrefyingbodycontainstheheatwhichdestroyeditsproperheat。
Bodiesmadeupofearthandwaterarehot，formostofthemderivetheirexistencefromconcoctionandheat，thoughsome，likethewasteproductsofthebody，areproductsofputrefaction。Thusblood，semen，marrow，figjuice，andallthingsofthekindsarehotaslongastheyareintheirnaturalstate，butwhentheyperishandfallawayfromthatstatetheyaresonolonger。Forwhatisleftofthemistheirmatterandthatisearthandwater。Hencebothviewsareheldaboutthem，somepeoplemaintainingthemtobecoldandotherstobewarm;fortheyareobservedtobehotwhentheyareintheirnaturalstate，buttosolidifywhentheyhavefallenawayfromit。That，then，isthecaseofmixedbodies。However，thedistinctionwelaiddownholdsgood：ifitsmatterispredominantlywaterabodyiscold（waterbeingthecompleteoppositeoffire），butifearthorairittendstobewarm。
Itsometimeshappensthatthecoldestbodiescanberaisedtothehighesttemperaturebyforeignheat;forthemostsolidandthehardestbodiesarecoldestwhendeprivedofheatandmostburningafterexposuretofire：thuswaterismoreburningthansmokeandstonethanwater。
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Havingexplainedallthiswemustdescribethenatureofflesh，bone，andtheotherhomogeneousbodiesseverally。
Ouraccountoftheformationofthehomogeneousbodieshasgivenustheelementsoutofwhichtheyarecompoundedandtheclassesintowhichtheyfall，andhasmadeitcleartowhichclasseachofthosebodiesbelongs。Thehomogeneousbodiesaremadeupoftheelements，andalltheworksofnatureinturnofthehomogeneousbodiesasmatter。Allthehomogeneousbodiesconsistoftheelementsdescribed，asmatter，buttheiressentialnatureisdeterminedbytheirdefinition。Thisfactisalwaysclearerinthecaseofthelaterproductsofthose，infact，thatareinstruments，asitwere，andhaveanend：itisclearer，forinstance，thatadeadmanisamanonlyinname。Andsothehandofadeadman，too，willinthesamewaybeahandinnameonly，justasstoneflutesmightstillbecalledflutes：forthesemembers，too，areinstrumentsofakind。Butinthecaseoffleshandbonethefactisnotsocleartosee，andinthatoffireandwaterevenless。Fortheendisleastobvioustherewherematterpredominatesmost。Ifyoutaketheextremes，matterispurematterandtheessenceispuredefinition;butthebodiesintermediatebetweenthetwoarematterordefinitioninproportionastheyareneartoeither。Foreachofthoseelementshasanendandisnotwaterorfireinanyandeveryconditionofitself，justasfleshisnotfleshnorvisceraviscera，andthesameistrueinahigherdegreewithfaceandhand。Whatathingisalwaysdeterminedbyitsfunction：athingreallyisitselfwhenitcanperformitsfunction;aneye，forinstance，whenitcansee。Whenathingcannotdosoitisthatthingonlyinname，likeadeadeyeoronemadeofstone，justasawoodensawisnomoreasawthanoneinapicture。
Thesame，then，istrueofflesh，exceptthatitsfunctionislessclearthanthatofthetongue。So，too，withfire;butitsfunctionisperhapsevenhardertospecifybyphysicalinquirythanthatofflesh。
Thepartsofplants，andinanimatebodieslikecopperandsilver，areinthesamecase。Theyallarewhattheyareinvirtueofacertainpowerofactionorpassion-justlikefleshandsinew。Butwecannotstatetheirformaccurately，andsoitisnoteasytotellwhentheyarereallythereandwhentheyarenotunlessthebodyisthoroughlycorruptedanditsshapeonlyremains。Soancientcorpsessuddenlybecomeashesinthegraveandveryoldfruitpreservesitsshapeonlybutnotitstaste：so，too，withthesolidsthatformfrommilk。
Nowheatandcoldandthemotionstheysetupasthebodiesaresolidifiedbythehotandthecoldaresufficienttoformallsuchpartsasarethehomogeneousbodies，flesh，bone，hair，sinew，andtherest。Fortheyareallofthemdifferentiatedbythevariousqualitiesenumeratedabove，tension，tractility，comminuibility，hardness，softness，andtherestofthem：allofwhicharederivedfromthehotandthecoldandthemixtureoftheirmotions。Butnoonewouldgoasfarastoconsiderthemsufficientinthecaseofthenon-homogeneousparts（likethehead，thehand，orthefoot）whichthesehomogeneouspartsgotomakeup。Coldandheatandtheirmotionwouldbeadmittedtoaccountfortheformationofcopperorsilver，butnotforthatofasaw，abowl，orabox。Sohere，savethatintheexamplesgiventhecauseisart，butinthenonhomogeneousbodiesnatureorsomeothercause。
Since，then，weknowtowhatelementeachofthehomogeneousbodiesbelongs，wemustnowfindthedefinitionofeachofthem，theanswer，thatis，tothequestion，’whatis’flesh，semen，andtherest？Forweknowthecauseofathinganditsdefinitionwhenweknowthematerialortheformalor，better，boththematerialandtheformalconditionsofitsgenerationanddestruction，andtheefficientcauseofit。
Afterthehomogeneousbodieshavebeenexplainedwemustconsiderthenon-homogeneoustoo，andlastlythebodiesmadeupofthese，suchasman，plants，andtherest。