Therearethreevarieties，spiral，univalve，andbivalve。
Ineverysalt-paninthecountrythereisaspringofwaterononeside。
IcanremembernoexceptiontothisruleThewaterofthesespringsisbrackish，andcontainsthenitrateofsodaInoneinstancetherearetwosprings，andonemoresaltishthantheother。
Ifthissupplycamefrombedsofrocksaltthewaterwouldnotbedrinkable，asitgenerallyis，andinsomeinstances，wherethesaltcontainedinthepaninwhichthesespringsappearhasbeenremovedbyhumanagency，nofreshdepositoccursItisthereforeprobablethatthesedepositsofsaltaretheremainsoftheveryslightlybrackishlakesofantiquity，largeportionsofwhichmusthavebeendriedoutinthegeneraldesiccation。
WeseeaninstanceinLakeNgami，which，whenlow，becomesbrackish，andthisviewseemssupportedbythefactthatthelargestquantitiesofsalthavebeenfoundinthedeepesthollowsorlowestvalleys，whichhavenooutletoroutgoinggorge；andafountain，aboutthirtymilessouthoftheBamangwatothetemperatureofwhichisupwardof100Degwhilestronglyimpregnatedwithpuresalt，beingonaflatpartofthecountry，isaccompaniedbynodeposit。
Whenthesedepositsoccurinaflattufaceouscountrylikethepresent，alargespaceisdevoidofvegetation，onaccountofthenitratesdissolvingthetufa，andkeepingitinastateunfavorabletothegrowthofplants。
WefoundagreatnumberofwellsinthistufaAplacecalledMatlomagan-yana，orthe“Links“，isquiteachainofthesenever-failingspringsAstheyoccasionallybecomefullinseasonswhennorainfalls，andresemblesomewhatinthisrespecttheriverswehavealreadymentioned，itisprobabletheyreceivesomewaterbypercolationfromtheriversysteminthecountrybeyondAmongtheselinkswefoundmanyfamiliesofBushmen；and，unlikethoseontheplainsoftheKalahari，whoaregenerallyofshortstatureandlightyellowcolor，theseweretall，strappingfellows，ofdarkcomplexionHeatalonedoesnotproduceblacknessofskin，butheatwithmoistureseemstoinsurethedeepesthue。
OneoftheseBushmen，namedShobo，consentedtobeourguideoverthewastebetweenthesespringsandthecountryofSebituane。
ShobogaveusnohopeofwaterinlessthanamonthProvidentially，however，wecamesoonerthanweexpectedtosomesuppliesofrain-waterinachainofpoolsItisimpossibletoconveyanideaofthedrearysceneonwhichweenteredafterleavingthisspot：theonlyvegetationwasalowscrubindeepsand；notabirdorinsectenlivenedthelandscape。
Itwas，withoutexception，themostuninvitingprospectIeverbeheld；
and，tomakemattersworse，ourguideShobowanderedonthesecondday。
Wecoaxedhimonatnight，buthewenttoallpointsofthecompassonthetrailsofelephantswhichhadbeenhereintherainyseason，andthenwouldsitdowninthepath，andinhisbrokenSichuanasay，“Nowater，allcountryonly；Shobosleeps；hebreaksdown；countryonly；“
andthencoollycurlhimselfupandgotosleepTheoxenwereterriblyfatiguedandthirsty；andonthemorningofthefourthday，Shobo，afterprofessingignoranceofeverything，vanishedaltogether。
Wewentoninthedirectioninwhichwelastsawhim，andabouteleveno’clockbegantoseebirds；thenthetrailofarhinoceros。
Atthisweunyokedtheoxen，andthey，apparentlyknowingthesign，rushedalongtofindthewaterintheRiverMahabe，whichcomesfromtheTamunak’le，andlaytothewestofusThesupplyofwaterinthewagonshadbeenwastedbyoneofourservants，andbytheafternoononlyasmallportionremainedforthechildrenThiswasabitterlyanxiousnight；
andnextmorningthelesstherewasofwater，themorethirstythelittleroguesbecameTheideaoftheirperishingbeforeoureyeswasterribleItwouldalmosthavebeenarelieftometohavebeenreproachedwithbeingtheentirecauseofthecatastrophe；
butnotonesyllableofupbraidingwasutteredbytheirmother，thoughthetearfuleyetoldtheagonywithinIntheafternoonofthefifthday，toourinexpressiblerelief，someofthemenreturnedwithasupplyofthatfluidofwhichwehadneverbeforefeltthetruevalue。
Thecattle，inrushingalongtothewaterintheMahabe，probablycrossedasmallpatchoftreescontainingtsetse，aninsectwhichwasshortlytobecomeaperfectpesttous。
ShobohadfoundhiswaytotheBayeiye，andappeared，whenwecameuptotheriver，attheheadofaparty；and，ashewishedtoshowhisimportancebeforehisfriends，hewalkedupboldlyandcommandedourwholecavalcadetostop，andtobringforthfireandtobacco，whilehecoollysatdownandsmokedhispipe。
Itwassuchaninimitablynaturalwayofshowingoff，thatweallstoppedtoadmiretheacting，and，thoughhehadleftuspreviouslyinthelurch，wealllikedShobo，afinespecimenofthatwonderfulpeople，theBushmen。
NextdaywecametoavillageofBanajoa，atribewhichextendsfartotheeastwardTheywerelivingonthebordersofamarshinwhichtheMahabeterminatesTheyhadlosttheircropofcorn`Holcussorghum’，andnowsubsistedalmostentirelyontherootcalled“tsitla“，akindofaroidoea，whichcontainsaverylargequantityofsweet-tastedstarchWhendried，poundedintomeal，andallowedtoferment，itformsanotunpleasantarticleoffoodThewomenshaveallthehairofftheirheads，andseemdarkerthantheBechuanasTheirhutswerebuiltonpoles，andafireismadebeneathbynight，inorderthatthesmokemaydriveawaythemosquitoes，whichaboundontheMababeandTamunak’lemorethaninanyotherpartofthecountryTheheadmanofthisvillage，Majane，seemedalittlewantinginability，buthadhadwitenoughtopromoteayoungermemberofthefamilytotheofficeThisperson，themostliketheuglynegroofthetobacconists’shopsIeversaw，wascalledMoroaMajane，orsonofMajane，andprovedanactiveguideacrosstheRiverSonta，andtothebanksoftheChobe，inthecountryofSebituaneWehadcomethroughanothertsetsedistrictbynight，andatoncepassedourcattleovertothenorthernbanktopreservethemfromitsravages。
AfewremarksontheTsetse，or`Glossinamorsitans’，mayherebeappropriate。
Itisnotmuchlargerthanthecommonhouse-fly，andisnearlyofthesamebrowncolorasthecommonhoney-bee；theafterpartofthebodyhasthreeorfouryellowbarsacrossit；thewingsprojectbeyondthispartconsiderably，anditisremarkablyalert，avoidingmostdexterouslyallattemptstocaptureitwiththehandatcommontemperatures；inthecoolofthemorningsandeveningsitislessagileItspeculiarbuzzwhenonceheardcanneverbeforgottenbythetravelerwhosemeansoflocomotionaredomesticanimals；
foritiswellknownthatthebiteofthispoisonousinsectiscertaindeathtotheox，horse，anddogInthisjourney，thoughwewerenotawareofanygreatnumberhavingatanytimelightedonourcattle，welostforty-threefineoxenbyitsbite。
Wewatchedtheanimalscarefully，andbelievethatnotascoreofflieswereeveruponthem。
Amostremarkablefeatureinthebiteofthetsetseisitsperfectharmlessnessinmanandwildanimals，andevencalves，solongastheycontinuetosuckthecowsWeneverexperiencedtheslightestinjuryfromthemourselves，personally，althoughwelivedtwomonthsintheirHABITAT，whichwasinthiscaseassharplydefinedasinmanyothers，forthesouthbankoftheChobewasinfestedbythem，andthenorthernbank，whereourcattlewereplaced，onlyfiftyyardsdistant，containednotasinglespecimenThiswasthemoreremarkable，asweoftensawnativescarryingoverrawmeattotheoppositebankwithmanytsetsesettleduponit。
Thepoisondoesnotseemtobeinjectedbyasting，orbyovaplacedbeneaththeskin；for，whenoneisallowedtofeedfreelyonthehand，itisseentoinsertthemiddleprongofthreeportions，intowhichtheproboscisdivides，somewhatdeeplyintothetrueskin；
itthendrawsitoutalittleway，anditassumesacrimsoncolorasthemandiblescomeintobriskoperationThepreviouslyshrunkenbellyswellsout，and，ifleftundisturbed，theflyquietlydepartswhenitisfullAslightitchingirritationfollows，butnotmorethaninthebiteofamosquitoIntheoxthissamebiteproducesnomoreimmediateeffectsthaninmanItdoesnotstartlehimasthegad-flydoes；
butafewdaysafterwardthefollowingsymptomssupervene：
theeyeandnosebegintorun，thecoatstaresasiftheanimalwerecold，aswellingappearsunderthejaw，andsometimesatthenavel；
and，thoughtheanimalcontinuestograze，emaciationcommences，accompaniedwithapeculiarflaccidityofthemuscles，andthisproceedsuncheckeduntil，perhapsmonthsafterward，purgingcomeson，andtheanimal，nolongerabletograze，perishesinastateofextremeexhaustionThosewhichareingoodconditionoftenperishsoonafterthebiteisinflictedwithstaggeringandblindness，asifthebrainwereaffectedbyitSuddenchangesoftemperatureproducedbyfallsofrainseemtohastentheprogressofthecomplaint；
but，ingeneral，theemaciationgoesonuninterruptedlyformonths，and，dowhatwewill，thepooranimalsperishmiserably。
Whenopened，thecellulartissueonthesurfaceofthebodybeneaththeskinisseentobeinjectedwithair，asifaquantityofsoap-bubbleswerescatteredoverit，oradishonest，awkwardbutcherhadbeentryingtomakeitlookfatThefatisofagreenish-yellowcolorandofanoilyconsistence。
Allthemusclesareflabby，andtheheartoftensosoftthatthefingersmaybemadetomeetthroughitThelungsandliverpartakeofthedisease。
Thestomachandbowelsarepaleandempty，andthegall-bladderisdistendedwithbile。
Thesesymptomsseemtoindicatewhatisprobablythecase，apoisonintheblood，thegermofwhichenterswhentheproboscisisinsertedtodrawbloodThepoison-germ，containedinabulbattherootoftheproboscis，seemscapable，althoughveryminuteinquantity，ofreproducingitself，forthebloodafterdeathbytsetseisverysmallinquantity，andscarcelystainsthehandsindissection。
Ishallhaveby-and-bytomentionanotherinsect，whichbythesameoperationproducesinthehumansubjectbothvomitingandpurging。
Themule，ass，andgoatenjoythesameimmunityfromthetsetseasmanandthegameManylargetribesontheZambesicankeepnodomesticanimalsexceptthegoat，inconsequenceofthescourgeexistingintheircountryOurchildrenwerefrequentlybitten，yetsufferednoharm；andwesawaroundusnumbersofzebras，buffaloes，pigs，pallahsandotherantelopes，feedingquietlyintheveryhabitatofthetsetse，yetasundisturbedbyitsbiteasoxenarewhentheyfirstreceivethefatalpoisonThereisnotsomuchdifferenceinthenaturesofthehorseandzebra，thebuffaloandox，thesheepandantelope，astoaffordanysatisfactoryexplanationofthephenomenonIsamannotasmuchadomesticanimalasadog？
Thecuriousfeatureinthecase，thatdogsperishthoughfedonmilk，whereasthecalvesescapesolongastheycontinuesucking，madeusimaginethatthemischiefmightbeproducedbysomeplantinthelocality，andnotbytsetse；butMajorVardon，oftheMadrasArmy，settledthatpointbyridingahorseuptoasmallhillinfestedbytheinsectwithoutallowinghimtimetograze，and，thoughheonlyremainedlongenoughtotakeaviewofthecountryandcatchsomespecimensoftsetseontheanimal，intendaysafterwardthehorsewasdead。
Thewell-knowndisgustwhichthetsetseshowstoanimalexcreta，asexhibitedwhenavillageisplacedinitshabitat，hasbeenobservedandturnedtoaccountbysomeofthedoctors。
Theymixdroppingsofanimals，humanmilk，andsomemedicinestogether，andsmeartheanimalsthatareabouttopassthroughatsetsedistrict；
butthis，thoughitprovesapreventiveatthetime，isnotpermanent。
ThereisnocureyetknownforthediseaseAcarelessherdsmanallowingalargenumberofcattletowanderintoatsetsedistrictlosesallexceptthecalves；andSebituaneoncelostnearlytheentirecattleofhistribe，verymanythousands，byunwittinglycomingunderitsinfluenceInoculationdoesnotinsureimmunity，asanimalswhichhavebeenslightlybitteninoneyearmayperishbyagreaternumberofbitesinthenext；butitisprobablethatwiththeincreaseofgunsthegamewillperish，ashashappenedinthesouth，andthetsetse，deprivedoffood，maybecomeextinctsimultaneouslywiththelargeranimals。
TheMakololowhomwemetontheChobeweredelightedtoseeus；
andastheirchiefSebituanewasabouttwentymilesdowntheriver，MrOswellandIproceededincanoestohistemporaryresidence。
HehadcomefromtheBarotsetownofNalieledowntoSeshekeassoonasheheardofwhitemenbeinginsearchofhim，andnowcameonehundredmilesmoretobiduswelcomeintohiscountry。
Hewasuponanisland，withallhisprincipalmenaroundhim，andengagedinsingingwhenwearrivedItwasmorelikechurchmusicthanthesing-songeeeeee，aeaeae，oftheBechuanasofthesouth，andtheycontinuedthetuneforsomesecondsafterweapproached。