ÿWPCž ½‘i›4EXÄ4EXÄ^á üðÛe™W3è~)6Ä ß0¯õ-xjöPþP)ÒÎA'‰vm$ÚÙ3EÏ8h­’Mø6.îòK¹§‚æ‰Òlc¿o‘U#˜³¨x÷Îx'j\`Žoô8C!ãÕöØBô£½VYJQ—º1ÞðÕ0ÔMA¼CΪn †îLDݧ²þÔ}:ÜTxÏ綃Çdqà ?‡`c¿;¢rÃ÷7ov2=ÀËq¾‡ÚC‹ ¨,5q˜*ÿ€7iWIy„¯ÅíVù=¥¾Ø#ÉÐ UN™ %ç 0:í^ 'U>3U@qw±4µÉØ mÚ¥ñ 0ED– 0EyÚÅS‡Ÿ‡µ‡<ÃÙ$ßö¹ù­²!Ï_" 0~.#•¬#³A'A'A' 0Dô'(8(g`+`+@Ç/Ç/Ç/Ç/Ð3333ð×3×3×3«Ç5Ç5Ç5ör6r6r6$h7õŒ9{::Îü;ü;·Ê<Ê<Î=qO>qÀ>À>À>À>N1?1?1?1?1?1?1?1?1?1?1?1?1?1?1?1?1?1?1?1?1? B3?3?3?3?3?3?3?3?3?™P?Âé@”«A+?H½jM^'N'N#…T…T¨¨X¨XPPZ‚ ]"a$5eXYf«±g±g±g_\h„»l»l£?sÁâss£t°w´ÆwÁzxzxë;yÊ&zqðzÁa{ "|-xEEEEk½ƒ½ƒ½ƒ½ƒ½ƒ§(‡(‡(‡(‡(‡(‡(‡(‡˜χχχχχχχχχχχχχχχχχχχχχχχχχχ=g‹g‹g‹g‹g‹g‹g‹q¤+‘‘‘‘º@’@’@’@’@’@’@’ú—ú—[ý™ý™ý™ý™ X›X›X›X›X›X›X›X›X›X›X›X›X›X›žcœ˜HP LaserJet 2200 Series PCL 6ÈÈÈÈÈÈÈÈ0(ÖÃ9 Z‹6Times New Roman RegularX(ö\$¡¡ÔCEUS.,ÔA¦„3— ô\  `&Times New Roman(ÖÃ9 Z‹(Times New Roman Äct.ÅÊ3|x ÿU‹ÿÀÀÀ ›Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú1Ú  Ú.Ý  ÝÔ_Ô€The€three€friends€were€ð ðMr.€Stocks,€Mr.€Snow,€and€Mr.€Fenneyðð;€ð ðLetter€from€Mr.€J.Ð ° ÐRobinson,€Surgeon„Dentist€to€the€Metropolitan€Hospital,ðð€òòMTóó€15€(2€January€1847):€274.€ForÐ ‰ œ Ðparticulars€on€Robinsonððs€life€and€training,€see€Richard€H.€Ellis,€ð ðJames€Robinson,€EnglandððsÐ u ˆ ÐTrue€Pioneer€of€Anaesthesia,ðð€in€The€History€of€Ô_ÔAnesthesiaÔ_Ô,€Third€International€Symposium,Ð a t ÐòòProceedingsóó€(Park€Ridge,€IL:€Wood€Library„Museum,€1992),€153„64.($Ó$‘‘òòÚ  Ú0Ú  Úóó(.#2V¿$¥¥Ý ƒö\!ÝÔCEUS.,ÔÝ  Ýà  àÚ  Ú0Ú  Ú. »Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú3Ú  Ú.Ý  ÝÔ_Ô€We€have€constructed€a€scenario€based€on€James€Robinson,€òòTreatiseóó,€8„9,€13„14,€16„19. }Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú4Ú  Ú.Ý  ÝÔ_Ô€Robinson,€òòTreatiseóó,€8. Ñ „ Ñ }Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú5Ú  Ú.Ý  ÝÔ_Ô€Robinson,€òòTreatiseóó,€8. }Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú6Ú  Ú.Ý  ÝÔ_Ô€Robinson,€òòTreatiseóó,€8. Ñ ° Ñ üÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú8Ú  Ú.Ý  ÝÔ_Ô€ð ðMedical€Intelligence:€Animal€magnetism€superseded€ð"ðdiscovery€of€a€newÐ ™¬ Ðhynopoietic,ðð€òòLMGóó€38€(18€December€1846):€1085„86. Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú14Ú  Ú.Ý  ÝÔ_Ô€ð ðPainless€surgical€operations,ðð€òòMTóó€15€(2€January€1847):€271.€Robinson€had€aÐ ÉÉ Ðdifferent€opinion€of€his€first€inhaler,€used€initially€on€19€December.€He€referred€later€to€it€as€ð ðaÐ µµ Ðvery€imperfect€apparatus,€hastily€got€up.ðð€Although€it€worked€adequately€on€Miss€Lonsdale,€heÐ ¡¡ Ðwas€unable€to€produce€complete€insensibility€in€several€patients€the€following€day;€Robinson,Ð  ÐòòTreatiseóó,€5.€See€also€David€Zuck,€ð ðWilliam€Hooper€(1818„1878)€and€the€Early€Weeks€ofÐ yy ÐAnaesthesia€in€England,ðð€in€History€of€Anaesthesia€Society,€òòProceedingsóó€34€(2004):€48„60.Ð ee Ð ìÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú7Ú  Ú.Ý  ÝÔ_Ô€Robinson,€òòTreatiseóó,€8;€ð ðLetter€from€Mr.€J.€Robinson,ðð€òòMTóó€15€(2€January€1847):€274;Ð ù  ÐòòTreatiseóó,€8. ¯Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú9Ú  Ú.Ý  ÝÔ_Ô€J.€Chitty€Clendon,€Letter€to€the€Editor,€òòLancetóó€1€(1847):€50;€ð ðApparatus€for€inhalingÐ 9"L Ðether,ðð€òòPharJóó€6€(1846„47):€338.€The€editors€of€òòPharJóó€also€stated€that€ð ðwe€are€informed€that€Dr.€A.Ð %#8 ÐT.€Thomson€has€been€in€the€habit€of€exhibiting€to€his€class€the€effects€of€ether€when€inhaled,€inÐ $$ Ðorder€to€demonstrate€the€analogy€in€its€effects€with€that€of€the€nitrous€oxide€gas.€The€practice€hasÐ ý$  Ðrecently€been€discontinued,€as€it€was€found€to€irritate€the€lungs€of€some€persons,€and€in€one€caseÐ é%ü  Ðproduced€inflammation.€Mr.€Squire€[the€chemist]€considers€that€this€arose€from€the€ether€notÐ Õ&è! Ðhaving€been€previously€washed€with€waterðð;€Ibid.€Anthony€Thomson€was€Professor€of€MateriaÐ Á'Ô" ÐMedica€and€Therapeutics,€as€well€as€Forensic€Science,€at€University€College€and€Physician€toÐ ­(À# ÐUniversity€College€Hospital;€òòMedical€Directoryóó€(1846).€He€was€also€a€colleague€of€Snowððs€at€theÐ ™)¬$ ÐWestminster€Medical€Society. £Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú15Ú  Ú.Ý  ÝÔ_Ô€ð ðPainless€operations,ðð€€òòMTóó€15€(9€January€1847):€290.€ ÅÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú40Ú  Ú.Ý  ÝÔ_Ô€ð ðOperations€without€Pain.€St.€Georgeððs€Hospital,ðð€òòLanceóót€1€(13€February€1847):€184.€(.(3M($¤¤Ý ƒö\!ÝÔCEUS.,ÔÝ  Ýà  àòòÚ  Ú0Ú  Úóó ‹Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú12Ú  Ú.Ý  ÝÔ_Ô€ð ðMedical€Intelligence.€Performance€of€surgical€operations€during€the€state€ofÐ Q Q  Ðnarcotism€from€ether,ðð€òòLMGóó€39€(1847):€38„39;€Mr.€Squireððs€inhaler€ð ðconsisted€of€the€bottom€partÐ = =  Ðof€a€Noothððs€Apparatus€.€.€.€and€one€of€Readððs€flexible€inhaling€tubesðð€(39).€ð ðThe€sedative€effectÐ ) )  Ðof€ether€tested€in€the€operating€theatre€of€the€North€London€Hospital,ðð€[previous€name€forÐ    ÐUniversity€College€Hospital]€òòPharJóó€6€(1846„47):€337„38;€the€editor€noted€that€ð ðwe€have€beenÐ  Ðinformed€that€some€experiments€have€been€made€at€other€hospitals,€but€hitherto€with€less€markedÐ íí Ðsuccess€.€.€.ðð€(338).€An€engraving€of€Squireððs€apparatus€appeared€on€the€same€page.ò òó ó ©Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú10Ú  Ú.Ý  ÝÔ_Ô€John€Snow,€ð ðCirculation€of€capillary€blood-vesselsðð€(1843),€813.€(#Ã$òòÚ  Ú0Ú  Úóó Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú26Ú  Ú.Ý  ÝÔ_Ô€ð ðWestminster€Medical€Society,ðð€òòLancetóó€1€(30€January€1847):€120„21.€Tracy€was€anÐ ÕÕ Ðunqualified€Surgeon„Dentist€to€St.€Bartholomew's€Hospital€at€the€time€who€quickly€began€toÐ ÁÁ Ðspecialize€in€anaesthesia;€he€administered€ether€for€the€first€Caesarian€section€described€as€beingÐ ­­ Ðperformed€under€ether€anaesthesia,€in€January€1847;€S.€J.€Tracy,€ð ðThe€use€of€ether€vapour€inÐ ™™ Ðsurgical€operations,ðð€òòLMGóó€39€(5€February€1847):€258.Ô‡XO_XXXÔ€Ô#†XøpXXXO_j#ÔIn€1849€he€qualified€as€a€Member,€RoyalÐ …… ÐCollege€of€Surgeons;€òòMedical€Directoryóó€(1853).€ ]Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú2Ú  Ú.Ý  ÝÔ_Ô€The€new€apparatus€was€constructed€by€ð ðMr.€Elphick,€of€Castle„street,€Oxford„street.ðð;Ð   Ðð ðLetter€from€Mr.€J.€Robinson,ðð€òòMTóó€15€(1846):€274.€An€engraving€and€description€appears€inÐ í  Ðñ¾ñòòTreatiseóó,€ñ¾ññ¿ñÔUSCE.,ÔJamesÔCE.,US.,jÔ€Robinson,€òòA€Treatise€on€the€Inhalation€of€the€Vapour€of€Etheróó€(London:€Webster,€1847),Ð Ùì  Ð17„18.€Ô_Ôñ¿ññ¾ñ17„18ñ¾ññÀñ.ñÀñÔ_ÔÔ_ÔñÀñ€ñÀñM.Ô_Ô€Elphick€was€primarily€a€painter€and€glazier,€with€premises€at€28€Castle€Street,€OxfordÐ ÅØ  ÐCircus;€Pigot,€òòDirectory€of€Londonóó€(London:€Pigot€&€Co.,€1839),€141.€Receiving€it€on€Saturday,Ð ±Ä  Ð26€December,€Robinson€tested€it€on€his€servant€before€using€it€successfully€on€two€patients.€HeÐ °  Ðwas€equally€satisfied€with€the€apparatus€in€three€more€extractions,€before€demonstrating€it€toÐ ‰œ ÐSnow€on€the€28th. 6Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú13Ú  Ú.Ý  ÝÔ_Ô€òòLancetóó€1€(1847):€7;€the€first€òòLancetóó€issue€of€1847€devoted€almost€three€pages€toÐ  Ðmaterial€submitted€by€Dr.€Francis€Boott,€including€a€copy€of€a€paper€that€Henry€J.€Bigelow,Ð yy ÐM.D.,€read€at€the€Boston€Society€of€Medical€Improvement€on€9€November€1846€describingÐ ee Ðmixed€outcomes€observed€in€Dr.€Mortonððs€dental€office€and€at€the€Massachusetts€GeneralÐ QQ ÐHospital.€€Boott€also€submittedòòóó€a€brief€account€of€Robinsonððs€first€dental€operation€in€London€onÐ == Ð19€December€and€a€note€he€had€received€from€Robert€Liston€that€Mr.€Squireððs€ether€inhaler€hadÐ )) Ðworked€well€in€two€surgical€operations. ÆÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú42Ú  Ú.Ý  ÝÔ_Ô€ð ðOperations€without€Pain.€St.€Georgeððs€Hospital,ðð€òòLanceóót€1€(20€February€1847):€210.€€ æÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú19Ú  Ú.Ý  ÝÔ_Ô€Andrew€Ure,€ð ðNew€experimental€researches€on€some€of€the€leading€doctrines€ofÐ ™)™) Ðcaloric;€particularly€on€the€relation€between€the€elasticity,€temperature,€and€latent€heat€ofÐ …*…* Ðdifferent€vapours;€and€on€thermometric€admeasurement€and€capacity,ðð€òòPhilosophicalÐ q+q+ ÐTransactions€of€the€Royal€Society€of€Londonóó€108€(1818):€338„94. ¡Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú21Ú  Ú.Ý  ÝÔ_Ô€ð ðWestminster€Medical€Society,ðð€òòLancetóó€1€(1847):€99. ìÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú23Ú  Ú.Ý  ÝÔ_Ô€ð ðSurgical€Operations€with€the€Vapour€of€Ether€at€St.€Georgeððs€Hospital,ðð€òòLMGóó€39€(22Ð á á  ÐJanuary€1847):€168. Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú20Ú  Ú.Ý  ÝÔ_Ô€The€formula€was€as€follows:€since€the€elastic€force€of€ether€is€30€inches€of€mercury€at€Ð .. Ðits€boiling€point€of€104ð$ð€Fahrenheit,€to€find€the€elastic€force€at€10ð$ð€below€the€boiling€point,€divideÐ ý.ý.  Ð30€by€1.22;€at€20ð$ðF€below€the€boiling€point,€divide€that€quotient€by€1.23;€etc.,€increasing€theÐ í Ðdivisor€by€0.01€for€each€interval€of€10ð$ðF€below€the€boiling€point;€Ure,€350. ëÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú24Ú  Ú.Ý  ÝÔ_Ô€ð ðWestminster€Medical€Society,ðð€òòLMGóó€39€(22€January€1847):€156;€òòLancetóó€1€(23Ð  ÐJanuary€1847):€99.òòóó qÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú27Ú  Ú.Ý  ÝÔ_Ô€H.€Charles€Johnson,€assistant€surgeon€at€St.€Georgeððs€Hospital,€was€a€Fellow€of€theÐ %% ÐWestminster€Medical€Society€and€could€have€seen€Snow€demonstrate€his€apparatus€on€the€16òòthóóÐ  Ðand€recommended€him€to€the€hospital€governors.€ ÄÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú28Ú  Ú.Ý  ÝÔ_Ô€ð ðOperations€without€Pain.€St.€Georgeððs€Hospital,ðð€òòLanceóót€1€(6€February€1847):€158.€ ­Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú29Ú  Ú.Ý  ÝÔ_Ô€ð ðWestminster€Medical€Society,ðð€òòLancetóó€1€(30€January€1847):€121. ÄÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú30Ú  Ú.Ý  ÝÔ_Ô€ð ðOperations€without€Pain.€St.€Georgeððs€Hospital,ðð€òòLanceóót€1€(6€February€1847):€158.€ gÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú31Ú  Ú.Ý  ÝÔ_Ô€Ibid. gÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú32Ú  Ú.Ý  ÝÔ_Ô€Ibid. d Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú33Ú  Ú.Ý  ÝÔ_Ô€ð ðOrder€of€attendance€on€lectures€.€.€.€to€pass€both€the€Hall€and€the€College,ððòò€Lancetóó€1Ð 5%5% Ð(1837„38):€6;€Vinten„Johansen,€et€al.,€òòCholera,€Chloroform,€and€the€Science€of€Medicine:€A€LifeÐ !&!& Ðof€John€Snowóó€(New€York:€Oxford€University€Press,€2003),€30. ¸Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú34Ú  Ú.Ý  ÝÔ_Ô€Snow,€ð ðArsenic€as€a€preservative€of€dead€bodies,ðð€òòLancetóó€1€(1838„39):€264. ŠÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú35Ú  Ú.Ý  ÝÔ_Ô€At€the€16€December€1837€meeting,€ð ðMr.€Josh.€Toynbee,€and€Mr.€Snow,€hadÐ u*u* Ðconducted€a€series€of€experiments€on€these€candles,€to€ascertain€the€effects€of€their€combustionÐ a+a+ Ðon€animal€life.€They€found€that€guinea„pigs,€exposed€to€a€constant€stream€of€vapour,€from€six€ofÐ M,M, Ðthese€candles€[stearin],€for€two€separate€periods€of€eight€hours€each,€were€not€at€all€affected,€evenÐ 9-9- Ðthough€the€temperature€of€the€box,€through€which€the€vapour€passed,€was€occasionally€as€high€asÐ %.%. Ð110ð$ð.€The€animals€ate€their€food,€which€was€constantly€exposed€to€the€gas.€The€experiments€wereÐ //  Ðsubsequently€repeated,€and€carried€on€for€a€period€of€six€days,€in€a€temperature€never€exceedingÐ í Ð80ð$ð,€with€the€same€results.€Two€candles€were€then€made,€each€contained€a€drachm€of€arseniousÐ Ùì Ðacid;€the€vapour€from€these€did€not€affect€the€guinea€pigs.€Subsequent€experiments€with€someÐ ÅØ Ðbirds€had€been€instituted,€but€owing€to€the€apparatus€having€ignited,€no€satisfactory€conclusionÐ ±Ä Ðcould€be€drawn€from€them;€for,€though€one€of€the€birds€perished€in€the€smoke€caused€by€the€fire,Ð ° Ðthe€other€lived€for€four€hours,€after€drinking€with€great€avidity€during€that€time.€The€stomach,€andÐ ‰ œ Ðcommencement€of€the€intestinal€tube€in€each€of€these€birds,€were€found€of€a€bright€red€colourðð;Ð u ˆ Ðð ðWestminster€Medical€Society,ðð€òòLancetóó€1€(1837„38):€463. !Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú36Ú  Ú.Ý  ÝÔ_Ô€Snow,€ð ðOn€the€pathological€effects€of€atmospheres€vitiated€by€carbonic€acid€gas,€andÐ    Ðby€a€diminution€of€the€due€proportion€of€oxygen,€òòEdinburgh€Medical€and€Surgical€Journalóó€65Ð  Ð(1846):€56.€An€example€of€Snowððs€modus€operandi:€ð ðòòFirst€Experiment.óó„„€Into€a€large€glassÐ íí Ðvessel,€containing€2000€cubic€inches€of€atmospheric€air,€inverted€over€water,€70€cubic€inches€ofÐ ÙÙ Ðnitric€oxide€gas€were€passed,€which,€combining€with€part€of€the€oxygen€of€the€air,€formed€nitrousÐ ÅÅ Ðand€nitric€acid,€which€were€absorbed€by€the€water.€After€the€entire€absorption€of€these€acids,€andÐ ±± Ðthe€volume€of€the€air€had€been€restored€to€2000€cubic€inches,€the€composition€of€this€factitiousÐ  Ðatmosphere€was€found€to€be€18€ðð€oxygen,€81€ðð€nitrogen€in€every€100€parts,€the€oxygen€beingÐ ‰‰ Ðreduced€2€ðð€per€cent.€Into€this€a€white€mouse€was€introduced,€and€the€small€quantity€of€carbonicÐ uu Ðacid€given€off€from€its€lungs€was€absorbed€by€lime€water.€It€seemed€unaffected,€and€was€takenÐ aa  Ðout€at€the€end€of€five€hoursðð;€Ibid.,€50„51. ³Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú37Ú  Ú.Ý  ÝÔ_Ô€Snow,€ð ðOn€the€inhalation€of€the€vapour€of€ether,ðð€òòLMGóó€39€(1847):€498. TÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú38Ú  Ú.Ý  ÝÔ_Ô€Ô‡XøpXXXÔJohn€F.€W.€Herschel,€òòA€Preliminary€Discourse€on€the€Study€of€Natural€PhilosophyóóÐ µµ Ð(1830;€Chicago:€University€of€Chicago€Press,€1987),€175;€italicsÔ#†XøpXXXøpb#Ô€retained.€Others€have€pointed€toÐ ¡¡ ÐSnowððs€early€scientific€training€and€research€as€reasons€why€he€was€out€of€the€blocks€so€quicklyÐ  Ðin€developing€an€efficient€ether€inhaler.€For€example,€see€David€A.€E.€Shephard,€ð ðJohn€Snow€andÐ yy Ðresearch,ðð€òòCanadian€Journal€of€Anaesthesiaóó€36€(1989):€224„41;€Richard€H.€Ellis,€ð ðThe€inhalers€ofÐ ee ÐDr.€John€Snow:€his€marks€and€his€score,ðð€in€History€of€Anesthesia€Society,€òòProceedingsóó€8bÐ QQ Ð(1990):€81;€Rod€K.€Calverley,€ð ðAn€early€ether€vaporizer€designed€by€John€Snow,ðð€in€The€HistoryÐ == Ðof€Ô_ÔAnesthesiaÔ_Ô,€Third€International€Symposium,€òòProceedingsóó€(Park€Ridge,€IL:€Wood€Library„Ð ) )  ÐMuseum,€1992);€Ô_ÔShephardÔ_Ô,€òòJohn€Snow,€Anaesthetist€to€a€Queen€and€Epidemiologist€to€a€Nation:Ð !! ÐA€Biographyóó€(Cornwall,€P.€E.€I.,€Can.:€York€Point,€1995).€It€is€also€a€theme€in€Ô_ÔVintenÔ_Ô„Ô_ÔJohansenÔ_Ô,Ð ""  Ðet€al.,€òòCholera,€Chloroform,€and€the€Science€of€Medicine:€A€Life€of€John€Snowóó€(New€York:Ð í"í"  ÐOxford€University€Press,€2003). Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú39Ú  Ú.Ý  ÝÔ_Ô€ð ðEtherized€air€from€the€apparatus€was€gradually€let€on,€by€means€of€a€tap,€openingÐ %% Ðtwo€ways,€which€had€been€added€since€the€previous€week,€and€which€Dr.€Snow€said€Mr.Ð y&y& ÐFerguson,€the€instrument€maker,€had€contrivedðð;€ð ðOperations€without€Pain.€St.€GeorgeððsÐ e'e' ÐHospital,ðð€òòLanceóót€1€(13€February€1847):€184.€Rod€K.€Calverleyððs€description€of€the€WoodÐ Q(Q( ÐLibrary„Museumððs€Mark€II€apparatus€indicates€that€the€ð ðtapðð€was€made€of€brass:€ð ða€brassÐ =)=) Ðquadrant€valve€which€could€be€turned€to€allow€the€inspired€Ô_ÔvaporÔ_Ô€to€be€diluted€with€room€airðð;Ð )*)* Ðð ðAn€early€ether€vaporizer€designed€by€John€Snow,ðð€in€The€History€of€Ô_ÔAnesthesiaÔ_Ô,€ThirdÐ ++ ÐInternational€Symposium,€òòProceedingsóó€(Park€Ridge,€IL:€Wood€Library„Museum,€1992),€92. žÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú18Ú  Ú.Ý  ÝÔ_Ô€John€Dalton,€òòA€New€System€of€Chemical€Philosophyóó€vol.€1,€pt.€1€(1808;€reprint,€withÐ  & & Ðan€introduction€by€Alexander€Joseph,€London:€Peter€Owen,€1965).€There€was€nothing€prescientÐ ù&ù& Ðabout€Daltonððs€choice€of€ether;€it€was€simply€a€suitable€volatile€liquid€for€his€purposes.€ FÐ i/i/ c ÐÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú41Ú  Ú.Ý  ÝÔ_Ô€Ibid.€Implied€in€Hawkinsðð€remarks€was€recognition€of€Snowððs€intuition€and€researchÐ í Ðin€developing€the€ether€table,€which€was€essential€for€anyone€who€sought€to€regulate€theÐ Ùì Ðproportion€of€ether€and€atmospheric€air€administered€to€the€patient.€Two€more€medical€journalsÐ ÅØ Ðpublished€this€table€in€the€week€after€Snowððs€first€operations€at€St.€Georgeððs:€ð ðTable€forÐ ±Ä Ðcalculating€the€strength€of€ether€vapour,ðð€òòLMGóó€39€(29€January€1847):€219„220;€ð ðTable€of€theÐ ° ÐQuantity€of€the€Vapour€of€Ether€in€One€Hundred€Cubic€Inches€of€Air,ðð€òòPharJóó€6€(1846„47;€1Ð ‰ œ ÐFebruary€1847):€361. xÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú43Ú  Ú.Ý  ÝÔ_Ô€In€his€case€note€on€this€operation,€Snow€does€not€admit€to€making€an€error.€Instead,€heÐ Ý Ý  Ðwrote€that€the€patientððs€bronchitis€made€her€sensitive€to€the€ether,€resulting€in€coughing€and€aÐ ÉÉ Ðdecision€to€leave€off€the€ether€for€the€duration€of€the€operation;€Snow,€òòOn€the€Inhalation€of€theÐ µµ ÐVapour€of€Ether€in€Surgical€Operationsóó€(London:€Churchill,€1847),€58.€It€is€possible,€of€course,Ð ¡¡ Ðthat€the€òòLancetóó€reporterððs€observation€was€incorrect.€The€reporter€for€òòLMGóó€accepted€JohnsonððsÐ  Ðexplanation€that€the€ether€was€discontinued€because€of€the€bronchitis;€ð ðWestminster€MedicalÐ yy ÐSociety,ðð€òòLMGóó€39€(1847):€384€Ô_ÔftnÔ_Ô. Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú44Ú  Ú.Ý  ÝÔ_Ô€If€one€exempts€variations€in€the€mouthpiece,€Richard€H.€Ellisðð€taxonomy€remainsÐ  Ðaccurate€for€the€Mark€I€prototype€(23€January€1847)€and€the€Mark€II€version,€although€the€date€ofÐ  Ðthe€latter€should€be€4€February€1847€(first€public€demonstration)€rather€than€19€March€(when€anÐ ññ Ðillustration€first€appeared).€See€Ellis,€ð ðThe€inhalers€of€Dr.€John€Snow:€his€marks€and€his€score,ððÐ ÝÝ Ðin€History€of€Anesthesia€Society,€òòProceedingsóó€8b€(1990):€81,€although€this€is€only€an€abstract€ofÐ ÉÉ ÐEllisððs€presentation.€For€the€dates€of€Snowððs€four€ether€inhalers,€see€Rod€K.€Calverley€ð ðAn€earlyÐ µµ Ðether€vaporizer€designed€by€John€Snow,ðð€in€The€History€of€Ô_ÔAnesthesiaÔ_Ô,€Third€InternationalÐ ¡¡ ÐSymposium,€òòProceedingsóó€(Park€Ridge,€IL:€Wood€Library„Museum,€1992),€94. Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú45Ú  Ú.Ý  ÝÔ_Ô€ð ðWestminster€Medical€Society.€Observations€on€the€vapour€of€ether,€and€itsÐ AA Ðapplication€to€prevent€pain€in€surgical€operations,ðð€òòLMGóó€39€(1847):€383„84.€€ NÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú48Ú  Ú.Ý  ÝÔ_Ô€Snow,€ð ðOn€narcotism€by€the€inhalation€of€vapours,ðð€òòóópart€16,€òòLMGóó€47€(11€AprilÐ ©*©* Ð1851):€625;€he€cited€the€minutes€of€the€20€February€1847€meeting€of€the€Westminster€MedicalÐ •+•+ ÐSociety.€ ¡Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú47Ú  Ú.Ý  ÝÔ_Ô€ð ðWestminster€Medical€Society,ðð€€òòLMGóó€39€(1847):€384. UÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú46Ú  Ú.Ý  ÝÔ_Ô€David€Zuck,€ð ðThomas€Graham,ðð€in€òòóóHistory€of€Anaesthesia€Society,€òòProceedingsóó€17Ð áá Ð(1995):€36-42.€On€contemporary€belief€in€the€capillaries€as€the€seat€of€this€metabolic€process,€seeÐ Í Í  ÐJohn€Ô_ÔElliotsonÔ_Ô:€ð ðAs€it€is€now€generally€believed€that€the€oxygen€which€enters€into€the€bloodÐ ¹!¹! Ðcombines€with€the€carbon,€not€in€the€lungs,€but€in€all€the€extreme€vessels,€and€in€them€formsÐ ¥"¥" Ðcarbonic€acid,€the€evolution€of€heat€throughout€the€body€is€thus€at€once€explained€ð!ð€it€is€a€mereÐ ‘#‘# Ðinstance€of€combustion€in€the€extreme€vessels,€the€union€of€carbon€and€oxygen€being€alwaysÐ }$}$ Ðattended€by€an€increase€in€temperatureðð;€òòHuman€Physiologyóó,€5òòthóó€ed.€(London:€Ô_ÔLongmanÔ_Ô,€1840),Ð i%i% Ð238.€Approximately€three€decades€later,€it€was€demonstrated€that€the€process€took€place€in€theÐ U&U& Ðcells. zÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú52Ú  Ú.Ý  ÝÔ_Ô€ð ðWestminster€Medical€Society,ðð€€òòLMGóó€39€(1847):€385.€Snowððs€subsequentÐ ¥¥ Ðresearches,€as€detailed€in€ð ðOn€Narcotism,ðð€only€solidified€his€attachment€to€this€analogicalÐ ‘‘ Ðhypothesis:€ð ðThe€diminution€of€the€amount€of€carbonic€acid€formed€in€the€system€under€theÐ }} Ðinfluence€of€chloroform,€ether,€and€alcohol,€taken€in€conjunction€with€a€circumstance€shown€in€aÐ ii Ðformer€paper,€that€the€chloroform€and€ether€are€exhaled€unchanged€from€the€blood,€assist€toÐ UU Ðprove€a€view€of€their€modus€operandi€which€I€suggested€with€respect€to€ether,€early€in€1847€[noteÐ AA Ðciting€òòLMGóó€39€(1847):€383].€That€view€may€be€stated€as€follows.Ð -- Ðà  àChloroform,€ether,€and€similar€substances,€when€present€in€the€blood€in€certain€quantities,Ð  Ðhave€the€effect€of€limiting€those€combinations€between€the€oxygen€of€the€arterial€blood€and€theÐ  Ðtissues€of€the€body€which€are€essential€to€sensation,€volition,€and,€in€short,€all€the€animalÐ ññ  Ðfunctions.€The€substances€modify,€and€in€larger€quantities€arrest,€the€animal€functions,€in€theÐ ÝÝ  Ðsame€way,€and€by€the€same€power,€that€they€modify€and€arrest€combustion,€the€slow€oxidation€ofÐ ÉÉ  Ðphosphorus,€and€other€kinds€of€oxidation€unconnected€with€the€living€body,€when€they€are€mixedÐ µµ  Ðin€certain€quantities€with€the€atmospheric€airðð;€òòLMGóó€47€(11€April€1851):€626. ™Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú51Ú  Ú.Ý  ÝÔ_Ô€Ibid.,€part€15,€òòLMGóó€46€(1€November€1850):€749„50. ·Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú56Ú  Ú.Ý  ÝÔ_Ô€Snow,€ð ðÔ_ÔIVEÔ_Ô,ðð€òòLMGóó€39€(19€March€1847):€500. iÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú53Ú  Ú.Ý  ÝÔ_Ô€€ð ðWestminster€Medical€Society,ðð€€òòLMGóó€39€(1847):€384.€The€discussion€on€the€20òòthóóÐ UU Ðincluded€the€earliest€mention€we€have€found€of€what€later€was€termed€the€a€la€Ô_ÔreineÔ_Ô€method:€ð ðMr.Ð AA ÐNorman€had€seen€the€ether€exhibited€to€an€infant€eight€months€old€.€.€.€.€It€was€administered€byÐ -- Ðsprinkling€a€little€ether€on€a€handkerchief,€and€holding€it€before€the€mouth€and€nose€of€the€littleÐ  Ðpatient.ðð ¦Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú57Ú  Ú.Ý  ÝÔ_Ô€ð ðSt.€Georgeððs€Hospital,ðð€òòLMGóó€39€(12€March€1847):€482. ªÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú59Ú  Ú.Ý  ÝÔ_Ô€ð ðWestminster€Medical€Society,ðð€òòLancetóó€1€(6€March€1847):€259. ·Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú61Ú  Ú.Ý  ÝÔ_Ô€ð ðApparatus€for€inhaling€ether,ðð€òòPharJóó€6€(1846„47;€1€March€1847):€423„24.€ áÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú62Ú  Ú.Ý  ÝÔ_Ô€ð ðTo€the€editor€of€the€òòPharmaceutical€Journalóó,ðð€òòPharJóó€6€(1846„47;€1€April€1847):€474„Ð éé Ð75.€ ÀÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú63Ú  Ú.Ý  ÝÔ_Ô€ð ðOperations€without€pain.€St.€Georgeððs€Hospital,ðð€òòLancetóó€1€(3€April€1847):€368. gÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú60Ú  Ú.Ý  ÝÔ_Ô€Ibid. ·Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú65Ú  Ú.Ý  ÝÔ_Ô€Snow,€ð ðÔ_ÔIVEÔ_Ô,ðð€òòLMGóó€39€(19€March€1847):€498. Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú66Ú  Ú.Ý  ÝÔ_Ô€ð ðThe€table€you€honoured€me€by€publishing€in€the€February€number,€is€correct€forÐ U'U' Ðether,€which€is€not€free€from€alcohol,€and€boils€at€104ð$ð.€To€make€it€correct€for€washed€ether,Ð A(A( Ðwhich€boils€at€100ð$ð€four€degrees€must€be€deducted;€for€instance,€for€40ð$ð€read€36ð$ð,€and€so€on€[forÐ -)-) Ðexample,€the€53.6%€ether€vapor€listed€for€74ð$ðF€is€correct€for€70ð$ðF],€and€for€washed€etherÐ ** Ðdeprived€of€its€water€by€potash,€and€boiling€at€98ð$ð,€six€degrees€must€be€deductedðð;€ð ðTo€the€editorÐ ++ Ðof€the€òòPharmaceutical€Journalóó,ðð€òòPharJóó€6€(1€April€1847):€474„75.€ Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú67Ú  Ú.Ý  ÝÔ_Ô€In€a€footnote,€Snow€wrote€ð ðSince€the€above€was€written,€I€have€used€these€large€tubes,Ð ¥-¥- Ðand€found€them€to€answer€my€expectationsðð;€ð ðÔ_ÔIVEÔ_Ô,ðð€541.€He€first€used€the€modified€apparatus€inÐ ‘.‘.  Ðoperations€at€St.€Georgeððs€on€18€March;€€ð ðOperations€without€pain.€St.€Georgeððs€Hospital,ððÐ í ÐòòLancetóó€1€(3€April€1847):€368. nÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú64Ú  Ú.Ý  ÝÔ_Ô€Internal€evidence€makes€it€possible€to€establish€that€Snow€probably€submitted€hisÐ = =  Ðmanuscript€sometime€in€the€period€4„10€March.€He€wrote€(ð ðÔ_ÔIVEÔ_Ô,ðð€540)€that€he€had€administeredÐ )!)! Ðether€in€thirteen€surgical€operations€at€St.€Georgeððs€Hospital;€the€thirteenth€occurred€on€4€March.Ð "" ÐHis€fourteenth€and€fifteenth€were€on€11€March;€Snow,€òòOn€the€Inhalation€of€the€Vapour€of€EtherÐ ## Ðin€Surgical€Operationsóó,€60.€ aÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú11Ú  Ú.Ý  ÝÔ_Ô€Merrington€stated€that€ð ðan€assistant€of€[William]€Morton€came€over€to€this€countryÐ í-) Ðand€on€the€11th€November€[1846]€demonstrated€the€anaesthetic€properties€of€ether€at€a€meetingÐ Ù.ì)  Ðof€the€Medico„Chirurgical€Society€in€Londonðð;€William€R.€Merrington,€òòUniversity€CollegeÐ í ÐHospital€and€its€Medical€School:€A€Historyóó€(London:€Heinemann,€1976),€31.€If€correct,€then€it€isÐ Ùì Ðpossible€that€Snow,€a€Fellow€since€1843,€was€in€attendance.€However,€published€minutes€fromÐ ÅØ Ðthat€meeting€make€no€mention€of€such€a€demonstration;€òòMTóó€15€(1846„47):€184„85.€òòMedico„Ð ±Ä ÐChirurgical€Transactionsóó€29€(1846)€contain€no€record€of€such€an€event,€either. Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú25Ú  Ú.Ý  ÝÔ_Ô€ð ðTable,ðð€òòMTóó€15€(1846„47;€23€January€1847):€325. ŽÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú54Ú  Ú.Ý  ÝÔ_Ô€See€Calverley,€ð ðAn€early€ether€vaporizer,ðð€97.€Tracyððs€apparatus€included€ð ðan€elasticÐ ¹!¹! Ðtube€.€.€.€of€16€inches€in€length,€which€is€surmounted€by€a€double„valved€mouthpiece€of€theÐ ¥"¥" Ðdescription€in€ordinary€use,€a€steel€compress,€padded,€being€used€for€securing€the€nostrils.€It€hasÐ ‘#‘# Ðbeen€hinted€to€me€that€a€valve€made€of€some€fine€tissue,€and€secured€to€the€top€of€the€mouth„cap,Ð }$}$ Ðwould€be€an€improvement€on€the€compress€in€general€use,€as€many€patients€dislike€their€nosesÐ i%i% Ðbeing€secured€by€such€an€instrumentðð;€S.€J.€Tracy,€Ô‡&öc%XXÔð ðApparatus€for€the€Respiration€of€Ether€Vapour,ððÐ U&U& ÐòòLMGóó€39€(22€January€1847):€167.Ô#†XøpX%&öcÝ#Ô 3Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú55Ú  Ú.Ý  ÝÔ_Ô€ð ðIn€administering€the€vapour€of€ether€to€a€patient€in€the€recumbent€position,€it€wasÐ á(á( Ðfound€the€valves€would€not€act€until€the€patientððs€head€was€raised€and€the€valve„piece€becameÐ Í)Í) Ðperpendicular.€To€remedy€this,€I€have€secured€the€end€of€an€elastic€tube€2€inches€in€length€intoÐ ¹*¹* Ðthe€valve„piece,€which€terminates€in€a€mount,€on€which€is€placed€a€pad€with€a€hole€in€the€centreÐ ¥+¥+ Ðformed€of€10€or€12€thicknesses€of€flannel€and€covered€with€morocco,€somewhat€of€an€oval€shape,Ð ‘,‘, Ðbeing€5ðð€inches€in€its€long€and€4€inches€in€its€short€diameter.€A€mouth„piece€of€ivory€or€silver,Ð }-}- Ðan€inch€in€length€from€the€worm,€with€a€good„sized€bore€and€pierced€by€several€transverse€holes,Ð i.i.  Ðis€screwed€into€the€mount,€over€which€a€piece€of€vulcanized€rubber€larger€than€the€pad€with€aÐ í Ðhole€in€its€centre€is€placed.€The€person€who€administers€the€vapour€can€easily€press€this€on€theÐ Ùì Ðpatientððs€mouth,€and€compress€the€nose€with€the€sameðð;€S.€J.€Tracy,€ð ðThe€use€of€ether€vapour€inÐ ÅØ Ðsurgical€operations,ðð€òòLMGóó€39€(5€February€1847):€258. gÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú16Ú  Ú.Ý  ÝÔ_Ô€Ibid. !Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú17Ú  Ú.Ý  ÝÔ_Ô€John€Snow,€ð ðOn€the€inhalation€of€the€vapour€of€ether,ðð€òòLMGóó€39€(1847):€500,€499;Ð m#m# Ðhereafter€cited€parenthetically€as€ð ðÔ_ÔIVEÔ_Ô.ðð °Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú58Ú  Ú.Ý  ÝÔ_Ô€Standard€field€guides,€such€as€Ô_ÔLarsÔ_Ô€Ô_ÔJonssonÔ_Ôððs€òòBirds€of€Europeóó€(Princeton,€NJ:Ð Í Í  ÐPrinceton€University€Press,€1993),€do€not€list€a€green€linnet.€Neither€does€John€Gould,€€òòThe€BirdsÐ ¹ ¹  Ðof€Great€Britainóó€(1873).€We€thank€Betty€Vinten„Johansen€for€resolving€this€little€mystery€byÐ ¥¥ Ðconsulting€T.€H.€Nelson,€òòThe€Birds€of€Yorkshireóó,€vol.€1€(London:€A.€Brown€&€Sons,€1907).€ForÐ ‘‘ Ðthe€Ô_ÔGreenfinchÔ_Ô€(formerlyòò€Ô_ÔLigurinusÔ_Ô€chlorisóó,€currently€òòCarduelis€chlorisóó):€ð ðOf€local€names,€GreenÐ }} ÐLinnet€and€Green€Lenny€are€generalðð€(165).€With€respect€to€the€Linnet€(òòÔ_ÔLinotaÔ_Ô€cannabinaóó,Ð ii Ðcurrently€òòCarduelis€cannabinaóó):€In€the€autumn,€ð ðthey€often€remain€for€some€time€on€the€sand„Ð UU Ðdunes€and€waste€lands€near€the€coast,€afterwards€resorting€to€the€stubbles€where€they€feed€inÐ AA Ðcompany€with€Ô_ÔGreenfinchesÔ_Ô€and€other€small€birds,€and€it€is€at€these€times€that€large€numbers€fallÐ -- Ðvictims€to€the€snares€of€the€bird„catchersðð€(186).€Among€local€names€for€Linnet€was€Red€Linnet. ùÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú50Ú  Ú.Ý  ÝÔ_Ô€Another€method€would€have€been€to€use€a€manometer€to€measure€the€volume€changeÐ yy Ðin€a€closed€container€while€absorbing€the€CO2€in€lime€water.€Under€Ô_ÔetherizationÔ_Ô,€less€oxygenÐ e e  Ðwould€be€used,€and€less€CO2€put€out,€if€the€metabolism€was€depressed€ð!ð€hence€an€additive€effectÐ Q Q  Ðon€the€readings,€increasing€the€sensitivity. QÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú68Ú  Ú.Ý  ÝÔ_Ô€David€Zuck,€ð ðPhysics€of€heat€and€vaporization:€Its€history€and€application€to€theÐ  Ðdesign€of€anaesthetic€vaporizers,ðð€òòCPD€[Continuous€Professional€Development]€Anaesthesiaóó€1Ð yy Ð(1999):€88„93. Ý ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú22Ú  Ú.Ý  ÝÔ_Ô€David€Zuck,€ð ðJulius€Jeffreys€ð!ð€Pioneer€of€Humidification,ðð€in€History€of€AnaesthesiaÐ A A  ÐSociety,€òòProceedingsóó€8b€(1990):€70„80.€ ”Ð 5.5. c ÐÝ ƒV¿%ÝÔCEUS.,Ôà  àÚ  Ú49Ú  Ú.Ý  ÝÔ_Ô€Snow,€ð ðOn€the€Pathological€Effects€of€Atmospheres€vitiated€by€Carbonic€Acid€Gas,Ð í Ðand€by€a€diminution€of€the€due€proportion€of€Oxygen,ðð€òòEdinburgh€Medical€and€Surgical€JournalóóÐ Ùì Ð65€(1846):€51;€the€quote€is€from€the€fifth€experiment.€Ý ƒö\!ÝÔCEUS.,ÔÝ  ÝÔ_ÔÑ„°ÑÑ9°Ñò òÑ€OaÑ27€March€2005ó óÐ 9 ÐÌà  àà ` àà ¸ àà  àà h àà À àà  àà p àÌÓ  Ó1847€ð!ð€John€Snowððs€òòÔ_ÔannusÔ_Ô€mirabilisóó,€year€of€Ô_ÔconsilienceÔ_ÔÐ ýÄ ÐÓôÓÌÓ  ÓPeter€Ô_ÔVintenÔ_Ô-Ô_ÔJohansenÔ_Ô,€Ô_ÔPh.D.Ô_Ô,€Department€of€History€&€Center€for€Ethics€in€the€Life€Sciences,Ð Õœ ÐMichigan€State€UniversityÐ Áˆ ÐÌandÐ ™ ` ÐÌDavid€Zuck,€Ô_ÔFRCAÔ_Ô,€Ô_ÔDMHSAÔ_ÔÐ q 8  ÐPast€President,€History€of€Anaesthesia€Society€ò ò(Fig.€1Ùƒ!Ù)ó óÐ ] $  ÐÌÌÌÓ  ÓÓÓÓÓPrepared€for€the€12òòthóó€Annual€Spring€Meeting€of€the€Anesthesia€History€Association,€6€„€7€AprilÐ Ø  Ð2005,€Birmingham,€Alabama.Ð ýÄ ÐÌÌÓÈÓÓ  Óà @ àà @` àà @¸ àà @ àà @h à*€*€*Ð Áˆ ÐÓšÓÓÓI€thank€the€Association€for€honoring€our€book,€òòCholera,€Chloroform,€and€the€Science€ofÐ ™` ÐMedicine:€A€Life€of€John€Snowóó,€with€the€David€M.€Little€prize€last€October.€I€bring€youÐ …L Ðgreetings€from€the€rest€of€the€writing€team€ð!ð€Howard€Ô_ÔBrodyÔ_Ô,€Nigel€Ô_ÔPanethÔ_Ô,€Steve€Ô_ÔRachmanÔ_Ô,€MikeÐ q8 ÐRip,€and€David€Zuck.€We€wrote€the€manuscript.€A€team€at€Oxford€University€Press€transformedÐ ]$ Ðit€into€the€book.€Your€award€honors€them€as€well,€particularly€Jeffrey€House,€recently€retiredÐ I Ðeditor€of€the€Medicine€Division,€and€Nancy€Ô_ÔWolitzerÔ_Ô,€who€supervised€every€facet€of€theÐ 5ü Ðproduction€process.€Carrie€Pedersen,€the€new€Medicine€editor€who€is€in€Birmingham€for€this€andÐ !è Ðthe€Ô_ÔAAHMÔ_Ô€conferences,€will€shepherd€the€bookððs€life€from€now€on.Ð  Ô Ðà  àMy€presentation€this€morning€has€its€origins€in€disagreement€within€the€writing€teamÐ ùÀ Ðabout€how€to€structure€the€ether€chapter.€Four€of€us,€including€the€primary€drafter,€SteveÐ å¬ ÐÔ_ÔRachmanÔ_Ô,€preferred€a€thematic€format.€David€Zuck€and€I€believed€a€narrative€would€be€moreРј Ðeffective,€but€we€were€outvoted.€Six€months€ago,€David€and€I€decided€to€begin€writing€such€aÐ ½ „  Ðnarrative€for€publication€as€an€article.€When€Ô_ÔA.J.Ô_Ô€Wright€asked€me€to€deliver€the€opening€plenaryÐ ©!p! Ðlecture,€David€and€I€thought€it€would€be€appropriate€to€distill€a€preparation€from€the€emergingÐ •"\" Ðmanuscript.€Ð #H # ÐÓ ÓÐ  m$4!$ ÐÑOaÑâ âѰ„Ñâ âÑ  ÑØØÑ8€øpXXdìdÈ8ÑÑ€¿[ ÑOn€Monday€morning,€the€28òòthóó€of€December€1846,€John€Snow,€M.D.,€was€among€three€medicalÐ í Ðfriends€who€James€Robinson€ò ò(Fig.€2Ùƒ!Ù)ó ó€had€invited€to€his€home€surgery€in€Gower€Street€ò ò(Fig.€3;Ð ÅØ ÐFig.€4)ó ó,€several€blocks€south€of€University€College€Hospital,€central€London€ò ò(Fig.€5;€ó ócircled).× ƒ ×Ý ƒ$ÓÝòòÚ  Ú1Ú  ÚóóÝ  Ý×  ×ò òó óÐ ¥¸ ÐThe€intention€was€to€demonstrate€the€effectiveness€of€a€new€ether€inhaler€ò ò(Fig.€6)ó ó,€constructedÐ … ˜ Ðaccording€to€his€specifications€by€a€local€medical€instrument€technician.× ƒ# ×Ý ƒ$ÓÝòòÚ  Ú2Ú  ÚóóÝ  Ý×  ×€Robinson€poured€oneÐ e x Ðounce€of€washed€ether€over€a€score€of€small,€triangular€sponge€pieces,€made€certain€that€allÐ =P  Ðpieces€were€moist,€and€placed€them€in€both€the€upper€and€lower€parts€of€his€inhaler,€based€on€aÐ (  ÐNoothððs€glass€apparatus€ò ò(Fig.€7)ó ó,€which€had€been€invented€in€1776€to€make€soda€water€in€theÐ í  Ðhomeò òó ó.€He€inserted€a€double€glass€stopper€into€the€opening€at€the€top€ò ò(Fig.€8)ó ó,€and€covered€it€withÐ Íà Ða€glass€cap.× ƒ ×Ý ƒ$ÓÝòòÚ  Ú3Ú  ÚóóÝ  Ý×  ׀Р­À Ðà  àThe€first€patient€ð!ð€ð ða€young€man,€of€robust€constitution,€and€about€twenty€years€of€ageðð€ð!ðÐ …˜ Ðwas€brought€into€the€room€and€seated€in€a€chair.€Robinson€picked€up€the€mouthpiece,€connectedÐ ]p Ðby€a€flexible€tube€to€the€lower€part€of€the€apparatus€ò ò(Fig.€9)ó ó,€and€told€the€man€to€clasp€his€teethò òó óÐ 5H Ðover€a€protruding€ivory€tube€(arrow)€while€the€pad€(green€oval),€made€of€sheet€copper,€leatherÐ ( Ðand€wool,€was€shaped€to€fit€the€contours€of€his€lower€face.€When€he€was€satisfied€that€noÐ í Ðatmospheric€air€should€seep€past€the€pad€of€the€mouthpiece,€he€removed€it€long€enough€to€insert€aÐ Å Ø Ðclip€over€the€nostrils€ò ò(Fig.€10)ó ó,€remove€the€cap€(light€green€oval)€from€the€top€of€the€apparatus,Ð "°  Ðand€the€inner€stopper€(dark€green€oval),€set€the€stopcock€(blue€square)€in€front€of€the€mouthpieceÐ }$" Ðin€the€open€position,€and€reposition€the€face-pad.€He€told€the€patient€to€inhale,€then€on€exhalationÐ U&h!$ Ðnoted€that€the€horizontal€valve€(green€arrow)€popped€up€as€expired€air€passed€into€the€room;€it,€asÐ -(@#& Ðwell€as€the€vertical€swing€valve€(red€arrow)€preventing€expired€air€from€returning€to€theÐ *%( Ðapparatus,€were€functioning€properly.ò òó ó€According€to€Robinsonððs€case€note,€the€ð ðpatient,€afterÐ Ý+ð&* Ðinhaling€the€vapour€for€about€two€minutes,€became€insensible,€and€the€tooth€was€extracted.€OnÐ µ-È(, Ðrecovering,€he€was€requested€to€give€an€account€of€his€sensations,€but€he€could€neither€recollectÐ í Ðanything,€nor€was€he€aware€when€his€tooth€had€been€taken€out;€.€.€.€he€left€the€surgery€perfectlyÐ ÅØ Ðwell.ðð× ƒ ×Ý ƒ$ÓÝòòÚ  Ú4Ú  ÚóóÝ  Ý×  ×Ð ° Ðà  àThe€next€patient,€a€youth€in€his€late€teens,€was€less€compliant.€Rumors€were€alreadyÐ u ˆ Ðcirculating,€only€a€week€since€Robinsonððs€first€use€of€inhalation€ether€in€Dr.€Francis€BoottððsÐ M ` Ðhome€(ò òFig.€11ó ó),€when€he€had€rendered€Miss€Lonsdale€insensible€before€extracting€a€molar€(ò òFig.Ð %8  Ð12ó ó),€that€this€dentist€ð ðððsent€people€to€sleep€and€then€took€out€the€whole€of€their€teeth.ðððð€The€ladÐ   Ðdid€not€want€himself€readied€for€a€set€of€dentures,€and€he€adamantly€refused€to€let€RobinsonÐ åø  Ðplace€the€mouthpiece€on€his€face.€So€Snow€and€his€two€surgeon€colleagues€watched€as€RobinsonÐ ½Ð Ðò òó óyanked€a€rotten€tooth€the€old-fashioned€way€ð!ð€similar€to€the€dentist€in€this€painting€ò ò(Fig.€13)ó ó€byÐ •¨ ÐTheodor€Rombouts€from€two€centuries€earlier.× ƒ ×Ý ƒ$ÓÝòòÚ  Ú5Ú  ÚóóÝ  Ý×  ×ò òó óÐ uˆ Ðà  àBut€Robinson€had€one€more€patient€waiting€in€the€foyer,€a€girl€ð ðbetween€thirteen€andÐ M` Ðfourteen€years€of€age,€of€a€weakly€and€delicate€constitution.ððò ò€ó óShe€did€not€resist€the€administrationÐ %8 Ðof€ether€vapor,€and€ð ðin€twenty€inspirations€became€perfectly€narcotized.ðð€Although€Robinson€wasÐ  Ðable€to€remove€a€diseased€molar€in€seconds,€it€took€the€girl€four€minutes€to€ð ðrecover€herÐ Ýð Ðfacultiesðð;€she€immediately€ð ðcomplained€of€head-ache€and€oppression.ðð€She€felt€better€afterÐ µ È Ðdrinking€a€glass€of€water,€to€which€a€drop€of€ammonia€had€been€added.× ƒ ×Ý ƒ$ÓÝòòÚ  Ú6Ú  ÚóóÝ  Ý×  ×€Since€ð ðshe€could€give€noÐ "   Ðaccount€of€her€state,€and€was€unaware€when€or€how€the€tooth€had€been€removed,ðð€RobinsonÐ e$x" Ðconsidered€this€operation€a€ð ðmost€perfect€successðð,€even€though€he€had€administered€ð ðmoreÐ =&P!$ Ðvapour€.€.€.€than€necessary.ðð× ƒ ×Ý ƒ$ÓÝòòÚ  Ú7Ú  ÚóóÝ  Ý×  ×Ð ((#& Ðà  àJohn€Snowððs€reactions€to€Robinsonððs€use€of€ether€are€unknown.€He€said€nothing€publiclyÐ í)%( Ðabout€this€new€anesthetic€process€for€nearly€three€weeks.€Then,€on€Saturday€the€16òòthóó€of€January,Ð Å+Ø&* Ð1847,€he€announced€at€a€meeting€of€the€Westminster€Medical€Society€that€he€had€designed€anÐ -°(, Ðinhaler€that€he€believed€was€vastly€superior€to€those€currently€in€use,€including€Robinsonððs.€WhatÐ í Ðhad€happened?Ð ÅØ ÐÓ  Ó*€*€*Ð ° ÐÓK$ÓWe€know€which€medical€journals€and€newspapers€Snow€read€regularly,€so€it€is€very€likely€thatÐ u ˆ Ðbefore€visiting€Robinsonððs€surgery€he€had€seen€the€December€18€issue€of€the€€òòLondon€MedicalÐ M ` ÐGazetteóó€(ò òFig.€14ó óÔUSCE.,Ô)€that€announced€Mortonððs€ð ðdiscoveryðð€of€a€new€anodyne€process.€While€theÐ %8  Ðeditors€noted€that€ð ðany€one€may€put€the€new€process€to€the€test€of€experiment,ðð€ò ò(Fig.€15)ó ó€ð ðsomeÐ   Ðcaution€must€.€.€.€be€observed€in€employing€the€Ô_ÔvapourÔ_Ô€of€ether€in€the€way€suggested.€Ether€is€aÐ åø  Ðstrong€narcotic,€and€its€Ô_ÔvapourÔ_Ô€speedily€produces€complete€lethargy€and€coma:€it€is€exceedinglyÐ ½Ð Ðvolatile€.€.€.€.€In€one€case€it€has€destroyed€life,€and€in€another€caused€apoplexy.€.€.€.€It€must€beÐ •¨ Ðregarded€as€producing€a€state€of€temporary€poisoning€in€which€the€nervous€system€is€mostÐ m€ Ðpowerfully€affected.ðð× ƒ ×Ý ƒ$ÓÝòòÚ  Ú8Ú  ÚóóÝ  Ý×  ×ò òó ó€Snow€had€apparently€never€used€ether€ð ðas€a€mere€frolic,ðð€following€ð ðtheÐ EX Ðold€plan€of€introducing€a€teaspoonful€of€ether€into€a€bladder€or€silk€bag,€and€inhaling€it€in€theÐ 0 Ðsame€manner€as€nitrous€oxide€gas.ðð× ƒ ×Ý ƒ$ÓÝòòÚ  Ú9Ú  ÚóóÝ  Ý×  ×€As€a€clinician,€however,€he€was€quite€familiar€with€ether€asÐ õ Ða€ð ðclass€of€medicines.ðð€He€knew€it€could€be€administered€safely€because€he€had€undertakenÐ Íà Ðexperiments€with€it€and€ð ðother€volatile€medicinesðð€in€1842/43€and€recommended€theirÐ ¥ ¸ Ðtherapeutic€value€for€the€relief€of€respiratory€congestion.€He€also€knew€that€ether€did€not€act€likeÐ }"  Ðtypical€poisons€since€he€had€determined€that€it€was€a€gas€which,€like€carbon€dioxide,€ð ðÔ_Ôescape[dÔ_Ô]Ð U$h" Ðwith€the€breath.ðð× ƒ ×Ý ƒ$ÓÝòòÚ  Ú10Ú  ÚóóÝ  Ý×  ×€So€his€mind€was€hardly€a€blank€slate€when€he€had€observed€RobinsonÐ -&@!$ Ðadminister€ether€at€the€end€of€December€1846.× ƒ‰ ×Ý ƒ$ÓÝòòÚ  Ú11Ú  ÚóóÝ  Ý×  ×Ð (#& Ðà  à€During€the€first€ten€days€of€the€new€year,€the€medical€journals€reported€inconsistentÐ Ý)ð$( Ðresults€from€the€inhalation€of€sulphuric€ether,€so„called€because€it€was€prepared€by€reacting€ethylÐ µ+È&* Ðalcohol€with€sulphuric€acidÔCE.,US.,%Ô.€New€Yearððs€day€issues€of€the€òòLondon€Medical€Gazetteóó€and€theÐ - (, ÐòòPharmaceutical€Journalóó€described€two€operations€on€the€21òòstóó€of€December€by€òòóóRobert€Liston,Ð í Ðsurgeon€at€University€College€Hospital,€in€which€both€patients€were€successfully€renderedÐ ÅØ Ðinsensible€by€ð ðan€ingenious€apparatus€.€.€.€contrived€by€Mr.€Squire,€of€Oxford€Streetðð€ò ò(Fig.€16)ó ó.× ƒ ×Ý ƒ$ÓÝòòÚ  Ú12Ú  ÚóóÝ  Ý×  ×Ð ° ÐOn€2€January,€the€òòLancetóó€published€accounts€originating€from€Boston€in€which€patients€awoke€inÐ }  Ðthe€midst€of€the€operation,€ò òó óeven€after€inhaling€ether€for€as€long€as€eight€minutes€before€theÐ U h Ðprocedure€began.€While€there€were€no€reports€of€any€fatalities,€there€had€been€cases€where€theÐ -@  Ðpulse€plummeted,€or€a€lethargic€state€continued€for€as€much€as€an€hour.× ƒ% ×Ý ƒ$ÓÝòòÚ  Ú13Ú  ÚóóÝ  Ý×  ×€Under€the€headline,Ð   Ðð ðpainless€surgical€operations,ðð€the€January€2òòndóó€issue€of€òòMedical€Timesóó€noted€that€Robinson€hadÐ Ýð  Ðtested€Mortonððs€ð ðinventionðð€by€means€of€what€the€editors€considered€ð ðan€elegant€apparatus.ðð× ƒ ×Ý ƒ$ÓÝòòÚ  Ú14Ú  ÚóóÝ  Ý×  ×Ð µÈ Ðà  àThe€9€January€issue€of€the€òòMedical€Timesóó€contained€a€wood€engraving€(ò òFig.€17ó ó)€ofÐ   ÐRobinsonððs€original€inhaler€and€an€effusive€editorial€endorsement,€asserting€that€it€best€fulfilledÐ m€ Ðall€their€requirements€for€the€successful€administration€of€ð ðthe€ethereal€vapour.ðð× ƒ ×Ý ƒ$ÓÝòòÚ  Ú15Ú  ÚóóÝ  Ý×  ×€By€then€it€wasÐ EX Ðalready€outdated€by€the€new€inhaler€Robinson€had€used€in€Snowððs€presence.€The€editors€alsoÐ 0 Ðendorsed€the€original€Robinson€inhaler€by€counter„examples:€At€University€College€HospitalÐ õ Ðeight€days€earlier,€Squireððs€apparatus€ò ò(Fig.€18)ó ó€had€failed€ð ðto€produce€insensibilityðð€in€a€patient,Ð Íà Ðwhile€Liston€cooled€his€heels€for€ten€minutes€before€deciding€to€amputate€ð ðwith€the€usual€amountÐ ­ À Ðof€pain.ðð€Squireððs€apparatus€worked€no€better€the€following€day€for€a€different€surgeon,€nor€againÐ …"˜  Ðfor€Liston€two€days€later€ð!ð€even€though,€this€time,€he€waited€twenty€minutes.€But€then€ð ða€mostÐ ]$p" Ðextraordinary€scene€occurred,ðð€according€to€the€editorial.€In€the€next€operation,€ð ðMr.€RobinsonÐ 5&H!$ Ðsuperintended€the€inhalation€of€the€vapour,€using€his€own€apparatus;€[ò ò(Fig.€19)ó ó]€the€patientÐ  ( #& Ðbecame€perfectly€insensible€in€two€minutes,€and€the€operation€was€completed€before€the€patientÐ í)%( Ðwas€aware€that€it€had€commenced.ðð× ƒ· ×Ý ƒ$ÓÝòòÚ  Ú16Ú  ÚóóÝ  Ý×  ×Ð Å+Ø&* ÐÐ -°(, ÐÓ  Ó*€*€*€Ð í ÐÓ';ÓBut€Snow€ò ò(Fig.€20)ó ó€had€not€jumped€on€the€Robinson€bandwagon.€During€the€fortnight€afterÐ ÅØ Ðobserving€the€dentist€use€his€second€inhaler,€Snow€had€confirmed€a€suspicion€ð!ð€that€theÐ ¥¸ Ðinconsistent€results€he€observed€in€Robinsonððs€surgery€and€read€about€in€the€medical€journalsÐ }  Ðwere€caused€by€variations€in€the€temperature€of€the€air€passing€through€glass€inhalers€such€as€theÐ U h Ðmodified€Noothððs€apparatus€Robinson€was€using.ò òó ó€Snow€had€secured€a€glass€vessel,€insertedÐ -@  Ðsponges€soaked€with€ether,€and€using€ð ða€delicate€thermometer,ðð€noted€that€the€air€ð ðleaves€theÐ   Ðapparatus€many€degrees€colder€than€it€entered.ððÔ_Ô× ƒ¸ ×Ý ƒ$ÓÝòòÚ  Ú17Ú  ÚóóÝ  Ý×  ×Ô_Ô€As€a€physician€who€was€also€an€expert€chemist,Ð Ýð  Ðit€is€likely€that€he€knew€from€prior€study€and€experimentation€that€liquid€ether€exerted€a€coolingÐ µÈ Ðeffect€on€ambient€air€and€that€the€elastic€force€(saturated€Ô_ÔvaporÔ_Ô€pressure€ð!ð€Ô_ÔSVPÔ_Ô)€of€volatileÐ   Ðliquids€such€as€ether€was€temperature„dependent.€He€wrote€a€few€months€later€ò ò(Fig.€21)ó ó€that€itÐ ex Ðð ðoccurred€to€my€mind€that€by€regulating€the€temperature€of€the€air€whilst€it€is€exposed€to€theÐ EX Ðether,€we€should€have€the€means€of€ascertaining€and€adjusting€the€quantity€of€vapour€that€will€beÐ 0 Ðcontained€in€itðð€(ð ðÔ_ÔIVEÔ_Ô,ðð€498).€The€striking€fact€is€that€whereas€Robinson€and€other€proto„Ð õ ÐÔ_ÔanesthetistsÔ_Ô€attempted€to€resolve€problems€with€the€new€process€only€by€empirical€tinkering€withÐ Íà Ðtheir€inhalers€and€mouthpieces,€Snowððs€initial€approach€was€totally€different.€Ð ¥ ¸ Ðà  àHe€looked€to€chemistry€and€physics€for€verification€of€his€hypothesis€that€the€amount€ofÐ }"  Ðether€inhaled€depended€on€temperature.€He€was€aware€that€ð ðthe€elastic€force€of€the€vapour€ofÐ U$h" Ðether€has€been€investigated€by€Dalton,€and€later€by€Ureðð€(ð ðÔ_ÔIVEÔ_Ô,ðð€498).€Around€1805,€arising€fromÐ -&@!$ Ðhis€meteorological€studies€into€rainfall,€Dalton€had€formulated€the€concept€of€elastic€force.€TheÐ (#& ÐòòNew€System€of€Chemical€Philosophyóó€that€he€published€a€few€years€later€contained€Ô_ÔSVPÔ_Ô€tablesÐ Ý)ð$( Ð(ò òFig.€22ó ó)€over€a€range€of€temperatures€for€various€volatile€liquids,€including€ether.× ƒk ×Ý ƒ$ÓÝòòÚ  Ú18Ú  ÚóóÝ  Ý×  ×€TheÐ µ+È&* Ðphysician€and€pioneer€of€chemistry,€Andrew€Ure,€recalculated€Daltonððs€tables€in€a€search€forÐ •-¨(, Ðgreater€accuracy,€and€published€his€results€in€an€1818€essay€on€ð ðDoctrines€of€Caloric.ðð× ƒ- ×Ý ƒ$ÓÝòòÚ  Ú19Ú  ÚóóÝ  Ý×  ×€WithÐ í Ðrespect€to€ether,€Ure€proposed€a€set€of€ratios€(ò òFig.€23ó ó)€for€the€elastic€force€that€accorded€closelyÐ ÅØ Ðwith€actual€measurements€he€conducted€over€mercury,€using€a€manometer€of€his€own€devisingÐ ¥¸ Ðò ò(Fig.€24)ó ó.× ƒ6 ×Ý ƒ$ÓÝòòÚ  Ú20Ú  ÚóóÝ  Ý×  ׀Р}  Ðà  àIf€Ureððs€table€was€accurate,€Snow€could€save€himself€a€lot€of€work.€He€bent€a€longÐ ] p Ðgraduated€tube€until€it€approximated€the€form€of€Ureððs€instrument€ò ò(Fig.€25)ó ó€(ð ðÔ_ÔIVEÔ_Ô,ðð€498„99).ò òó óÐ 5H  ÐThen,€he€immersed€the€tube€in€a€tall€glass€jar€containing€water€at€a€temperature€of€44ð$ðF,€makingÐ (  Ðcertain€that€the€sealed€leg€was€completely€covered€by€the€water.€He€added€mercury,€passed€airÐ í  Ðinto€the€sealed€leg,€made€certain€the€mercury€was€at€the€same€level€in€both€legs,€and€noted€theÐ ÅØ Ðdistance€between€the€level€of€mercury€and€the€top€of€the€sealed€leg€(for€example,€one€inch€in€theÐ ° Ðgraduated€tube€on€the€left€in€the€figure).€Nextò òó ó,€he€carefully€inserted€a€long€tube€into€the€open€leg,Ð uˆ Ðwithdrew€most€of€the€mercury,€added€a€few€drops€of€unwashed€sulphuric€ether€ð!ð€an€accurateÐ M` Ðchoice€for€replicating€Ureððs€experiments,€but€it€would€become€an€embarrassing€oversight€later€ð!ðÐ %8 Ðtipped€the€jar€and€instrument€a€little,€and€breathed€gently€through€the€tube€until€the€ether€passedÐ ý Ðthrough€the€mercury€and€mixed€with€the€air€in€the€sealed€leg.€Snow€righted€the€instrument,€addedÐ Õè Ðmercury€until€the€two€legs€were€equilibrated,€and€re„measured€the€level€in€the€sealed€leg€ð!ð€nowÐ ­ À Ð1.370€inchesò ò€ó ó(in€the€graduated€tube€on€the€right€in€the€figure).ò òó ó€He€then€divided€the€originalÐ …"˜  Ðvolume€by€the€new€measurement€to€determine€the€percentages€of€air€and€ether€Ô_ÔvaporÔ_Ô€ò ò(Fig.€26)ó ó:Ð e$x" ÐÓ  Óà @ àà @` à€1€ðð€1.370€=€73%€air,€Ð E&X!$ ÐÓïOÓwith€the€difference€of€27%€being€the€amount€of€ether€Ô_ÔvaporÔ_Ô€at€that€temperature.€Using€DaltonððsÐ (0#& ÐLaw€of€Partial€Pressures,€a€quick€calculation:€0.27€x€30€(standard€barometric€pressure)€=€8.1€forÐ õ)%( Ðthe€elastic€force,€which€was€identical€with€Ureððs€figure€for€44ð$ðF€ò ò(Fig.€Ô_Ô27).ó óÔ_Ô€Successively,€SnowÐ Í+à&* Ðrepeated€this€process€in€10ð$ð€increments€between€44ð$ð€and€84ð$ð.€When€these€results€also€agreedÐ ­-À(, Ðwith€Ureððs€table,€he€found€that€he€had€confirmed€the€first€part€of€his€hypothesis:€the€amount€ofÐ í Ðsaturated€ether€Ô_ÔvaporÔ_Ô€in€air€increased€with€temperature€ð!ð€doubled,€in€fact,€between€44ð$ðF€andÐ ÅØ Ð74ð$ðF.× ƒ0 ×Ý ƒ$ÓÝòòÚ  Ú21Ú  ÚóóÝ  Ý×  ×€His€findings€meant€that€if€the€ambient€temperature€of€a€room€was€low,€glass€inhalersÐ ° Ðyielded€very€little€ether€Ô_ÔvaporÔ_Ô.€Then,€during€the€second€week€of€January,€Snow€used€UreððsÐ u ˆ Ðformula€to€create€a€more€refined€table€ò ò(Fig.€28)ó ó€of€the€ð ðstrength€of€ether€vapourðð€in€100€cubicÐ M ` Ðinches€of€air€at€two„degree€temperature€intervals.€He€added€columns€on€weights€for€each€intervalÐ -@  Ðò ò,ó ó€using€standard€formulas€ò ò(Fig.€29)ó ó€that€1€cubic€inch€of€ether€yields€0.787€grains€of€liquid€ether,Ð   Ðand€that€1€cubic€inch€of€air€weighs€0.30€grains€(ð ðÔ_ÔIVEÔ_Ô,ðð€498).€He€submitted€this€table€to€threeÐ åø  Ðmedical€journals€for€publication.€Ð ½Ð Ðà  àNext€he€began€to€design€an€apparatus€that€would€permit€him€to€control€the€temperature€ofÐ •¨ Ðthe€air€that€a€patient€would€inhale.ò òó ó€Metals€and€water€were€good€conductors€of€heat.€The€trick€wasÐ m€ Ðto€construct€an€apparatus€using€both€conductors€that€permitted€an€operator€to€regulate€the€Ð EX Ðtemperature€of€ether€Ô_ÔvaporÔ_Ô€and€air€passing€though€it€without€obstructing€the€patientððs€breathing.€ItÐ 0 Ðoccurred€to€Snow€that€an€apparatus€constructed€partially€on€the€principle€of€the€JeffreysÐ õ Ðhumidifier€ò ò(Fig.€30)ó ó,€which€he€had€used€in€his€practice€since€1842,€might€meet€his€expectationsÐ Íà Ð(ð ðÔ_ÔIVEÔ_Ô,ðð€500).× ƒÉ ×Ý ƒ$ÓÝòòÚ  Ú22Ú  ÚóóÝ  Ý×  ×€His€design€would€replace€Jeffreysðð€saucepan€by€a€round€tin€box;€solder€the€tinÐ ­ À Ðvolute€to€the€inside€of€the€lid,€and€provide€an€opening€in€the€Ô_ÔcenterÔ_Ô€for€adding€ether€and€attachingÐ …"˜  Ða€flexible€tube€leading€to€the€mouthpiece;€wind€a€metal€tube,€open€to€the€atmosphere€at€one€end,Ð ]$p" Ðaround€the€box,€to€warm€the€air€before€it€enters;€and€immerse€the€entire€vaporizer€in€a€basin€ofÐ 5&H!$ Ðheated€water.€ò òó óSnow€brought€his€ideas€to€Daniel€Ferguson,€instrument„maker€to€St.Ð  ( #& ÐBartholomewððs€Hospital€with€premises€in€Ô_ÔGiltspurÔ_Ô€Street,€who€agreed€to€construct€such€anÐ å)ø$( Ðapparatus.€It€would€be€ready€in€a€few€days.€Ð ½+Ð&* Ðà  àMeanwhile,€the€second€and€third€weeks€of€January€were€also€eventful€elsewhere€inÐ •-¨(, ÐLondon.€Surgeons€at€most€of€the€major€hospitals€had€tried€the€new€process€for€painlessÐ í Ðoperations,€and€many€reported€successful€outcomes.€But€there€had€been€failures,€too,€the€mostÐ ÅØ Ðabject€occurring€on€Thursday€the€14òòthóó€at€St.€Georgeððs€Hospital,€where€a€ð ðlarge€concourse€ofÐ ° Ðspectatorsðð€observed€three€botched€attempts.€The€first€patient€was€sent€back€to€the€ward€fullyÐ u ˆ Ðconscious,€when€the€ether€failed€to€have€any€effect;€the€second€patient,€thought€to€be€insensible,Ð M ` Ðstarted€bawling€when€the€surgeon€applied€the€knife€to€a€diseased€finger;€and€the€third€awokeÐ %8  Ðbefore€the€surgeon€finished€sawing€off€his€leg.€The€reporter€for€the€òòLondon€Medical€GazetteóóÐ ý  Ðnoted,€in€a€laconic€understatement,€that€ð ðthe€effect€on€the€bystanders€was€anything€but€favourableÐ Õè  Ð.€.€.€.ðð× ƒ3 ×Ý ƒ$ÓÝòòÚ  Ú23Ú  ÚóóÝ  Ý×  ×€There€was€also€considerable€buzz€about€new€inhalers€on€the€market.€Twelve€wereÐ ­À Ðpresented€and€discussed€on€the€13òòthóó€at€the€Pharmaceutical€Society,€including€a€modified€versionÐ …˜ Ðconstructed€by€Squire€ò ò(Fig.€31)€ó óand€three€that€Ferguson€had€contrived€for€different€surgeonsò òó ó.€TheÐ ]p Ðweekly€issue€of€the€òòLancetóó€on€Saturday,€the€16òòthóó€of€January,€featured€Hooperððs€latest€apparatusÐ =P Ðò ò(Fig.€32)ó ó,€based€on€designs€provided€by€Boott€and€Robinsonò òó ó.Ð ( Ðà  àThat€evening,€ð ðInhalation€of€etherðð€was€the€main€event€at€the€weekly€meeting€of€theÐ õ ÐWestminster€Medical€Society,€held€at€ò ò(Fig.€33)ó ó€Exeter€Hall€near€the€Waterloo€Bridge€(theÐ Íà Ðlocation€of€the€Strand€Palace€Hotel€today).€The€first€two€speakers€gave€accounts€of€what€theyÐ ­ À Ðconsidered€successful€uses€of€ether€at€Charing€Cross€Hospital,€despite€some€troublingÐ …"˜  Ðcomplications.€Snow€then€rose€to€his€feet€and€said€ò ò(Fig.€34)ó ó€that:Ð ]$p" Ðà0  àthe€great€effect€of€temperature€over€the€relations€of€atmospheric€air€with€the€vapour€ofÐ =&P!$ Ðether,€had€apparently€been€overlooked€in€the€construction€and€application€of€theÐ ((#& Ðinstruments€hitherto€used.€This€circumstance€would€explain€in€some€measure€the€varietyÐ í)%( Ðof€the€results,€and€account€for€some€of€the€failures.€The€operators€did€not€at€present€knowÐ Å+Ø&* Ðthe€quantity€of€vapour€they€were€exhibiting€with€the€air;€it€would€vary€immenselyÐ -°(, Ðaccording€to€the€temperature€of€the€apartment,€as€would€be€seen€by€some€calculations€heÐ í Ðhad€made,€and€suspended€in€the€room.€(ò òFig.€35ó ó)ÐÅØ(#(# ÐHe€concluded€with€a€brief€overview€of€the€apparatus€ð ðwhich€Mr.€Ferguson,€of€Smithfield,€wasÐ ¥¸ Ðmaking€for€him,ðð€based€ò ò(Fig.€36)ó ó€ð ðon€the€plan€of€the€inhaler€of€Mr.€Jeffreys,€with€someÐ }  Ðalterations€and€additions.€The€air€would€meet€with€no€obstruction€from€having€to€pass€throughÐ ] p Ðsponge€or€ether,€and€the€instrument,€which€would€be€of€metal,€as€a€good€conductor€of€caloric,Ð 5H  Ðwould€be€cheap€and€portable.ðð× ƒ7 ×Ý ƒ$ÓÝòòÚ  Ú24Ú  ÚóóÝ  Ý×  ×Ð    Ðà  àThe€following€week,€Ferguson€brought€Snow€the€inhaler€made€to€his€specifications.€SnowÐ åø  Ðtested€it€once,€was€satisfied,€and€informed€the€Secretary€of€the€Westminster€Society€that€he€wouldÐ ½Ð Ðbe€able€to€show€it€at€the€next€meeting.€The€òòLondon€Medical€Gazetteóó€for€Friday€the€22òòndóó€publishedÐ •¨ Ðthe€minutes€of€the€previous€meeting,€but€Snowððs€elaborate€table€ò ò(Fig.€37)ó ó€of€ether€Ô_ÔvaporÔ_Ô€atÐ m€ Ðdifferent€temperatures€had€been€reduced€to€five€entries€(ò òFig.€38ó ó).€Fortunately,€he€had€submittedÐ M` Ðthe€full€table€to€the€òòMedical€Timesóó,€and€it€appeared€the€following€day.× ƒŽ ×Ý ƒ$ÓÝòòÚ  Ú25Ú  ÚóóÝ  Ý×  ×€At€8:00€oððclock€thatÐ -@ Ðevening,€the€23òòrdóó,€only€a€few€dozen€members€of€the€Westminster€Medical€Society€were€inÐ  Ðattendance€when€Snow€demonstrated€his€ether€inhaler€(ò òFig.€39ó ó).€It€was€a€black,€circular€tin€boxÐ Ýð Ðabout€five€inches€in€diameter€and€nearly€three€inches€tall.€A€pewter€tube,€open€to€the€air€at€oneÐ ½ Ð Ðend,€was€coiled€around€the€box€before€entering€the€side;€Snow€believed€at€the€time€it€wasÐ •"¨  Ðnecessary€to€warm€the€air€before€it€entered€the€ether€chamber.€Inside€the€box,€Mr.€Ferguson€hadÐ m$€" Ðsoldered€a€strip€of€tin,€in€widening€spirals,€to€the€top;€this€tin€strip€reached€within€a€half€inch€ofÐ E&X!$ Ðthe€bottom€of€the€apparatus,€so€that€liquid€ether€poured€through€a€pipe€in€the€Ô_ÔcenterÔ_Ô€of€the€lidÐ (0#& Ðcould€reach€the€sides€without€obstruction.€After€adding€ether,€the€operator€would€attach€a€flexibleÐ õ)%( Ðtube,€with€an€inner€diameter€of€five„eights€of€an€inch,€to€the€central€pipe€and€then€place€theÐ Í+à&* Ðapparatus€in€a€hand€basin€containing€water€heated€to€the€temperature€required€to€produce€theÐ ¥-¸(, Ðdesired€ether„air€mixture.€For€a€mouthpiece€ò ò(Fig.€40)ó ó,€Snow€had€decided€to€use€the€one€designedÐ í Ðby€Samuel€J.€Tracy€of€Bartððs,€perhaps€on€Fergusonððs€recommendation€since€he€had€constructed€itÐ Íà Ðas€well€ò ò(Fig.€41)ó ó.× ƒ" ×Ý ƒ$ÓÝòòÚ  Ú26Ú  ÚóóÝ  Ý×  ×€The€apparatus€was€ingeniously€simple,€but€would€it€work€in€the€operatingÐ ¥¸ ÐÔ_ÔtheaterÔ_Ô?Ð … ˜ Ðà  àThe€proof€of€the€Snow„Ferguson€tin€pudding€occurred€during€three€operations€theÐ ] p Ðfollowing€Thursday€at€St.€Georgeððs€Hospital€ò ò(Fig.€42)ó ó,€Hyde€Park€Corner,€just€west€of€GreenÐ 5H  ÐPark€and€Piccadilly.€It€is€unclear€if€Snow€had€proposed€this€trial,€or€if€the€hospital€governorsÐ (  Ðfigured€they€had€little€reputation€left€to€lose€in€asking€a€local€physician€with€an€untestedÐ í  Ðapparatus€to€administer€ether€for€their€Ô_ÔskepticalÔ_Ô€surgeons.× ƒ8 ×Ý ƒ$ÓÝòòÚ  Ú27Ú  ÚóóÝ  Ý×  ×ò òó ó€The€trial€was€public,€with€spectatorsÐ ÅØ Ðand€reporters€filling€the€benches€of€the€Ô_ÔamphitheaterÔ_Ô,€and€the€circumstances€were€less€than€ideal.Ð ° ÐSnow€would€be€administering€ether€for€three€different€surgeons,€who€were€performing€three€veryÐ uˆ Ðdifferent€operations€on€three€patients€of€varying€ages€and€physical€conditions.× ƒ: ×Ý ƒ$ÓÝòòÚ  Ú28Ú  ÚóóÝ  Ý×  ×€Moreover,€hisÐ M` Ðonly€baseline€for€deciding€how€much€Ô_ÔvaporÔ_Ô€to€administer€was€one€test,€in€which€his€apparatusÐ %8 Ðheated€to€70ð$ð€produced€a€powerful€effect€in€thirty€seconds€ð!ð€but€he€had€no€idea,€as€yet,€how€longÐ ý Ðit€would€take€his€apparatus€to€produce€insensibility.× ƒ< ×Ý ƒ$ÓÝòòÚ  Ú29Ú  ÚóóÝ  Ý×  ×€When€Snow€and€the€first€surgeon,€Mr.Ð Õè ÐÔ_ÔCsarÔ_Ô€Hawkins,€were€ready,€a€nursing€sister€brought€six€year€old€William€Daphne€into€theÐ ­ À ÐÔ_ÔtheaterÔ_Ô€and€helped€him€onto€the€operating€table.€Snow€had€heated€the€basin€of€water€to€65ð$ð,Ð …"˜  Ðwhich,€according€to€his€table€ò ò(Fig.€43)ó ó,€should€deliver€about€44%€ether€Ô_ÔvaporÔ_Ô€(green€shadedÐ ]$p" Ðrectangle).€But€the€ether€supplied€by€most€hospitals€was€washed,€which€boiled€at€100ð$ð,€whereasÐ =&P!$ Ðthe€unwashed€ether€he€had€used€when€confirming€Ureððs€figures€boiled€at€104ð$ð.€Unaware€thatÐ ((#& Ðevery€temperature€entry€on€his€table€overstated€the€amount€of€ether€Ô_ÔvaporÔ_Ô,€Snow€administered€airÐ í)%( Ðsaturated€with€no€more€than€40%€ether€Ô_ÔvaporÔ_Ô€(red€shaded€rectangle),€which€young€DaphneÐ Å+Ø&* Ðinhaled€ð ðwithout€objection€or€difficulty.ðð× ƒ> ×Ý ƒ$ÓÝòòÚ  Ú30Ú  ÚóóÝ  Ý×  ×€He€was€insensible€in€less€than€two€minutes.ò òó ó€Mr.Ð -°(, ÐÔ_ÔCsarÔ_Ô€Hawkins€cut€into€the€shin€and€began€removing€dead€bone€from€the€interior€of€the€tibia.Ð í ÐAfter€a€minute,€the€boy€stopped€breathing,€and€his€face€turned€purple.€Snow€removed€theÐ ÅØ Ðmouthpiece.€When€Daphne€opened€his€eyes€and€turned€his€head,€Snow€re„applied€the€mouthpieceÐ ° Ðfor€a€couple€of€minutes€until€Ô_ÔCsarÔ_Ô€Hawkins€had€finished€what€was€normally€an€ð ðextremelyÐ u ˆ Ðpainfulðð€operation.€The€boy€awoke€and€ð ðwas€taken€away€without€shedding€a€tear.ðð€Ô_ÔCsarÔ_ÔÐ M ` ÐHawkins€was€impressed.× ƒ? ×Ý ƒ$ÓÝòòÚ  Ú31Ú  ÚóóÝ  Ý×  ×Ð %8  Ðà  àShortly€thereafter,€Mr.€Cutler€was€scheduled€to€amputate€the€thigh€of€William€Ô_ÔCowenÔ_Ô,€aÐ ý  Ðgroom€in€his€early€twenties,€who€had€been€injured€two€months€earlier€when€thrown€from€a€horse.Ð Õè  ÐInfection€had€set€in.€Snow€wanted€this€patient€to€inhale€approximately€50%€ether€Ô_ÔvaporÔ_Ô€ò ò(Fig.€44)ó ó,Ð ­À Ðso€he€increased€the€water€temperature€to€70ð$ð.€Mr.€Cutler€commenced€the€operation€after€twoÐ   Ðminutes€of€inhalation.€Snow€employed€the€same€on/off€strategy€as€in€the€first€operation,€but€withÐ ex Ðgreater€effectiveness.€Ô_ÔCowenÔ_Ô€awoke€without€stirring€or€having€experienced€any€pain.€Cutler€wasÐ =P Ðalso€impressed,€and€said€so€to€the€assembled€spectators.€Snowððs€success€continued€with€the€thirdÐ ( Ðpatient,€Francis€Lewis,€a€man€of€42€in€good€health€except€for€a€large,€fatty€Ô_ÔtumorÔ_Ô€over€his€rightÐ í Ðscapula.€Snow€added€hot€water€to€the€basin€until€the€thermometer€registered€75ð$ð€ò ò(Fig.€45)ó ó;€LewisÐ ÅØ Ðinhaled€the€ether€Ô_ÔvaporÔ_Ô€for€two€minutes.ò òó ó€Snow€nodded€to€Mr.€Ô_ÔTatumÔ_Ô,€who€began€to€excise€theÐ ¥ ¸ ÐÔ_ÔtumorÔ_Ô€as€Snow€removed€and€re„applied€the€mouthpiece€in€such€a€manner€that€Lewis€awoke€justÐ }"  Ðas€Ô_ÔTatumÔ_Ô€finished€his€task.€Lewis€said€he€had€felt€no€pain.€Ô_ÔTatumÔ_Ô€made€a€few€comments€to€theÐ U$h" Ðaudience,€and€introduced€Snow€who€explained€his€modus€operandi€for€the€three€cases.× ƒ@ ×Ý ƒ$ÓÝòòÚ  Ú32Ú  ÚóóÝ  Ý×  ׀Р-&@!$ ÐÓ  Ó*€*€*Ð (#& ÐÓçŠÓBut€why€did€Snow€consider€temperature€the€decisive€factor?€Our€view€is€that€he€approached€theÐ Ý)ð$( Ðinhalation€of€ether,€as€he€had€done€with€other€problems€in€medicine,€from€the€perspective€of€theÐ µ+È&* Ðcollateral€sciences€ð!ð€in€this€instance€as€an€experimental€chemist.€In€all€likelihood,€this€orientationÐ - (, ÐÑ¿[ Ñâ âÑ„°Ñâ âÑ  Ñbegan€during€his€apprenticeship€in€Newcastle€ò ò(Fig.€46)ó ó.€His€master,€William€Ô_ÔHardcastleÔ_Ô,€gaveÐ í Ðhim€time€to€study€the€physical€and€natural€sciences,€to€extend€his€facility€in€mathematics,€toÐ Íà Ðcomplete€a€semester€of€basic€courses,€including€chemistry,€offered€by€local€medical€men,€and€toÐ ¥¸ Ðwalk€the€wards€at€the€Newcastle€Infirmary.€At€the€Hunterian€School€of€Medicine€in€London€ò ò(Fig.Ð }  Ð47)ó ó,€Snow€took€two€chemistry€courses€from€John€Hunter€Lane,€an€Edinburgh€trained€surgeon€andÐ ] p Ðphysician,€although€the€regulations€required€only€one.× ƒb ×Ý ƒ$ÓÝòòÚ  Ú33Ú  ÚóóÝ  Ý×  ×€His€earliest€known€experiments€inÐ =P  Ðapplied€chemistry€occurred€when€he€was€a€medical€student.€At€Hunter€Laneððs€suggestion,€in€1836Ð (  Ðhe€replicated€for€the€Hunterian€school€a€continental€technique€of€injecting€vessels€in€cadaversÐ í  Ðwith€arsenic€to€clear€them€of€dried€blood€before€adding€ink.€He€repeated€the€procedure,€andÐ ÅØ Ðbecame€ill,€the€following€summer€when€the€weather€was€ð ðvery€hot.ðð€Some€time€later,€SnowÐ ° Ðconducted€a€bio„chemical€experiment€to€replicate€the€decomposition€process.€He€isolatedÐ uˆ Ðmetallic€arsenic€from€the€emitted€gases,€and€later€published€his€findings€in€the€òòLancetóó€ò ò(Fig.€48)ó ó,Ð M` Ðhis€first€publication€in€a€medical€journal.× ƒc ×Ý ƒ$ÓÝòòÚ  Ú34Ú  ÚóóÝ  Ý×  ×€At€the€time,€he€lived€on€Frith€Streetò ò€(Fig.€49)ó ó,€a€shortÐ -@ Ðif€circuitous€walking€distance€from€where€he€had€lodged€as€a€medical€student€ò ò(Fig.€50)ó ó.€In€the€fallÐ    Ðof€1837,€when€the€Westminster€Medical€Society€debated€whether€to€formally€condemn€theÐ í Ðmanufacture€and€sale€of€stearin€candles€containing€arsenic,€a€Select€Committee€conductedÐ Å Ø Ðexperiments€on€birds,€rabbits,€and€guinea€pigs.€ò òó óWhen€the€Committee€reported€mixed€results,Ð "°  ÐSnow,€who€ð ðhad€succeeded€in€detecting€arsenious€acid€in€these€lights,ðð€was€dissatisfied.€In€aÐ u$ˆ" Ðsuggestive€prelude€to€his€criticism€during€the€early€weeks€of€inhalation€ether€a€decade€later,€SnowÐ M&`!$ Ðrepeated€the€animal€experiments€at€different€temperatures€because€he€believed€that€the€SelectÐ %(8#& ÐCommittee€had€erred€in€relying€on€the€ambient€temperature€in€the€room,€which€varied€widelyÐ ý)%( Ðover€several€days.× ƒd ×Ý ƒ$ÓÝòòÚ  Ú35Ú  ÚóóÝ  Ý×  ׀РÕ+è&* Ðà  àAfter€qualifying€as€a€surgeon„apothecary€in€1838,€Snow€continued€to€demonstrate€a€livelyÐ ­-À(, Ðinterest€in€possible€chemical€explanations€for€the€medical€and€public€health€problems€of€his€time.Ð í ÐFor€example,€the€Westminster€Society€became€quite€exercised€in€1839€about€smoke€seeping€fromÐ ÅØ Ðstoves,€considering€in€particular€whether€death€occurred€by€asphyxia€or€because€carbonic€acidÐ ° Ðacted€as€a€specific€poison.€Snow€upped€the€ante.€He€presented€critiques€of€the€scholarly€literature,Ð u ˆ Ðconducted€biochemical€experiments,€some€on€small€animals,€many€on€himself,€and€preparedÐ M ` Ðtables€of€his€findings.€Shortly€before€Morton€announced€his€discovery€of€inhalation€ether,€SnowÐ %8  Ðreplicated€some€of€his€1839€experiments€and€published€them€after€reading€of€an€ill„advisedÐ ý  Ðproposal€for€ð ðabsorbing€the€carbonic€acid€gas€remaining€after€the€explosion€of€fire„damp€in€coalÐ Õè  ÐminesÔUSCE.,Ô,ðð€which€was€made,€in€his€view,€without€due€consideration€for€the€diminution€of€oxygenÐ ­À Ðcaused€by€such€explosions.× ƒe ×Ý ƒ$ÓÝòòÚ  Ú36Ú  ÚóóÝ  Ý×  ×€With€this€background€in€mind,€it€seems€less€surprising€that€SnowÐ …˜ Ðresponded€to€his€observations€of€the€inhalation€of€ether€as€a€chemist,€who€wondered€ò ò(Fig.€51)ó óÐ ]p Ðwhether€ð ðby€regulating€the€temperature€of€the€air€whilst€it€is€exposed€to€the€ether,€we€should€haveÐ =P Ðthe€means€of€ascertaining€and€adjusting€the€quantity€of€Ô_ÔvapourÔ_Ô€that€will€be€contained€in€it:€for€theÐ ( Ðproportion€of€Ô_ÔvapourÔ_Ô€in€any€given€volume€of€air€saturated€with€it€at€any€particular€temperature,€isÐ í Ðto€the€whole€volume€as€the€elastic€force€of€the€Ô_ÔvapourÔ_Ô€at€that€temperature€is€to€the€atmosphericÐ ÅØ Ðpressure€at€the€time€and€place.€This€is€true€of€all€Ô_ÔvapoursÔ_Ô€in€contact€with€the€liquid€which€givesÐ  ° Ðthem€off.ðð× ƒf ×Ý ƒ$ÓÝòòÚ  Ú37Ú  ÚóóÝ  Ý×  ×€As€we€have€seen,€he€used€all€of€January€1847€to€investigate€the€deductiveÐ u"ˆ  Ðimplications€(chemically,€technologically,€and€finally€clinically)€of€this€hypothesis.€Then,€for€theÐ M$`" Ðnext€eight€weeks,€he€was€an€exemplar€of€John€Herschelððs€dictum€ò ò(Fig.€52)ó ó,€ð ðthat€the€successfulÐ %&8!$ Ðprocess€of€scientific€enquiry€demands€continually€the€alternative€use€of€both€the€òòinductiveóó€andÐ (#& Ðòòdeductiveóó€method.Ô_Ô× ƒg ×Ý ƒ$ÓÝòòÚ  Ú38Ú  ÚóóÝ  Ý×  ×Ô_ÔÐ Ý)ð$( ÐÓ  Ó*€*€*Ð µ+È&* ÐÓõ¢ÓAlthough€the€exhibition€of€his€apparatus€on€the€28òòthóó€of€January€was€very€successful,€Snow€wasÐ - (, Ðtroubled.€It€lacked€a€mechanism€that€would€permit€him€to€control€the€amount€of€vapor€the€patientÐ í Ðinhaled€at€any€particular€moment.€Removing€the€mouthpiece€from€patients€if€their€breathingÐ ÅØ Ðbecame€labored€was€awkward,€and€the€sudden€inhalation€of€approximately€50%€ether€could€alsoÐ ° Ðbe€an€irritant.€So€Snow€consulted€Ferguson,€and€the€two€decidedò òó ó€that€a€brass€two„way€valve€withÐ u ˆ Ða€handle€ò ò(Fig.€53)ó óÔCE.,US.,ž›ÔÔUSCE.,Ô,€inserted€into€the€top€of€the€spiral€ether€chamber,€would€allow€Snow€to€easeÐ M ` Ðthe€patients€into€full€Ô_ÔetherizationÔ_Ô€as€well€as€to€adjust€the€strength€of€the€ether/air€mixture€duringÐ -@  Ðthe€operation€itself.Ô_Ô× ƒi ×Ý ƒ$ÓÝòòÚ  Ú39Ú  ÚóóÝ  Ý×  ×Ô_Ô€Ferguson€quickly€completed€a€modified€apparatus€(the€Mark€II€model,Ð   Ðaccording€to€Richard€Ellisðð€taxonomy),€and€Snow€used€it€for€three€operations€at€St.€Georgeððs€onÐ Ýð  Ðthe€4òòthóó€of€February.€The€theater€that€day€was€packed€with€ð ða€numerous€assembly€of€spectators,ððÐ µÈ Ðincluding€a€reporter€from€the€òòLancetóó€who€made€note€of€Snowððs€revised€procedure.× ƒ ×Ý ƒ$ÓÝòòÚ  Ú40Ú  ÚóóÝ  Ý×  ×ÔCE.,US.,£¥ÔÔUSCE.,Ô€WithÐ   Ðmouthpiece€in€place,€Snow€turned€the€valve€on€his€apparatus€so€the€patient€began€breathing€onlyÐ ex Ðatmospheric€air.€After€a€short€time€he€gradually€turned€the€valve€during€successive€inspirations,Ð =P Ðuntil€the€patient€was€inhaling€the€full€strength€of€ether€vapor€at€the€desired€temperature.€ò òó óSnowÐ ( Ðobserved€the€patientððs€eyes€and€the€character€of€the€respiration€for€signs€of€complete€insensibility,Ð í Ðthen€nodded€to€Ô_ÔCsarÔ_Ô€Hawkins,€who€began€removing€dead€bone€from€the€womanððs€tibia.€SnowÐ ÅØ Ðadjusted€the€valve€several€times€to€keep€the€patient€both€unconscious€and€insensible€to€pain,Ð  ° Ðusing€the€least€amount€of€ether€vapor€necessary.€Before€Ô_ÔCsarÔ_Ô€Hawkins€finished,€Snow€turnedÐ u"ˆ  Ðthe€valve€to€admit€only€air,€and€the€patient€awoke€during€suturing.€She€had€felt€no€pain.€TheÐ M$`" Ðsecond€operation€went€almost€as€well.€The€patient€groaned€somewhat€at€the€beginning,€butÐ %&8!$ Ðdeclared€afterward€that€he€had€felt€no€pain;€the€òòLancetóó€reporter€wondered€if€the€first€incision€wasÐ ý'#& Ðslightly€premature.€The€third€was€a€complete€success,€however.€Afterward,€Snow€described€hisÐ Õ)è$( Ðnew€procedure€and€credited€Ferguson€for€making€it€possible.€Ô_ÔCsarÔ_Ô€Hawkins€concluded€theÐ ­+À&* Ðmorning€by€expressing€thanks,€in€behalf€of€his€colleagues€at€the€hospital,€to€Snow€for€hisÐ …-˜(, Ðð ðsuperiorðð€apparatus€that€permitted€the€administration€of€controlled€amounts€of€ether€vapor.× ƒm ×Ý ƒ$ÓÝòòÚ  Ú41Ú  ÚóóÝ  Ý×  ×€InÐ í Ðother€words,€Snow€had€become€anesthetist€at€St.€Georgeððs€Hospital€ð!ð€an€unpaid€position,€but€oneÐ ÅØ Ðthat€guaranteed€an€expansion€of€his€private€practice.Ð ° Ðà  àSurgical€operations€at€St.€Georgeððs€were€performed€on€Thursday€mornings,€except€forÐ u ˆ Ðemergencies,€so€Snow€used€the€intervening€week€to€prepare€a€paper€reviewing€his€researches€andÐ M ` Ðadministrations€to€date.€On€11€February,€he€was€in€the€operating€theater€at€St.€Georgeððs€again.Ð %8  ÐThe€first€operation,€a€Ô_ÔlithotomyÔ_Ô€on€a€four€year€old€boy,€had€the€indirect€outcome€of€highlightingÐ ý  Ðthe€effectiveness€of€Snowððs€inhaler€and€procedure.€As€Mr.€Cutler€purposely€inserted€the€soundÐ Õè  Ðbefore€Ô_ÔetherizationÔ_Ô€had€begun,€the€boy€cried€lustily;€but€he€stopped€crying€within€seconds€ofÐ ­À ÐSnow€administering€ether,€and€remained€insensible€while€Mr.€Cutler€searched€for€the€offendingÐ …˜ Ðstone,€found€it,€and€extracted€a€calculus€the€size€of€a€pigeonððs€egg.€Snow€removed€theÐ ]p Ðmouthpiece,€and€the€boy€was€soon€fully€awake.€During€the€second€operation,€a€mastectomy,Ð 5H ÐSnow€opened€the€two„way€tap€on€his€apparatus€fully€to€atmospheric€air,€then€gradually€turned€itÐ    Ðto€increase€the€amount€of€ether€vapor.€After€four€minutes€the€woman€was€till€fully€sensible,€butÐ åø Ðð ðrather€out€of€breath.ðð× ƒ) ×Ý ƒ$ÓÝòòÚ  Ú42Ú  ÚóóÝ  Ý×  ×€Snow€must€have€been€puzzled.€This€had€not€happened€in€the€previousÐ ½Ð Ðseven€operations.€He€checked€the€apparatus,€and€observed€that€the€inlet€pipe€to€the€ether€chamberÐ • ¨ Ðwas€capped€ò ò(Fig.€54)ó ó.€In€the€words€of€the€òòLancetóó€reporter,€ð ðshe€got€no€ether,€and€but€little€air.ððÐ m"€  ÐSnow€immediately€unscrewed€the€cap.€The€sudden€inhalation€of€50%€ether€set€in€motion€a€trainÐ M$`" Ðof€events€that€Snowððs€modified€apparatus€and€procedure€were€designed€to€avoid:€ð ðSomeÐ %&8!$ Ðcoughing,€and€in€three€or€four€minutes€the€face€was€becoming€purple,€and€the€pulse€feeble€andÐ ý'#& Ðquick,€and€the€features€rather€distorted.ðð€Snow€removed€the€mouthpiece€and€stood€by€as€theÐ Õ)è$( Ðsurgeon,€Mr.€H.€Charles€Johnson,€amputated€the€breast€without€the€benefit€of€controlledÐ ­+À&* ÐÔ_ÔetherizationÔ_Ô.€The€patient€struggled€and€moaned,€but€afterwards€said€she€did€not€remember€feelingÐ …-˜(, Ðany€pain.€Mr.€Johnson€made€no€mention€of€Snowððs€error,€if€he€even€he€even€recognized€it,€in€hisÐ í Ðconcluding€comments.€He€thought€that€perhaps€the€patientððs€pre„existing€bronchitis€was€theÐ ÅØ Ðlikely€reason€that€the€ether€ð ðhad€somewhat€disagreed€with€her.ððÔ_Ô× ƒn ×Ý ƒ$ÓÝòòÚ  Ú43Ú  ÚóóÝ  Ý×  ×Ô_ԀР° Ðà  àHow€could€Snow€have€made€such€an€elementary€mistake,€given€his€earlier€successes?Ð u ˆ ÐOne€possibility€is€that€he€had€not€incorporated€into€his€routine€another€of€FergusonððsÐ M ` Ðmodifications€to€the€prototype€inhaler€ð!ð€a€screw€cap€on€the€air€intake€pipe€encircling€the€outsideÐ %8  Ðof€the€ether€chamber€ò ò(Fig.€55)ó ó.€The€intake€pipe€of€the€prototype€had€been€uncapped.€FergusonÐ ý  Ðhad€also€added€a€separate€aperture€for€pouring€ether€into€the€chamber,€probably€so€that€the€two„Ð Ýð  Ðway€tap€could€be€soldered€to€the€lid.€Although€Snow€and€the€journals€only€mentioned€the€latterÐ µÈ Ðwhen€describing€the€new€apparatus€he€had€introduced€on€the€4òòthóó€of€February,€it€seems€likely€thatÐ   ÐFerguson€made€all€three€modifications€at€the€same€time.Ô_Ô× ƒo ×Ý ƒ$ÓÝòòÚ  Ú44Ú  ÚóóÝ  Ý×  ×Ô_ÔÐ ex Ðà  àTwo€days€later,€the€13òòthóó€of€February,€at€the€Westminster€Medical€Society,€Snow€read€aÐ =P Ðpaper€ò ò(Fig.€56)ó ó€on€ether€vapor€and€its€use€in€surgical€operations.× ƒp ×Ý ƒ$ÓÝòòÚ  Ú45Ú  ÚóóÝ  Ý×  ×€He€began€with€theÐ ( Ðpharmacological€effects€of€ether€inhalation.€His€ether€uptake€table€ò ò(Fig.€57)ó ó€showed€that€in€anyÐ õ Ðsaturated€volume€of€air-ether€mixture,€the€ether€Ô_ÔvapourÔ_Ô€displaced€a€certain€quantity€of€air,€theÐ Õè Ðamount€depending€on€the€temperature.€At€70ððF,€the€temperature€he€generally€preferred€forÐ ­ À Ðinhalation€during€surgical€operations,€the€mixture€should€contain€almost€50%€ether€vapor€(he€isÐ …"˜  Ðstill€unaware€that€his€table€is€slightly€inaccurate€for€unwashed€ether).€Since€such€a€concentrationÐ ]$p" Ðwould€reduce€the€amount€of€oxygen€in€each€breath€by€half,€he€had€been€concerned€to€investigateÐ 5&H!$ Ðwhether€the€anesthetic€effect€was€due€to€asphyxia,€which€opponents€of€ether€inhalation€arguedÐ  ( #& Ðmade€the€procedure€a€hazardous€way€to€relieve€the€momentary€pains€of€a€surgical€operation.€SoÐ å)ø$( ÐSnow€conducted€experiments€on€mice€to€determine€whether€ether€produced€insensibility€byÐ ½+Ð&* Ðexcluding€oxygen€from€inspired€air.€ò ò(Fig.€58)ó ó€ð ðSuch,€however,€was€not€the€case,€for€he€found€thatÐ •-¨(, Ðsupplying€the€displaced€oxygen€did€not€counteract€the€effects€of€the€Ô_ÔvapourÔ_Ô.€Mixed€with€oxygenÐ í Ðgas€it€affected€mice€as€powerfully€as€when€mixed€with€the€air,€as€he€had€found€in€severalÐ ÅØ Ðexperiments.€Asphyxia€was€a€very€different€state€from€that€produced€by€etherðð€(383).€Asphyxia,Ð ° Ðwhile€it€produced€insensibility€to€pain,€was€a€great€danger€to€life,€and€ended€in€death.€This€wasÐ u ˆ Ðnot€true€of€ether,ò òó ó€which€ð ðallowed€the€blood€to€be€changed€from€venous€to€arterial€in€the€lungs,Ð M ` Ðbut€probably€interfered€with€the€changes€which€take€place€in€the€capillaries€of€the€system.€ò ò[Fig.Ð %8  Ð59]ó ó€He€had€ascertained€that€a€little€Ô_ÔvapourÔ_Ô€of€ether€mixed€with€air€would€prevent€the€oxidation€ofÐ   Ðphosphorus€placed€in€it,€and€considered€that€it€had€a€similar€effect€over€the€oxygen€in€the€blood,Ð åø  Ðand€reduced€to€a€minimum€the€oxidation€of€nervous€and€other€tissuesðð€(383).€Snow€was€referringÐ ½Ð Ðto€an€observation€made€by€Thomas€Graham€in€1829,€that€the€presence€of€certain€vapors,Ð •¨ Ðincluding€sulphuric€ether,€would€inhibit€the€slow€oxidation€of€phosphorus€in€air.ò òó ó€That€SnowÐ m€ Ðknew€of€this€observation€argues€a€close€acquaintance€with€the€literature€of€experimentalÐ EX Ðchemistry€ð!ð€and€buttresses€our€argument€that€Ô_ÔconsilientÔ_Ô€factors€partly€explains€why€Snow€was€soÐ 0 Ðquick€to€become€an€authority€on€ether€inhalation.€By€using€this€reaction€as€an€analogy,€andÐ õ Ðtransferring€the€effect€from€vitro€to€vivo,€Snow€implicitly€declared€himself€not€a€vitalist.€In€anÐ Íà Ð1843€article€on€circulation,€he€had€already€situated€himself€among€contemporaries€who€wonderedÐ ¥ ¸ Ðwhether€the€chemical€reactions€that€maintained€body€heat,€which€involved€the€removal€of€oxygenÐ }"  Ðfrom€the€blood€and€the€production€of€carbon€dioxide,€took€place€in€the€terminal€capillaries,€ratherÐ U$h" Ðthan,€as€was€thought€by€Ô_ÔLavoisierÔ_Ô,€in€the€lungs.Ô_Ô× ƒu ×Ý ƒ$ÓÝòòÚ  Ú46Ú  ÚóóÝ  Ý×  ×Ô_Ô€Snow€concluded€his€paper€with€some€practicalÐ -&@!$ Ðobservations€and€advice.€Induction€of€anaesthesia€should€be€as€rapid€as€possible.€The€depth€ofÐ (#& Ðanesthesia€could€be€determined€by€observation€of€the€eye€and€the€nature€of€the€respiration€(deep,Ð Ý)ð$( Ðslow,€automatic,€but€never€stertorous).€There€should€be€no€flinching€or€groaning€when€touchedÐ µ+È&* Ðby€the€knife,€whether€or€not€the€patient€remembered€any€pain.€Ô_ÔEtherizationÔ_Ô€affectedÐ - (, Ðconsciousness€before€sensation.€He€then€described€how€his€modified€apparatus€permitted€him€toÐ í Ðcontrol€the€amount€of€ether€inhaled€at€any€time.€He€recommended€that€inhalation€should€alwaysÐ ÅØ Ðbegin€with€100%€air,€then€gradually€increasing€the€strength€of€ether€vapor€by€turning€the€valveÐ ° Ðuntil€the€patient€was€inhaling€entirely€via€the€apparatus.€Thereafter,€the€two„way€tap€should€beÐ u ˆ Ðturned€as€needed€to€maintain€insensibility€with€the€minimum€amount€of€ether€vapor.Ð M ` Ðà  àSnowððs€paper€occupied€almost€the€entire€evening€of€February€13,€so€discussion€wasÐ %8  Ðdeferred€until€the€following€Saturday.€For€some€reason,€Snow€decided€his€comments€on€theÐ ý  Ðpossible€modus€operandi€of€ether€required€buttressing.€There€were€no€operations€at€St.€GeorgeððsÐ Õè  Ðon€the€18òòthóó,€so€he€used€whatever€free€time€he€could€squeeze€from€his€general€practice€for€furtherÐ ­À Ðresearch.€Precisely€what€he€did€is€unclear,€since€the€minutes€for€the€20òòthóó€of€February€record€onlyÐ …˜ Ðthat€Snow€said€he€ð ðhad€completed€some€experimentsðð€since€reading€his€paper€the€week€before.× ƒr ×Ý ƒ$ÓÝòòÚ  Ú47Ú  ÚóóÝ  Ý×  ׀Р]p ÐBut€four€years€later,€he€wrote€ò ò(Fig.€60)ó ó€that€ð ðsoon€after€the€introduction€of€the€inhalation€of€ether,Ð 5H ÐI€made€some€observations€on€the€amount€of€carbonic€acid€gas€exhaled€from€the€lungs€under€itsÐ ( Ðinfluence,€by€passing€the€expired€air€through€lime€water,€when€I€found€the€quantity€to€beÐ í Ðdiminished.ðð× ƒq ×Ý ƒ$ÓÝòòÚ  Ú48Ú  ÚóóÝ  Ý×  ×€It€is€quite€possible€that€he€had€repeated€the€procedures€he€used€in€the€series€ofÐ ÅØ Ðexperiments€conducted€in€1839€on€asphyxia€and€carbon€dioxide€poisoning.€In€one€set€ofÐ  ° Ðexperiments€on€white€mice€and€sparrows,€ð ðthe€small€quantity€of€carbonic€acid€gas€given€off€fromÐ u"ˆ  Ðthe€lungs€of€the€Ô_Ôanimal[sÔ_Ô]€was€absorbed€by€lime€water.ðð× ƒ× ×Ý ƒ$ÓÝòòÚ  Ú49Ú  ÚóóÝ  Ý×  ×€In€February€1847€he€could€have€usedÐ M$`" Ðmice€or€birds,€filtered€the€lime€water,€washed€and€dried€the€deposit,€and€weighed€it,€comparingÐ %&8!$ Ðthe€quantity€produced€by€the€same€animals€during€equal€durations€of€time,€first€conscious,€thenÐ ý'#& Ðunder€the€influence€of€ether.Ô_Ô× ƒà ×Ý ƒ$ÓÝòòÚ  Ú50Ú  ÚóóÝ  Ý×  ×Ô_Ô€It€is€also€unclear€how€he€determined€that€ð ðthe€Ô_ÔvapourÔ_Ô€of€ether€wasÐ Õ)è$( Ðgiven€out€again€from€the€lungs€unchanged,ðð€but€he€may€have€exhaled€ether€via€a€spiral€tube€into€aÐ ­+À&* Ðbottle€of€sulphuric€acid,€which€was€then€treated€and€compared€with€a€similar€test€on€pure€ether.× ƒx ×Ý ƒ$ÓÝòòÚ  Ú51Ú  ÚóóÝ  Ý×  ×Ð …-˜(, ÐSnow€was€satisfied€with€whatever€experimentation€he€undertook,€for€the€secretary€recorded€himÐ í Ðas€stating€that€ð ðthese€circumstances€he€considered€confirmed€the€explanation€of€the€modusÐ ÅØ Ðoperandi€of€ether€ò ò[(Fig.€61)]ó ó€which€he€had€previously€given.ðð× ƒv ×Ý ƒ$ÓÝòòÚ  Ú52Ú  ÚóóÝ  Ý×  ×€ò òó óFor€Snow,€at€least,€anotherÐ ° Ðhighlight€of€the€evening€must€have€come€when€a€colleague€said€ð ðhe€had€seen€Dr.€SnowððsÐ }  Ðinstrument€used€on€many€occasionsðð€and€then€enumerated€its€advantages€ð ðover€all€others.ððÔ_Ô× ƒz ×Ý ƒ$ÓÝòòÚ  Ú53Ú  ÚóóÝ  Ý×  ×Ô_ÔÐ U h Ðà  àSnow,€however,€was€still€unsatisfied.€In€order€for€his€apparatus€to€work€as€designed,€andÐ -@  Ðto€know€the€precise€dosage€of€ether€vapor€he€was€administering,€the€patientððs€mouth€and€nostrilsÐ   Ðmust€be€completely€closed€to€outside€air.€The€original€Tracy€mouthpiece€ò ò(Fig.€62)ó ó€described€inÐ Ýð  Ðmid„January€1847€was€similar€to€others€ð ðin€ordinary€useðð€ð!ð€most€likely,€tube€and€valvesÐ ½Ð Ðdeveloped€by€John€Read€ð!ð€and,€like€them,€required€a€separate€nose€clip,€which€some€patientsÐ •¨ Ðfound€disagreeable.× ƒ– ×Ý ƒ$ÓÝòòÚ  Ú54Ú  ÚóóÝ  Ý×  ×€Within€two€weeks,€however,€Tracy€had€developed€a€new€mouthpiece€thatÐ m€ Ðenclosed€the€nostrils.× ƒ° ×Ý ƒ$ÓÝòòÚ  Ú55Ú  ÚóóÝ  Ý×  ×€Some€time€in€February,€Snow€decided€to€employ€the€modified€TracyÐ EX Ðmouthpiece€ð!ð€ò ò(Fig.€63)ó ó€a€combination€pad€of€flannel,€morocco€leather,€and€rubber.€Snow€didÐ 0 Ðmake€a€telling€modification€ò ò(Fig.€64)ó ó,€again€indicative€of€the€Ô_ÔconsilientÔ_Ô€experience€he€brought€toÐ ý Ðbear€on€everything€relating€to€ether€inhalation:€he€substituted€common€for€vulcanized€rubber,Ð Ýð Ðbecause€ð ðthe€latter€frequently,€if€not€always,€contains€sulphuret€of€arsenic.ððÔ_Ô× ƒy ×Ý ƒ$ÓÝòòÚ  Ú56Ú  ÚóóÝ  Ý×  ×Ô_Ô€He€had€notÐ µ È Ðforgotten€his€experiments€on€arsenic€toxicity€in€cadavers€and€candles€while€a€medical€student€atÐ "   Ðthe€Ô_ÔHunterianÔ_Ô.€Since€Tracy€did€not€describe€his€new€mouthpiece€until€after€Snow€and€FergusonÐ e$x" Ðhad€added€the€two„way€tap€to€the€prototype€in€late€January/early€February,€there€was€a€periodÐ =&P!$ Ðò ò(Fig.€65)ó ó€when€the€Mark„II€inhaler€included€the€original€Tracy€mouthpiece.€Ð ((#& Ðà  àIt€had€been€Snowððs€habit€for€several€years€to€submit€copies€of€the€papers€he€read€ratherÐ õ)%( Ðthan€rely€on€journal€reporters€and€the€minutes€to€convey€his€argument;€so,€elaborating€thisÐ Í+à&* Ðprocedure,€during€the€second€half€of€February€he€began€preparing€a€formal€article€on€etherÐ ¥-¸(, Ðinhalation€for€his€preferred€journal,€the€òòLondon€Medical€Gazetteóó.€Meanwhile,€on€the€25òòthóó€he€againÐ í Ðadministered€ether€during€three€major€surgical€operations€at€St.€Georgeððs€Hospital€ð ðwith€theÐ ÅØ Ðeffect€of€completely€removing€pain.ðð× ƒ{ ×Ý ƒ$ÓÝòòÚ  Ú57Ú  ÚóóÝ  Ý×  ×€Two€days€later,€at€the€Westminster€Medical€Society,€SnowÐ ° Ðdemonstrated€the€transient€effects€of€ether,€when€properly€administered,€on€a€ò ò(Fig.€66)ó ó€GreenÐ u ˆ ÐLinnet€ð!ð€the€common€name€in€Yorkshire€for€the€Ô_ÔGreenfinchÔ_Ô,€which€were€captured,€along€withÐ U h Ð(Red)€Linnets,€by€the€thousands,€then€caged€and€sold€on€market€days€throughout€England.× ƒ¼ ×Ý ƒ$ÓÝòòÚ  Ú58Ú  ÚóóÝ  Ý×  ×€SnowÐ -@  Ðput€a€few€drops€of€ether€into€a€glass€jar,€then€inserted€a€linnet€ò ò(Fig.€67)ó ó.€It€was€insensible€within€aÐ   Ðminute.€Snow€waited€another€minute€until€the€bird€had€nearly€ceased€breathing,€quickly€withdrewÐ åø  Ðit€from€the€jar,€and€explained€that€the€gradual€recovery€of€full€activity€was€due€to€progressiveÐ ½Ð Ðexhalation€of€ether€that€had€become€soluble€in€the€blood€ð!ð€as€distinct€from€asphyxia,€where€theÐ •¨ Ðrecovery€would€have€been€almost€immediate€under€these€conditions.× ƒ| ×Ý ƒ$ÓÝòòÚ  Ú59Ú  ÚóóÝ  Ý×  ×€ò òó óThe€Society€€then€resumedÐ m€ Ðthe€adjourned€discussion€of€ether€and€Snowððs€paper.€One€member€opined€that€proper€techniqueÐ EX Ðalways€trumped€the€kind€of€apparatus€used,€and€rendered€the€question€of€temperature€irrelevant.Ð 0 Ðð ðDr.€Snow,€in€his€reply,€spoke€of€the€necessity€of€being€able€to€regulate€the€proportion€of€etherÐ õ Ðvapour€and€of€air,ðð€an€impossibility€if€one€employed€glass€instruments€with€sponges.× ƒ ×Ý ƒ$ÓÝòòÚ  Ú60Ú  ÚóóÝ  Ý×  ×€On€the€1òòstóóÐ Íà Ðof€March,€the€òòPharmaceutical€Journalóó€published€a€very€belated€description€of€Snowððs€first€inhalerÐ ¥ ¸ Ðð!ð€the€one€already€superceded€by€the€addition€of€a€two„way€tap€ð!ð€and€alluded€to€ð ða€remarkableÐ }"  Ðcoincidenceðð€ò ò(Fig.€68)ó ó€between€Snowððs€design€and€an€illustration€of€ð ðMr.€Jefferyððs€[sic]Ð U$h" ÐApparatus.ðð× ƒ} ×Ý ƒ$ÓÝòòÚ  Ú61Ú  ÚóóÝ  Ý×  ×€Snow€fired€off€a€blistering€letter€to€the€editor:€ò ò(Fig.€69)ó ó€ð ðit€is€not€a€coincidence,€butÐ 5&H!$ Ðis€the€result€of€my€previous€acquaintance€with€the€former,€and€approval€of€it;€.€.€.€I€have€neverÐ ((#& Ðfailed€to€mention€the€circumstances€when€saying€or€writing€anything€about€the€apparatus.ðð€ForÐ í)%( Ðgood€measure€he€quoted€extracts€from€the€òòLondon€Medical€Gazetteóó€and€the€òòLancetóó.× ƒ ×Ý ƒ$ÓÝòòÚ  Ú62Ú  ÚóóÝ  Ý×  ×€OnÐ Å+Ø&* ÐThursday,€the€4òòthóó€of€March,€there€were€two€amputations€at€St.€Georgeððs€ò ò(Fig.€70)ó ó;€ð ðin€these€.€.€.Ð -°(, Ðthe€Ô_ÔvapourÔ_Ô,€which€was€given€by€Dr.€Snow€with€an€equal€volume€of€air€until€insensibility€wasÐ í Ðinduced,€was€continued€in€a€much€more€diluted€state€during€the€operations,€and€the€patients€wereÐ ÅØ Ðalso€allowed€to€take€two€or€three€inspirations€of€the€external€air,€now€and€then,€by€the€nostrils.ðð× ƒ€ ×Ý ƒ$ÓÝòòÚ  Ú63Ú  ÚóóÝ  Ý×  ×Ð ° ÐThis€should€not€be€necessary€if€his€apparatus€was€functioning€as€designed.€Snow€checked€hisÐ u ˆ Ðcase€notes,€believed€he€had€isolated€the€problem,€and€submitted€his€manuscript€for€publicationÐ M ` Ðshortly€thereafter.Ô_Ô× ƒ… ×Ý ƒ$ÓÝòòÚ  Ú64Ú  ÚóóÝ  Ý×  ×Ô_ÔÐ %8  Ðà  àThe€òòLondon€Medical€Gazetteóó€published€ð ðOn€the€Inhalation€of€the€Ô_ÔVapourÔ_Ô€of€Ether,ðð€ò ò(Fig.Ð ý  Ð71)ó ó€in€two€parts,€the€first€on€March€19.€Like€Beethoven€in€the€opening€bars€of€his€fifth€symphony,Ð Ýð  Ðhe€immediately€hammered€out€his€principle€theme€ò ò(Fig.€72)ó ó.€ð ðIt€will€be€at€once€admitted€that€theÐ ½Ð Ðmedical€practitioner€ought€to€be€acquainted€with€the€strength€of€the€various€compounds€which€heÐ ° Ðapplies€as€remedial€agents,€and€that€he€ought,€if€possible,€to€be€able€to€regulate€their€potency.€TheÐ uˆ Ðcompound€of€ether€Ô_ÔvapourÔ_Ô€and€air€is€no€exception€to€this€rule,ðð€although€most€practitionersÐ M` Ðseemed€to€think€that€all€one€could€do€after€administering€it€was€to€stand€by€and€observe€itsÐ %8 Ðeffects.€On€the€contrary,€Snow€insisted€that€its€effects€varied€with€the€proportion€of€ether€to€air,Ð ý Ðwhich€is€within€our€control.€In€addition,€with€a€proper€apparatus,€we€can€also€make€certain€thatÐ Õè Ðpatients€inhale€more€ether€than€they€exhale€in€order€to€achieve€full€insensibility€(a€fundamentalÐ ­ À Ðpremise€of€what€would€later€be€termed€Ô_ÔpharmacodynamicsÔ_Ô).ò òó ó€In€his€view,€breathing€overly€dilutedÐ …"˜  Ðether€vapor,€not€constitutional€factors,€explained€most€failures€with€ether€inhalation.€SnowÐ ]$p" Ðconcluded€the€opening€paragraph€with€a€Ô_ÔreductionisticÔ_Ô€assertion€that€justified€his€biochemicalÐ 5&H!$ Ðresearch€agenda:€ð ðI€believe€that€no€sentient€being€is€proof€against€its€influence.ððÔ_Ô× ƒ‚ ×Ý ƒ$ÓÝòòÚ  Ú65Ú  ÚóóÝ  Ý×  ×Ô_ԀР ( #& Ðà  àMost€of€part€one€consisted€of€a€review€of€Snowððs€early€reasoning€and€chemicalÐ å)ø$( Ðexperimentation.€It€did€contain€something€new,€however€ð!ð€Snowððs€realization€that€his€ether€vaporÐ ½+Ð&* Ðtable€was€misleading€if€used€to€determine€how€much€unwashed€ether€to€administer€duringÐ •-¨(, Ðoperations.€The€correction€was€easily€made€by€subtracting€four€degrees€in€the€temperatureÐ í Ðcolumn;€the€percentages€and€weights€were€accurate.× ƒƒ ×Ý ƒ$ÓÝòòÚ  Ú66Ú  ÚóóÝ  Ý×  ×€ò ò(Fig.€73)ó ó€But€instead€of€printing€aÐ ÅØ Ðcorrected€table€in€the€article,€Snow€had€prepared€a€new€table€ò ò(Fig.€74)ó ó€on€a€different€plan,Ð ¥¸ Ðshowing€the€amount€of€washed€ether€vapor€that€100€cubic€inches€would€take€up€at€differentÐ … ˜ Ðtemperatures,€which€he€believed€was€more€accessible€to€the€average€practitioner€ð ðunaccustomedÐ ] p Ðfor€a€long€period€to€arithmetical€calculationsðð€(ð ðÔ_ÔIVEÔ_Ô,ðð€499).ò òó ó€He€explained€how€the€Mark€IIÐ 5H  Ðapparatus€ò ò(Fig.€75)ó ó€was€designed€to€take€advantage€of€the€relationship€between€the€temperatureÐ    Ðof€the€air€and€amount€of€ether€vapor€expressed€in€either€table,€restated€his€indebtedness€toÐ í  ÐÔ_ÔJeffreysÔ_Ô€for€the€idea€of€a€spiral€ether€chamber€ò ò(Fig.€76)ó ó,€complimented€Ferguson€on€his€skillfulÐ ÅØ Ðcontrivances,€and€mentioned€his€preference€for€the€latest€Tracy€mouthpiece.€Ð ¥¸ Ðà  àPart€two,€in€the€following€number,€ò òó ófeatured€Snowððs€description€of€the€procedure€for€etherÐ } Ðinhalation€he€employed€and€his€clinical€observations€of€patients€undergoing€surgical€operations.€Ð Uh Ðò òó óOne€thing€was€paramount€ð!ð€ð ðthe€shorter€the€process€the€betterðð€(502).€Constricted€pupils,€withÐ -@ Ðthe€eyes€turned€up,€and€respiration€that€was€deep,€slow,€and€regular,€indicated€that€the€stage€ofÐ  Ðinsensitivity€to€pain€had€been€reached;€the€operation€should€not€begin€before€this€stage.ò òó ó€He€hadÐ Ýð Ðoften€observed€that€the€pulse,€which€was€generally€more€rapid€and€feeble€than€normal,€regainedÐ µ È Ðits€previous€strength€when€the€inhalation€was€discontinued.€He€believed,€based€on€clinicalÐ "   Ðepidemiological€observations,€that€the€cause€was€due€to€a€fault€in€his€apparatus.€Among€hisÐ e$x" Ðpatients€to€date,€children€ð ðinhaled€more€easily€than€the€adults€generally€did€.€.€.€[and]€were€moreÐ =&P!$ Ðquickly€affected,€generally€becoming€insensible€in€less€than€two€minutes,€and€always€without€anyÐ ((#& Ðof€the€struggling€which€sometimes€occurred€in€adultsðð€(540).€Since€used€the€same€inhaler,€theÐ í)%( Ðonly€difference€was€that€ð ðthe€tubes€were€wider€in€proportion€for€children€than€adultsðð€(540).Ð Å+Ø&* ÐShortly€before€submitting€the€manuscript,€he€had€disassembled€one€of€his€apparatus€and€foundÐ -°(, Ðthat€the€internal€width€of€the€tube,€supposed€to€be€five„eights€of€an€inch€throughout,€wasÐ í Ðsometimes€reduced€to€half€an€inch.€He€noted€that€ð ðI€am€now€getting€elastic€tubes,€valves€andÐ ÅØ Ðmouth„tubes,€made€purposely€for€the€apparatus€three€quarters€of€an€inch€in€diameter€.€.€.ðð€(541).Ô_Ô× ƒ„ ×Ý ƒ$ÓÝòòÚ  Ú67Ú  ÚóóÝ  Ý×  ×Ô_ÔÐ ° Ðò ò(Fig.€77)ó ó€The€editors€permitted€him€to€add€a€footnote€to€the€effect€that€the€wider€tubes€worked€asÐ u ˆ Ðexpected.€He€concluded€the€article€with€the€observation€ò ò(Fig.€78)ó ó€ð ðthat€I€am€inclined€to€look€uponÐ U h Ðthe€new€application€of€ether€as€the€most€valuable€discovery€in€medical€science€since€that€ofÐ 5H  Ðvaccinationðð€(541).€Ð    ÐÓ  Ó*€*€*Ð åø  ÐÓ5ÓIf€so,€Snow€had€done€more€than€anyone€else€to€make€it€happen.€ò òó óIn€the€first€month€of€1847,€he€hadÐ ½Ð Ðestablished€a€fundamental€anesthetic€principle€ð!ð€that€the€amount€of€ether€vapor€in€air€increasesÐ •¨ Ðwith€the€temperature€of€the€ether€ð!ð€and€put€it€in€practice€by€formulating€an€Ô_ÔSVPÔ_Ô€table€andÐ m€ Ðdesigning€an€apparatus,€by€virtue€of€which€he€could€select€and€control€the€amount€of€etherÐ EX Ðinhaled€by€patients€in€surgical€settings.€In€subsequent€weeks,€Snow€continued€this€three„stageÐ 0 Ðfeedback€loop€ð!ð€responding€to€clinical€problems€by€making€a€series€of€empirical€adjustments€inÐ õ Ðhis€apparatus,€engaging€in€additional€experimentation,€presenting€his€findings€at€the€WestminsterÐ Íà ÐMedical€Society,€and€finally€preparing€an€article€for€the€òòLondon€Medical€Gazetteóó€that€madeÐ ¥ ¸ Ðpublic€everything€he€had€done.€By€comparison,€James€Robinsonððs€òòTreatiseóó€on€ether,€which€hadÐ }"  Ðappeared€in€late€February,€was€anecdotal€and€self„congratulatory.€By€the€end€of€March,€JohnÐ U$h" ÐSnow€was€the€acknowledged€medical€authority€on€the€inhalation€of€ether,€and€RobinsonððsÐ -&@!$ Ðmeteoric€fame€was€eclipsed.€Snow€did€not€rest€on€these€laurels,€although€during€the€remainder€ofÐ (#& Ð1847€he€markedly€reduced€the€pace€of€research€while€serving€as€the€unofficial€spokesman€for€theÐ Ý)ð$( Ðnotion€that€anesthesia€should€be€a€branch€of€scientific€medicine.€Ð µ+È&* Ðà  àDavid€Ô_ÔZuckÔ_Ô€would€sum€up€as€follows:€In€this€òòÔ_ÔannusÔ_Ô€mirabilisóó€of€1847,€Snow€establishedÐ - (, Ðthe€practice€of€general€anesthesia€by€inhalation€on€a€sound€scientific€footing,€whereas€many€ofÐ í Ðhis€contemporaries,€including€Robinson,€approached€it€solely€as€an€empirical€art.× ƒÅ ×Ý ƒ$ÓÝòòÚ  Ú68Ú  ÚóóÝ  Ý×  ×€Inòòóó€addition,Ð ÅØ ÐSnow€set€an€agenda€for€research€into€the€pharmacology€of€anaesthetic€agents€that€was€so€far€inÐ ° Ðadvance€of€his€times,€that€after€his€death€in€1858€it€was€not€resumed€until€the€middle€of€the€nextÐ u ˆ Ðcentury.€I€agree.€Ð M ` Ðà  àBut€if€the€two€faces€of€the€Roman€god,€Janus,€is€a€metaphor€for€history,€I€myself€wouldÐ %8  Ðstress€the€face€that€looks€backward:€In€my€view,€it€was€Snowððs€good€fortune€that€ether€inhalationÐ ý  Ðjelled€with€his€prior€scientific€interests€and€medical€expertise€in€respiratory€physiology€andÐ Õè  Ðdiseases,€narcotics,€and€poisons.€His€rapid€and€successful€investigation€of€the€scientific€propertiesÐ ­À Ðand€clinical€applications€of€the€vapor€of€ether€in€1847€was€made€possible,€in€large€part,€becauseÐ …˜ Ðof€luck€and€Ô_ÔconsilienceÔ_Ô.à  àà h àà À àà  àÐ ]p ÐÓ  ÓÐ  5H ÐNotesÐ í ÐÌÓ  ÓÔCE.,US.,H©Ô