^, IMAGE EVALUATION TEST TARGET (MT-3) // .*" 1.0 ^K£ I2£ ut l&i 12.2 I.I u 114 Z 1^ 12.0 u WMU Photographic Sdsnces Corporation 23 WfST MAIN STRIET WIBSTIR.N.Y. 14SS0 (716)873-4303 CIHM/ICMH Microfiche Series. CIHM/iCIVIH Collection de microfiches. Canadian Institute for Historical Microreproductions / Institut Canadian da microraproductions historiqucs <\ Tachnical and Bibliographic Notaa/Notas tachniquaa at bibliographiquaa Tha Inatituta haa attamptad to obtain tha baat original copy avaiiabia for filming. Faaturaa of thia copy which may ba bibiiographicaily uniqua, which may altar any of tha imagaa in tha raproduction. or which may aignificantly changa tha uaual mathod of filming, ara chackad balow. L'Inatitut a microfilm^ la maillaur axamplaira qu'il lui a iti poaaibia da aa procurar. Las ditaiia da cat axamplaira qui sont paut-Atra uniquaa du point da vua bibliographiqua. qui pauvant modifiar una imaga raproduita. ou qui pauvant axigar una modification dana la mAthoda normala da filmaga aont indiqute ci-daasoua. □ Colourad covara/ Couvartura da coulaur I — I Covara damagad/ D n n D Couvartura andommagAa Covara raatorad and/or laminatad/ Couvartura raataurAa at/ou palliculte □ Covar titia miaaing/ La titra da couvartura manqua □ Colourad mapa/ Cartas gtegraphiquaa an couiaur Colourad inic (i.a. othar than blua or blacic)/ Encra da coulaur (i.a. autra qua blaua ou noira) I — I Colourad plataa and/or illuatrationa/ Planchas at/ou illuatrationa an coulaur Bound with othar matarial/ RaliA avac d'autraa documants Tight binding may cauaa shadowa or diatortion along intarior margin/ Lareliura sarria paut causar da I'ombra ou da la distorsion la long da !a marga IntAriaura Blanic laavas addad during rastoration may appaar within tha taxt. Whanavar possibla. thasa hava baan omittad from filming/ II aa paut qua cartainaa pagaa blanchaa ajoutiaa lors d'una raatauration apparaiaaant dana la taxta. mais. lorsqua caia itait possibla. caa pagaa n'ont paa 4tA filmAaa. |~n Colourad pagaa/ D D E D D D Pagaa da coulaur Pagaa damagad/ Pagas andommagtea Pagaa raatorad and/or laminatad/ Pagas raataurtaa at/ou palliculAas Pagaa diacolourad. stainad or foxad/ Pagas dicolorias. tachatias ou piquias Pagaa datachad/ Pagaa dttachias Showthrough/ Tranaparanca Quality of print varies/ Quaiit* inAgala da I'imprassion Includaa aupplamantary mataria!/ Comprand du matirial supplAmantaira □ Only adition avaiiabia/ Saula Mition disponibia Pagaa wholly or partially obscured by errata slips, tissues, etc.. hava been refilmed to ensure the best possible image/ Lea pagaa totalement ou partiellement obscurcies par un feuiilet d'errata. una pelure, etc.. ont At* filmies A nouveau da fa^on i obtanir la mailleure imaga possible. D Additional comments:/ Commentairea supplimentaires: This item is filmed at tha reduction ratio chaclced below/ Ce document est film* au taux da reduction indiqui ci-dassous. 10X 14X 18X 22X 26X 30X / I2X 16X 20X 24X 28X 32X Th« copy filmed h«ra hat b««n raproduesd thanks to tho gonorotity of: Mwlieal Library McGili Univanity MontTMi Tho imogos appoaring horo aro tho boat quality poaaiblo eonaidoring tho condition and tagibiUty of tho original copy and in kaaping with tho filming contract spaciflcationa. L'axamplaira fllmA f ut raproduit grico i la g4n4roalt4 do: MMlical Library MoQili Univartity IMontraal liaa imagaa auhrantaa ont 4ti roprodultoa avae la plua grand soin, compto tonu do la condition ot do la nottot* do I'oxomplairo film*, ot on GonformitA avac laa conditiona du contrat da filmago. Original capkM In printad papor covora ara fllmad beginning with tho front covor and anding on tho laat paga with a printad or illuatratod impraa- •ion, or tho bacic covor whon approprlata. All othor original coplaa ara filmad boginning on tho first paga with a printad or iiluatratad impraa- sion. and anding on tho laat paga with a printad or iiluatratad imprasston. Tha laat racordod frama on oach microficho shall contain tfw symbol — »> (mooning "CON- TINUED"), or tho symbol ▼ (mooning "END"), whichovor appliaa. Laa OKampiairaa originoux dont la couvorturo on poplar aat imprim4a sont filmte an common^ant par la pramior plat at an tarminant soit par la damiAra paga qui eomporto uno amprainti dimpraaalon ou dllluatration, soit par ia sacond plat, salon lo caa. Tous laa autraa axamplairaa originoux sont fiimte on common^ant par la pramlAra paga qui eomporto uno omprolnto dimproaaion ou dlllustration at w\ tarminant par la damlAro paga qui eomporto uno telle omprolnto. Un doe symbdos suh/ente apparaltra sur la demlAre image do cheque microfiehe, selon ie caa: ie symbde — »• signifie "A SUIVRE". Ie symbolo ▼ signifie "FIN". Mope, plates, charts, etc., mey bo filmed at different reduction retioe. Thoeo too lerge to be entirely included in one expoeure ere filmed beginning in tho upper left bond comer, left to right and top to bottom, aa many framee aa required. The following diegrama llluatrete the method: Lee cartee, plenchee, tabieeux. etc., pouvont Atre fiimAa i dee taux do rMuctlon diffAronts. Lorsque ie document est trop grand pour Atre reproduit en un soul cilchA, il est fiimA A pertir do I'angle aupArleur gauche, da jaucho A drolte, ot do heut en bee, en prenent Ie nombre d'imegea nAcesseire. Lee diegrammee suivants illustrent ia mAthode. 1 2 3 1 2 3 4 5 6 V Seprli!>t«d tm the Anthon fram the BRinsn Mbdioai. Journal, February 5tb, 1898. A QUAinilTATiyE METHOD OF SERUM DIA- GNOSIS BT ME4NS OF DRIED BLOOD. BT WYATT JOHNSTON, M.D., and HAROLD WOLFERSTAN THOMAS, M.D., Montreal. [From the Laboratory of the Montreal General Hospital.] WiDAL snggested^ the plan of simply dissolving the dried blood drop in a fixed nnmber of drops of water. Dacosta ad- vocates the same plan. The objection to this is that the previous volume of the blood drop cannot be determined after it has been dried, and they have not attempted to esti- mate the limit of possible dilation. The plan adopted by ns is that of taking the sample by means of a loop of standard size, made of No. 20 gauge copper wire, 2 mm. inside diameter. This gives a considerable quantity of blood which, when dried and spread on a elass slide, can afterwards be dissolved by means of a definite number of loopfuls of water. The solution thus obtained is abundant enough to yield much more blood solution th&a is necessary for quantitative measurement of the reaction. To ensure greater accuracy a small outfit was used in which the original loop used in taking the blood is returned, and em- ployed in nuking the dilutions. The dried blood drop is dissolved in five loopfuls of water used seriatim, the solution from eadi drop being sucked up by a capillary tube, and the whole mixed. From this stock solution standard sub-solutions are made in a stiaight capil- lary tube bound by a rubber band to a thermometer scale. The advantage of this plan is that the exact quantity of blood taken is immaterial. The tube is easily washed. The method of placing the loopfuls separately on the glass, as recommended by Deltoine, was found very reliable. In testing, a small platinum loop of the blood solutions is mixed with as many loops of water and bouillon culture as may be needed to give the required dilution, and make the volume of the diluted blood as nearly as possible equal to that of the culture. For convenience a table of the formulas for dilutions was made, and is useful when one is ascertain- ing the extreme limit of dilution possible, as this often reaches into the hundreds. 2 For an ordinary teat— to learn, for instance, if the blood reaotc at i to lo— all that is necessaiy is to mix a loop of the atook i to 5 solution with one of the cnltnre. By minng it with foor loops of water and five of oaltnre. a dilution of i to 50 is readily obtained. The time required when this simple test only is needed does not exceed five minutes. We have made duplicate observations to ascertain the aver* age limit of error, and find this to be about 10 per cent, aftei^ some familiarity has been obtained with the method. It is mu^ more accurate than a plan previously suggested by one of us of taking the standard of colour as a guide. Oomi>arative tests, when the duplicate samples consisted eittier of serum or ot watery solutions of fresh blood taken a J a Zeiss-Thoma barometer pipette, gave us results prac- cally identical with those by the dqr blood method, the latter being slightly lower, however, as a rule. So that if the dry blood showed a given intensity, the serum would show at least that, and perhaps 10 per cent. more. Drying for a few days did not make any great difference in Uie intensity, though it slightly lessened the reaction. We defer the publication in detail of our results until our ob- servations are more numerous. Hie result of the quantitative dry method so far has con- vinced us that it is delicate and accurate enough to give re- sults sufficiently close for practical purposes or for com- parison with otner methods of testing. It has not yet been foimd necessary to use the quantitative test for the ordinary routine diagnostic work ; but where the results are to be used lor recording doubtful or exceptional cases for scientific pub- lication, welhink quantitative data preferable. It does not appear necessary, however, to use quantitative teats in ordinary routine diagnostic work. Our experience has been that in no case hitherto examined by us have we been able to obtain a decisive reaction by the use of quantitative methods of fluid blood or serum, when it could not also be oblAined by the dried blood test wiUiout quantitative com- plioations. At the same time, we fully agree with the views expressed bsr Professor Welch on a recent occasion, that for scientific observations it was very desirable tliat the dried blood method should be also made a quantitative one, and our work in that direotion was prompted by a friendly suggestion coming from him, for which we wish here to express our thanks. bbfbbbncb. ^ Soo. 4e Biol., Januuy, i897« \