^ ,^^ ''«.^. IMAGE EVALUATION TEST TARGET (MT-3) y 1.0 1.1 U^ l&£ 12.2 14.0 US it I 2.0 m L25 II U 1 ,6 < 6" ► Photographic Sciences Cbrporation H3 WIST MAIN STRUT WEBSTER, N.Y. 14S80 (716)S72-4S03 ^ .« CIHM/ICMH Microfiche Series. CIHM/ICMH Collection de microfiches. Canadian Institute for Historical Microreproductions / Institut Canadian de microreproductions historiques Technical and Bibliographic Notaa/Notoa tachniquaa at bibliographiquaa Tha Inttituta has attamptad to obtain tha baat original copy availabia for filming. Paaturaa of thia copy which may ba bibiiographieaily uniqua, which may altar any of tha imagaa in the reproduction, or which may significantly change the usual method of filming, are checked below. D D D D Coloured covera/ Couverture de couleur r~1 Covers damaged/ Couverture endommagAe □ Covers restored and/or laminated/ Couverture restaurie et/ou pallicuiAe □ Cover title missing/ La titra de couverture manque n~| Coloured mapa/ Cartas gAographiques 1% couleur Coloured ink (i.e. other than blue or black)/ Encra de couleur (i.e. autre que bleue ou noire) I — I Coloured plates and/or illustrationa/ D Planchea et/ou illustrations en couleur Bound with other material/ Raiii avac d'autres documents Tight binding may cauae shadows or distortion along interior margin/ La re liure serrie peut causer de I'ombre ou de la distorsion ie long de la marge intArieure Blank leaves added during restoration may appear within the text. Whenever possible, these have been omitted from filming/ II se peut que certainea pages blanches ajoutAea lore d'una restauration apparaiaaant dana ie texte, maia. lorsque cela Atait possible, ces pagee n'ont pea Att filmiaa. 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Les ditails da cat axemplaire qui sont peut-Atre uniques du point de vue bibliogrephique. qui peuvent modifier una image reproduite, ou qui peuvent exiger une modification dans la mAthoda normaia de fiimaga aont indiqute ci-dassous. rn Coloured pages/ D Pagee de couleur Pagea damaged/ Pages endommagiaa Pages restored and/oi Pages restaurAea et/ou peiliculAes Pagea discoloured, stained or foxe« Pages dAcoiories. tachatias ou piqu6as Pages detached/ Pages dAtachtes Showthrough> Transparence Quality of prir Qualiti in^gaia da I'imprassion Includes supplementary materii Comprend du matiriai suppl^mentaira Only edition available/ Seule Mition disponibie r~~| Pagea damaged/ r~~l Pages restored and/or laminated/ rp\ Pagea discoloured, stained or foxec*/ r~1 Pages detached/ r~^ Showthrough/ I I Quality of print varies/ r~n Includes supplementary material/ I — I Only edition available/ Pages wholly or partially obscured by errata slips, tissues, etc.. have been raf limed to ensure tha best possible image/ Les pages totalement ou partieilement obscurcies par un fauiilet d'errata. una palure. etc.. ont M filmies A nouveau da faqon A obtenir la meilleure image possible. This item is filmed at tha reduction ratio checked below/ Ce document est film* au taux da reduction indiqu* ci-dessous. 10X 14X 18X 22X 26X 30X V 12X 16X aox 24X 28X 32X Th« copy fllm«d h«r« hat lM«n raproduead thanka to tha ganaroaity of: Medical Library McGiil Univaraity IMontraal Tha imagaa appaaring hara ara tha baat quality poaaibia conaidaring tha condition and iagibiiity of tha original copy and in Icaaping with tha fliming contract apaeifieationa. Original copiaa in printad papar covara ara fllmad baginnin<3 with tha front oovar and anding on tha laat paga with a printad or iiluatratad impraa- sion. or tha back eovar whan appropriata. All othar original copiaa ara filmad baginning on tha firat paga with a printad or iiluatratad impraa- •ion. and anding on tha laat paga wHh a printad or iiluatratad impraaaion. L'axamplaira ftlmA fut raproduit griea i la giniroaiti da: Madieai Library McGiil Univaraity Montraai Laa imagaa auhrantaa ont 4ti raproduitaa avac la plua grand aoln. compta tanu da !a condition at da la nattat* da raxamplaira filmA, at wt eonformit* avac laa conditiona du contrat da fllmaga. Laa axamplairaa origlnaux dont la couvartura •n papiar aat imprim^a sont fllmte an commandant par la pramlar plat at an tarmii>'> ;it aoit par la damlAra paga qui comporta una amprainta dimpraaaion ou dllluatration, aoit par la aacond plat, aalon la eaa. Toua laa autraa axamplairaa origlnaux aont fllm4a an comman^nt par la prami4ra paga qui comporta una amprainta dimpraaaion ou dllluatration at w% tarminant par la damlAra paga qui comporta una taila Tha laat racordad frama on aach mieroflcha ahall contain tha aymbol —^(moaning "CON- TINUED"), or tha symbol Y (maaning "END"), whichavar appliaa. Un daa aymbolaa suhranta apparaftra sur la damlAra imaga da chaqua mieroflcha, salon la eaa: la symbola -^ signifla "A SUIVRE". la aymbola ▼ signifla "RN". Mapa, piataa. charta. ate., may ba filmad at diffarant reduction ratioa. Thoaa too large to ba entirely included in ona expoaure are filmed beginning in tha upper left hand comer, left to right and top to bottom, aa many framee aa required. The following diagrama illuatrata the method: Lee cartea. planchea. tableaux, etc., pauvent Atra flimte i dee taux da rMuetion diffAranta. Loraque la document eet trop grand pour 4tre reproduit en un seul ciichA. il aat film* A partir da Tangle aupMeur gauche, de geucfie i droite. ec de heut en bee. an prenant la nombra dlmagea n4ceaaaira. Lea diagrammea auivants illuatrant la mMioda. 1 2 3 1 2 3 4 5 6 M •■ *i< i'! , '.( Beprlnted for the Authors from the Britisb Medical JouiurAii, February 6th, 1898. THS CONDITION OF TEST CULTURES ESPECIALLY AS BEOAbDS TITRATION FAVOURABLE TO CLEAR SERUM REACTIONS BY THE DRIED BLOOD METHOD. BT WYATT JOHNSTON, M.D., and D. D. McTAGGART. [From the Laboratory of the Board of Health of the Provinoe of Qnetiec.] Tms matter was referred to in the disoassion at Philadelphia on Jane 3rd, 1897, before the American Medi(»l Assooiation, by Bates Block and one of ns. We found that by vatying the composition of the mediam and the conditions under miich the cnltnre is kept, it is possible to obtain a culture which will yield excellent results or the reverse. We can now at will obtain a bouillon culture which cfin be left in contact with solutions of non-typhoid blood for 24 to 48 hours without giving any reaction, and will react promptly with typhoid blood. On the other hand, we can by neglecting certain details, get a test culture which will give one of two pseudo-reactions with almost any blood solution or serum, rseudo-reaction a is a decided clumping of over 95 per cent, of all the bacteria, but without loss of motion. Pseudo-reaction b culture with most blood solutions will show cessation of motion, with defective clumping. The former (a) we found to occur with cultures made very active by daily transplantations, and the latter (b) to growth in rather too alkaline bouillon. Our earliest observations happened to be made with bouillon giving satisfactory results. These became unsatisfactory for a few weeks under daily transplantations and good again on returning to monthly changes of stock cultures. After a few months a change in the laboratory peraonnel with different assignment of duties led to the second class of pseudo-reac* tions troubling us for a few weeks. Attention tolhe reaction of the culture medium remedied this difficulty, which seemed entirely due to a trifling increase in the alkalinity of the la- boratory bouillon. At another laboratory in charge of one of us there was still a supi)ly of bouillon remaining which gave satisfactory results. This reacted 3.5 per cent, acid to phenol- pthalein and just verged on the acid point with litmus. The adoption of tbouillons having a reaction requiring 3.5 per cent, of normal alkali to restore the tint of phenol-phthalein led to satisfactory results once more. The reading of the end point varies somewhat with the observer and the optimum reaction varies slightly with the particular culture and the composition of the medium, but always lies between 3 and 4 per cent. iJ ':■ ■ h The pscndO'reactions here described occur in bonillona giving a heavy growth and some sediment at the end ol twenty-foar honrs at 37° 0. They show a tendency to the spontaneous clamping mentioned by Widal, bat this is greatly exaggerated by adding blood solation. Seram does not have the same tendency to cause pseudo-reaction a. Dilution alone did not prove in our hands a satisfactory remedy. We believe that these anomalies explain the statements ol some writers that all serums tend to cause clumping sooner or later. The optimum reaction depends somewhat on the tem- Krature ol the thermostat and the age o! the culture. Satis* story cultures show gentle clouding only at twenty-lour hours, and have no pediment or serum, il the culture medium is made too acid it becomes insensitive, loses motility, and does not react promptly, but gives no pseudo-reaction. We note lor the first time in the British Mbdioai. JoxjbnaIi ol December 4th, 1897, that Del^pine had already in the Journal on April 17th, 1897. called attention to the danger ol pseudo-reactions il the bouillon is alkaline. He recommends neutral bouillon, whereas we lound acid bouillon prelerable. The question is one ol intensity of growth rather than of pure alkalinity alone, since the pseudo-reactions can also be avoided by raising the alkalinity till the growth becomes scanty. Per- sonally, our interest lay piore in deciding the most suitable reaction lor dried blood work. \h %, i i'. % r m (:■■ wWW HiMii ii CTlwW * -^ WW tw* i l l I Wlli ii fj^ i imiit'ifii I J-ff J- '^