IMAGE EVALUATION TEST TARGET (MT-S) 1.0 1.1 La 12.8 no i^^" us 1^ 112 a i2.0 L25 III 1.4 i i(.8 mam III 1.6 ^V/ ^"« Photographic Sdences Corporation SJ \ iV N> ' ^s^ °:^k ^?Lk. 23 WEST MAIN STREET WEBSTER, N.Y. 14580 (716) 872-4503 4r CIHM/ICMH Microfiche Series. CIHM/ICMH Collection de microfiches. Canedian Institute for Historical Microreproductions / Institut Canadian de microreproductions historiques C^ Technical and Bibliographic Notas/Notas tachniquaa at bibliographiquaa Tha inttituta has attamptad to obtain tha baat original copy availabia for filming. Faaturas of thia copy which may ba bibiiographically uniqua. which may altar any of tha imagaa in tha raproduction. or which may significantly changa tha uauai mathod of filming, ara chackad balow. □ Colourad covars/ Couvartura da coulaur I — I Covars damagad/ Couvartura andommagAa □ Covars rastorad and/or laminatad/ Couvartura raatauria at'ou pallieulAa I — I Covar titia missing/ D D D D D La titra da couvartura manqua Colourad mapa/ Cartas giographiquas an coulaur Colourad inic (i.a. othar than blua or black!/ Encra da coulaur (i.a. autra qua blaua ou noira) nn Colourad plataa and/or iiluatrations/ D Planchas at/ou illustrations an coulaur Bound with othar matarial/ Raiii avac d'autras documants Tight binding may causa shadows or distortion along intarior margin/ La r^ liura sarr^ paut causar da I'ombra ou da la distorsion la long da la marge intiriaure Blank laavas addad during rastoration may appaar within tha taxt. Whana*«ar possibla. thasa hava baan omittad from filming/ II sa paut qua cartainaa pagaa blanchaa ajouttes lors d'una rastauration apparaiauant dans la taxta, mais, lorsqua cala Atait possibla, cas pagas n'ont paa «t« film^as. Additional commants:/ Commantairas supplAmantairas: L'Instltut a microfilmi l« maillaur axamplaira qu'ii lui a At* possibla da sa procurar. Las ditaiis da cat axamplaira qui sont paut-Atra uniquas du point da vua bibllographiqua, qui pauvant modifiar una imaga raproduita, ou qui pauvant axigar una modification dans la mAthoda normala da filmaga sont ind!qu4s ci-dassous. □ Colourad pagas/ Pagaa D This itam is filmad at tha reduction ratio chackad balow/ Ca document ast film* au taux da reduction indiqui ci-dassous. Pagaa da coulaur Pagaa damaged/ Pagas andommagias Pages restored and/oi Pagas reataurtes at/ou palliculies Pagaa discoloured, stained or foxei Pages dAcolories, tachetAes ou piquies Pagas detached/ Pagas d^tachtes Showthroughy Transparence Quality of prir Quaiiti inigale de I'impression Includes supplementary matarii Comprend du matiriel suppMmentaire Only edition evailabia/ Seuie Mition disponibie pn Pagaa damaged/ r~~] Pages restored and/or laminated/ rr*] Pagaa discoloured, stained or foxed/ r~n Pagas detached/ r~n Showthrough/ rn Quality of print varies/ |~~| Includes supplementary material/ I — I Only edition evailabia/ Pages wholly or psrtially obscured by errata slips, tissues, etc., have been refiimed to ensure the best possible Image/ Les pages totalement ou partiallemant obscurcies par un feuillet d'errata, une pelure, etc.. ont Att filmtes A nouveau de fapon i obtenir la meiileure imaga possibla. 10X 14X 18X 22X 26X 30X y 12X 16X aox 24X 28X 32X "^.^JfWKp^ Th« copy film«d h«r« Hm lM«n raproduetd thanks to th« g«n«rosity of: WMieal Library MoQill Univmity Montraal Tho imagos appaaring hara ara tha baat quality poaalbia considaring tha condition and lagibllity of tha originai copy and in icaaping with tha Aiming contract spaeif icationa. L'axampiaira flimA fut raproduK grica i la g^niroaiti da: MMlical Library McGill UnivarsHy Montraal Laa tmagaa sulvantaa ont M raprodultaa avac ia plua grand soin. eompta tanu da ia condition at da ia nattatA da l'axampiaira fllm4. at an eonformit* avac laa condltiona du contrat da fllmaga. Originai copias in printad papar eovara ara filmad baginning with tha front covar and anding on tha last paga with a printad or iiluatratad impraa- sion, or tha bacic covar whan approprlata. All othar originai coplaa ara filmad baginning on tha first paga with a printad or iiluatratad impraa-. sion, and anding on tha laat paga with a printad or iiluatratad impraaalon. Laa axamplairaa orlginaux dont la couvartura an paplar aat imprimte sont flimte an commandant par ia pramiar plat at an tarmlnant soit par ia damiira paga qui comporta urn amprainta d'Impraaaion ou dlHustration, soit par ia sacond plat, salon la caa. Tous laa autraa axamplairaa orlginaux sont fiimis an commanpant par la pramlAra paga qui comporta una amprainta dimpraaalon ou d'iiiuatration at an tarmlnant par la damlAra paga qui comporta una taila amprainta. Tha last racordad frama on aach mieroflcha shall contain tha symbol —i»>( moaning "CON- TINUED"), or tha symbol y (moaning "END"), whichavar appiiaa. Un daa symbolaa sulvanta apparaftra sur ia damlAra imaga da chaqua mieroflcha, salon ia ea«: la symbola — »> signifia "A SUIVRE", ia aymboia ▼ signifia "FIN". IMapa, plataa, charts, ate, may ba filmad at diffarant raduction ratios. Thoaa too iarga to ba antlraiy included in ona axposura ara filmad baginning in tha uppar iaft hand comar, iaft to right and top to bottom, aa many framaa aa raquirad. Tha following dlagrama illuatrata tha mathod: Laa cartaa, planchaa. tableaux, ate, pauvant Atra filmAa i daa taux da rMuetlon diff4ranta. Loraqua la documant ««t trap grand pour Atra raproduit it un saui cllchA, il aat fllmA A partir da I'angia supArlaur gwucha, da gaucha A droita. • at da hiaut an baa. an pranant ia nombra d'Imagaa nAcassaira. Laa diagrammas suivants iilustrant ia mAthoda. 1 2 3 1 2 3 4 5 6 h [Reprinted from THE Medical News, September a8, 1895.] THE USE OF THE AUTOCLA¥E FOR STERI- LIZING NUTRIENT GELATIN. By WYATT JOHNSON, M.D., and J. E.' LABERGE, M.D., OF MONTREAL, CAN. [From the Laboratory of the Board of Health of the Province of Quebec,^ \ An impression seems to exist in many bacteriologic laboratories that the sterilization of nutrient gelatin by means of the autoclave is impracticable, owing to the tendency of this medium to lose its power of setting firmly when exposed to a temperature above the boil- ing point of water. Our experience has shown the con- trary to be the case, and the results obtained by a single sterilization in the autoclave have been fully as satis- factory as those obtained by fractional sterilization at 100° C. on successive days, so that we now employ the autoclave by preference to avoid delay and uncertainty. The steam -pressure employed is 3/4 of one atmosphere (equal to 115° C), saturated steam for fifteen minutes, after the gelatin has been filtered and filled into tubes. In a series of comparative tests in which half of the nutrient medium was prepared by fractional sterilization in an Arnold sterilizer, that prepared in the autoclave was equally transparent, retained the desired degree of alkalinity (usually 2 per cent, acid to phenolphthalein), and remained firm in plates or roll-tubes at a tempera- ture of from 24° to 25" C. In no case have we had any spontaneous growth in the tubes after this steriliza- tion. 9 We claim no priority for these observations, as the autoclave at 105" C. seems to have been employed for' some years in several French laboratories for sterilizing gelatin,^ though this fact does not appear to have be- come as generally known as it might be. In the labora- tory of the Board of Health of the Province of Quebec attention was first attracted by the fact that some gela- tin, sterilized in the autoclave through a mistake, re- tained its power of setting. In our experience a tem- pera':ure of ids'* C. has not always been sufficient to insure perfect sterilization. With reference to the temperature we employ, it may be well to mention that the test-tubes and small bottles which we use are made of very thick glass, so that the heat penetrates slowly. In working with thinner ones a lower pressure or a shorter time may be found to give the bestk-esult. We have employed gelatin giving a firm jelly, as considerable difference exists between the dif- ferent brands in respect to their melting-points. ite