188 



IM-'i:("l'IVE ni.SKA.SKH. 



(Ill the si.liitioii fill- ti'ii iiiiliiitcs to li-ilf ;iii lioui', tliiMi ti^ii sfnr tliclu 

 t(j loiliiic-potiissic-iodide w.liit ion, nut il t licy ;issiimo tin- coloin- ot a 

 ten lent; tlicii iimiHTSH tliciii in ;il''oliol nntil tli.'.v ;nv a.^coloriswl ; 

 (Up t]i(-m in an .-ilcoliolic solution of cosin toi- a, few nioiiicnts, and 

 then ti-aiistpi- thoii to clove oil to clai'ify tlio lilm ; to i'ciiio\c tlio 

 clove oil K'-Mitly press the cover Ijetween two layers of clean liltei' 

 pa,[)er, then iiioiiiit in xylol balsam. 



A e-ood method for cniti vatin,!,' streptococci is to eiiiiiloy a, steril- 

 ised loope(l platinum wire, and to spread a droplet, for example, of 

 [aisor hlood, over(Jiesurfac(. of nutrient apir-aear.-.didiliedohlirpiely. 



Fid. '.III. — STrj-;i"rococcus PvoiaiXKs liovis. Pnre-cnltures on nntiie-nt 



gelatine. 



", Sub-cultiir(^ frijni aj^^ar. I>, Suh-ialtnn- frntii Ijretli. 



';, Siib-onlture from milk. fl, Stil>-ciiltare fi'ijni milk. 



The tubes are then placed in the incubat(.)r at -37^ C ; the strepto- 

 cocci will ap[iear in the course of two or three days in the form 

 of minute dotted colonies. If present alone, and in considerable 

 ([uantifies, the inoculated sui'faoe will exhibit a pure cultivation 

 consisting of a number of such colonies, whilst a flocculent ma.ss is 

 observed in the li(juid whi'di collects at the bottom of aLrar-atrar 

 tubes; this flocculent mass will Vie found to be comp(j.se(l of chains. 

 From such a tube inoculate a uumbc-r of the small flasks employed 

 in Pasteur's laboratory for cultivations in liipiids. In this way 

 a number of [lure-cultivations in milk and broth ai'C established, 

 which can l.e j'e idily examim^d from time to time. From a. pure- 



