ISOLATION. 

 FIG. 126. 



273 



Hiss' plate media: small light colony (t) is composed of typhoid bacilli ; large 

 colony (c) of colon bacilli. (Hiss.) 



juice. Either litmus-paper or phenolphthalein may be used 

 to determine the reaction, which should be just perceptibly 



FIG. 127. 



Colony of typhoid bacilli highly magnified. (Hiss.) 



acid. The solution is then heated and 10 per cent, of nutri- 

 ent gelatin added, after which the medium is again neutralized 



18 Bact. 



