COLON BACILLUS TEST lOI 



Solution No. I 



Para-dimethyl-amido-benzaldehyde 4 parts 



Absolute alcohol 380 parts 



Concentrated HCl So parts 



Solution No. II 

 Sat. sol. of potassium persulphate. 



The indol test is performed as follows : Add 5 cc. of solution I 

 to 10 cc. of a broth culture and then add 5 cc. of solution II, the 



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 ' ■.; •'' '.■ / ■. ■:■■■' • '■■'■■" : . 







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Fig. 28. — Bacillus of typhoid fever, stained by Loeffler's method to show flagella 

 (X 1000). — {Williams.) 



whole being then shaken. A red color indicates indol. Some of 

 the leading bacteriologists consider this a very valuable test. 



The so-called hog cholera group or the Gaertner group of bacilli 

 is important from the standpoint of the food bacteriologist. The 

 Gaertner group occupy a position intermediate between the 

 chemically active coli group and the chemically inert typhoid 

 group and includes the following important species or rather strains 

 — the Bacillus enteritidis strain which includes many of the bacteria 

 isolated in cases of food poisoning and some of the B. typhi murium 



