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COLLOIDS IN BIOLOGY AND MEDICINE 



1 Loffler's blue is a methylene blue solution with a trace of alkali; Carbol-fuchsin is a fuchsin solu- 

 tion containing phenol. Both of these as well as Gram's stain are employed in staining bacteria. 

 The latter affords an opportunity for the differentiation of certain bacteria and cocci. Although 

 many bacteria are entirely or partly decolorized by subsequent treatment with the iodin-potassiuna 

 iodid solution and washing with alcohol, many retain their stain. 



