128 MICROBIOLOGY 



still others for staining certain parts in the structure of the 

 bacteria, such as the flagella on the motile forms, the spores in 

 the spore-bearing organisms, and the capsules when present. 

 There are a large number of these special methods but those 

 ordinarily employed are as follows: 



Formulae for staining solutions. In the preparation of 

 nearly all of the staining solutions the saturated alcoholic 

 solution of the dye is employed. 



Saturated alcoholic solutions. The saturated alcoholic 

 solutions of the aniline dyes are prepared by pouring the dye 

 into a clean bottle and filling it about one-fourth full. Then 

 fill the bottle with strong (95% or absolute) alcohol, cork 

 tightly, shake, and allow it to stand for 24 hours. If at the 

 end of that time the dye is entirely dissolved, add more dye, 

 shake thoroughly, and allow it to stand for another day. 

 Repeat this procedure until there is a permanent sediment of 

 undissolved coloring matter in the bottom of the bottle. 



ALKALINE METHYLENE BLUE (LOEFFLER) 



Saturated alcoholic solution of methylene blue 6 cc. 

 Caustic potash (1% solution) 0.2 cc. 



Distilled water 20 cc. 



CARBOL FUCHSIN (zlEHL ? S SOLUTION) 



Fuchsin (dry) 1 gram 



Alcohol (absolute) 10 cc. 



Carbolic acid (5% solution) 100 cc. 



Dissolve the fuchsin in the alcohol, after which add the 

 carbolic acid solution. Instead of using the dry fuchsin and 

 alcohol, 11 cc. of a saturated alcoholic solution of fuchsin may 

 be used. If the mixture is not clear, add more of the satu- 

 rated alcoholic solution of fuchsin drop by drop until when 

 viewed through the pipette by transmitted light the liquid is 

 perfectly clear. 



ANILINE GENTIAN VIOLET (EHRLICH-WEIGERT) 



Saturated alcoholic solution of gentian violet 11 cc. 

 Absolute alcohol 10 cc. 



Aniline water 100 cc. 



