24 LABORATORY BACTERIOLOGY 



35. Formulae for Staining Solutions. — The dyes here used 

 are methylene-blue, gentian- violet, methyl-violet, and basic 

 fuchsin. For the other dyes see text-books. 



ALKALINE METHYLENE-BLUE (LOEFFLER'S) 



Saturated alcoholic solution of methylene-blue . 30 c.c. 

 Caustic potash i % solution ... . . i c.c. 

 Distilled water 100 c.c. 



The saturated alcoholic solution of the methylene-blue (or 

 of any of the dyes) is 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, 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. Then label. (The saturated solution 

 will be kept in stock in the laboratory.) 



CARBOL FUCHSIN (zIEHL'S SOLUTION) 



Fuchsin (dry) I gram. 



Alcohol (absolute) 10 c.c. 



Carbolic acid, ; % solution . . 100 c.c. 



Dissolve the fuchsin in the alcohol, after which add the car- 

 bolic acid solution. Instead of using the dry fuchsin and alco- 

 hol, II c.c. of a saturated alcoholic solution of fuchsin may be 

 used. 



It is more convenient for each student to prepare the fol- 

 lowing : — 



Saturated alcoholic solution of fuchsin .... 2.50.0. 

 Carbolic acid, 5 % solution 20 c.c. 



ANILINE METHYL-VIOLET (EHRLICH-WEIGERT) 



Saturated alcoholic solution of methyl-violet . . 11 c.c. 



Absolute alcohol . " 10 c.c. 



Aniline water 100 c c. 



