22 MATERIALS AND PROCESSES OF SLIDE-MAKING 



Johansen's Safranin: 

 Staining solution 



Methyl cellosolve 50 ml. 



95% Alcohol 25 ml. 



Water 25 ml. 



Sodium acetate 1 Gm. 



40% Formaldehyde 2 ml. 



Safranin 0.1 Gm. 



Note: Dissolve the dye in the methyl cellosolve. Then add the alcohol. Dis- 

 solve the sodium acetate in the formaldehyde and water and add these to the 

 dye solution. 



Differentiating solution 



Identical with that used with Regaud's hematoxylin (see page 16). 

 STAIN IS USED ON ANIMAL TISSUES AS FOLLOWS: 



1. Accumulate the sections in water. 



2. Transfer the sections to stain and let them remain there from 24 to 48 

 hours (or even longer) until the nuclei are darkly stained. 



3. Dip the slide up and down in the differentiating solution until the un- 

 wanted stain has been removed from the cytoplasm. 



4. Wash it in running water to remove the picric acid. 



5. Mount the section in the usual manner. 



The stain given below is the basis for about 90 per cent of all bacteri- 

 ological techniques: 



Ziehl's Carbolmagenta: 

 Staining solution 

 Grind together 1 Gm. of magenta ("basic fuchsin") with 10 ml. of 90 

 per cent alcohol and 10 Gm. of phenol. When this mixture has been 

 reduced to a paste, take 100 ml. of water and rinse out the mortar, using 

 10 successive 10-ml. batches. These batches should be accumulated, left 

 a few hours, and then filtered. 

 The use of this stain for bacteria is described on page 104. If it is to be used 

 for staining nuclei in either animal or plant sections, it is necessary only to 

 transfer the section from water to the stain for 10 to 20 minutes and then to 

 differentiate as long as is required with 1 per cent acetic acid. 



It is sometimes necessary to stain bacteria blue, either as a contrast to the 

 red color produced by Ziehl's solution or in order to differentiate bacteria 

 which have been decolorized. Much the best solution for this purpose is: 



Lillie's Ammonium Oxalate Crystal Violet: 



Note: This solution is often called "Hucker's ammonium oxalate crystal 

 violet or Hucker-Conn crystal violet." 

 Staining solution 



Dissolve 2 Gm. of crystal violet in 20 ml. of 95 per cent alcohol. Dis- 



