68 METHODS IN PLANT HISTOLOGY 



We are using a third method which seems to be better than either of 

 the two just described. Shdes can be run up, through the alcohols in 

 the usual way. 



C. Use the safranin solution described in B, but use clove oil solu- 

 tions of gentian violet and orange G, or gold orange. Make the orange 

 solution as described on page 65. The solution of gentian violet is 

 prepared in the same way, but it does not take as long to get a good 

 solution. 



After staining in safranin and dehydrating in absolute alcohol, flood 

 the slide with the clove oil solution of gentian violet or crystal violet 

 and stain for 5-30 minutes, or even for hours if necessary. Drain the 

 stain into the bottle, for it can be used repeatedly. Put pure clove oil 

 on with a pipette and watch until the stain is satisfactory. In a mitotic 

 figure, the chromosomes should be red, and the spindle, violet. Pour 

 off the clove oil and put on the orange. About 10-30 seconds will usu- 

 ally be long enough. Pour the orange back into its bottle, rinse with 

 pure clove oil, and place the slide in a Stender dish of xylol. This xylol 

 will soon take on an amber color. Transfer to clear xylol and mount in 

 balsam. 



With freehand sections, which are likely to be much thicker, the 

 process is the same but the times will be longer. 



Safranin and light green. — Stain in 50 per cent alcoholic safranin, 

 wash in 50 per cent alcohol, but stop while the safranin is still some- 

 what stronger than desired in the finished mount ; then stain in light 

 green (1 g. in 100 c.c. of 90 per cent alcohol) for 10-30 seconds. The 

 light green not only stains vigorously but reduces the safranin. Pass 

 through 95 and 100 per cent alcohol, clear in xylol, and mount in 

 balsam. 



The light green can be dissolved in clove oil. With a pipette, flood 

 the slide with light green, stain for 30 seconds, pour the light green 

 back into its bottle, rinse with pure clove oil, transfer to xylol, and 

 mount in balsam. 



Used in either way, this combination is very good for anatomical 

 work, especially for vascular anatomy. 



Cyanin and erythrosin. — Both solutions may be made according to 

 the general formula for anilins, or 1 per cent aqueous solutions may be 

 used. Miss Thomas recommends 1 gram dissolved in 100 c.c. of 95 per 

 cent alcohol. After the solution is complete, add 100 c.c. of distilled 

 water. Since the combination is used only for paraffin sections or for 



