STAINS AND STAINING 
55 
Many anilins stain quite deeply in 1 to 20 minutes, but if the 
stain washes out during the dehydrating process, stain longer, even 
10 to 24 hours if necessary. Often the brilliancy of the stain can be 
increased by leaving the slide for 5 minutes in a 1 per cent solution of 
permanganate of potassium before staining. The permanganate acts 
as a mordant. 
The following are the more important anilins now in use by botan¬ 
ists. The directions apply to solutions made up according to the 
formulas given with the different stains. 
Safranin. — Two safranins are sold by dealers, one soluble in 
water and the other soluble in alcohol. The alcoholic is somewhat 
soluble in water and the aqueous is somewhat soluble in alcohol, but 
both make better solutions when used with their intended solvents. 
The best aqueous solution is simply a 1 per cent solution in 
distilled water. 
The alcoholic solution is made by dissolving 1 g. of the alcoholic 
safranin in 100 c.c. of 95 per cent or absolute alcohol and, after the 
1 safranin is completely dissolved, adding 50 c.c. of distilled water. 
According to Flemming, dissolve 0.5 g. of alcoholic safranin in 
50 c.c. of absolute alcohol, and after 4 days add 10 c.c. of distilled 
water. 
A method which we have used for many years with good results 
is to make a 1 per cent solution of the aqueous safranin in distilled 
water; then make a 1 per cent solution of the alcoholic safranin in 
95 per cent alcohol; then mix equal volumes of the two solutions. 
This makes a strong solution of safranin in about 50 per cent alcohol. 
The first American safranins were very unsatisfactory but there 
have been great improvements and one company, the National 
Anilin and Chemical Company, has produced a safranin with 90 per 
cent dye content, much stronger than any of the European stains. 
This is the safranin which has been certified by the Committee on 
Standardization of Stains. Other companies are also improving. 
Coleman and Bell's Safranin Y, for bacilli, is good for staining xylem. 
All safranins keep indefinitely, solutions 20 years old staining 
as well, or better, than when fresh. 
An anilin safranin may be made according to the general formula. 
The transfer to the stain depends upon the formula. If the stain 
is aqueous, transfer to the stain from water; if made up according to 
the general anilin oil formula, transfer to the stain from water or, 
