Stains and Staining 57 



alcohol. We have not found Griibler's cyanin very satisfactory with 

 the foregoing formula. With the general formula the Griibler's cyanin 

 will not dissolve. We use a cyanin prepared by H. A. Metz & Co., 

 122 Hudson Street, New York. This cyanin dissolves completely 

 when made up according to the general formula. It stains rapidly, 

 5 to 10 minutes usually being sufficient. Chromosomes take a deep 

 blue, but the spindle is only slightly affected. Lignified structures 

 stain blue, while cellulose walls are scarcely affected and the stain is 

 easily washed out. 



Iodine Green. Use a 1 per cent solution in 70 per cent alcohol. 

 Stain for an hour, rinse in 70 per cent alcohol, dehydrate in 95 per 

 cent alcohol and absolute alcohol, clear in xylol or clove oil, and 

 mount in balsam. If the stain washes out too rapidly and does not 

 give sufficient differentiation, stain longer, over night or even 24 

 hours. 



Lignified structures stain green, but, after proper washing, 

 cellulose is scarcely affected. A bright green may be left in the 

 chromosomes after all the stain has been washed out from the spindle. 



Acid fuchsin, erythrosin, and eosin are good contrast stains 

 for mitotic figures. Acid fuchsin or Delafield's haematoxylin are 

 good for cellulose walls. 



Light Green (Licht Grun). Light green is an acid stain, soluble 

 in water, alcohol, or clove oil. It stains quickly and forms a sharp 

 contrast with safranin or Magdala red. 



Stain in safranin and then, with little or no washing out, stain in 

 a weak alcoholic solution of acid green (about 0.2 g. in 100 c.c. of 

 95 per cent alcohol). From 20 seconds to about 1 minute may be 

 sufficient. The green rapidly reduces the safranin, and consequently 

 the staining must not be too prolonged. A successful preparation 

 should show red chromosomes and green spindle. Lignified walls 

 should be red and cellulose walls green. 



Malachite Green. A 1 to 3 per cent aqueous solution is good for 

 cellulose walls. The stain contrasts well with Congo red. 



Methyl Green. A 1 per cent solution in water is good for 

 staining lignified structures. Lee recommends that the solution 

 be acidulated with acetic acid. This is not necessary for staining 



