70 METHODS IN PLANT HISTOLOGY 



For staining algae, more complete directions are given in chapter 

 viii. 



Acid fuchsin and iodine green mixtures. — Two solutions are kept 

 separate, since they do not retain their efficiency long after they are 



mixed : 



J Fuchsin acid . 1 g. 



\ Distilled water 50 . c.c. 



-r, j Iodine green . 1 g. 



\ Distilled water 50 . c.c. 



[ Absolute alcohol 100 . c.c. 



C ^ Glacial acetic acid 1.0 c.c. 



[ Iodine . 1 g. 



Mix equal parts of A and B. Transfer to the stain from water. The 

 proper time must be determined by experiment. For a trial, 24 hours 

 might be recommended. Transfer from the stain directly to solution 

 C and from C to xylol. 



A. Acid fuchsin . 5 g. in 100 c.c. of water 



B. Iodine green 0. 5 g. in 100 c.c. of water 



Mix a pipette full of A with a pipette full of B; stain 2-8 minutes; 

 transfer to 85 per cent or 95 per cent alcohol, dehydrate rapidly, clear in 

 xylol, and mount in balsam. Both these formulas are good for mitosis. 



Acid fuchsin and methyl green. — Both may be used in 1 per cent 

 aqueous solutions. 



For mitotic figures, stain in green for about an hour, wash in water 

 or alcohol until the green is extracted from the spindle, and then stain 

 for about 1 minute in the fuchsin. Dehydrate in 95 and 100 per cent 

 alcohol, clear in xylol or clove oil, and mount in balsam. If the green 

 washes out, stain longer; if it is not readily extracted from the spindle, 

 shorten the period. If the fuchsin stains the chromosomes, shorten the 

 period, and lengthen it if the fuchsin washes out from the spindle. The 

 chromosomes should take a brilliant green, and the spindle, a bright red. 



Delafield's haematoxylin and erythrosin. — Stain first in the haema- 

 toxylin, and after that stain is satisfactory, stain for 30 seconds or 1 

 minute in erythrosin. This is a good combination, and, for most plant 

 structures, gives a far better differentiation than the traditional hae- 

 matoxylin and eosin, since the erythrosin has all the advantages of the 

 eosin and is more transparent. Orange G is also a good stain to use 

 with Delafield's haematoxylin. 



