STAINS AND STAINING 63 



tract the stain, without any appHcation of clove oil. The clove oil is 

 used, not only because it extracts the stain more slowly, but because 

 it dissolves the stain from some structures more rapidly than from 

 others; e.g., the stain may be completely removed from the chromo- 

 somes while it is still bright in the achromatic structures, so that with 

 safranin and gentian violet one can get red chromosomes on a violet 

 spindle. 



Many use the gentian violet dissolved in clove oil. Dissolve 1 g. 

 gentian violet in 200 c.c. absolute alcohol and pour into 200 c.c. of 

 clove oil. Stir thoroughly or shake in a bottle, then pour into an open 

 dish and keep warm until the mixture evaporates down to about 200 

 c.c. Then keep in a well-stoppered bottle. Put a little on the sHde with 

 a pipette, allow it to stain for 2-10 minutes and then drain back into 

 the bottle, for the stain can be used repeatedly. If gold orange or 

 orange G, dissolved in clove oil, is to be used, put it on at this point 

 and allow it to act for 10-20 seconds. Then drain it off into its bottle 

 and put the slide into a Stender dish of xylol. Transfer to a Stender 

 dish of clear xylol, and mount in balsam. 



Some still use cedar oil to follow the clove oil. This stops the action 

 of the clove oil, but the preparations harden slowly. 



Gentian violet or, better, crystal violet, is an excellent stain for 

 achromatic structures in all stages of development. Chromatin, in 

 many of its stages, is also stained. In metaphase and anaphase one 

 should be able to get red chromosomes and violet spindles with safra- 

 nin and gentian violet. If the chromosomes also persist in retaining 

 the violet, shorten the stain in gentian violet. Cilia stain well; starch 

 grains stain deeply, chromatophores less deeply, and Hgnified walls 

 may not stain at all. One should be able to get red lignified walls and 

 violet cellulose walls with safranin and gentian violet. 



Cyanin. — This stain is also called Quinolein blue and Chinolin blue. 

 Dissolve 1 g. of cyanin in 100 c.c. of 95 per cent alcohol and add 100 

 c.c. of water. The cyanin would not dissolve in 50 per cent alcohol. 

 We have not found Griibler's cyanin at all satisfactory with the fore- 

 going formula. With the general formula the Griibler's cyanin will not 

 dissolve. We use a cyanin prepared by H. A. Metz and Company, 122 

 Hudson Street, New York. This cyanin dissolves completely when 

 made up according to the general formula. It stains rapidly, 5-10 

 minutes usually being sufficient. Chromosomes take a deep blue, 

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



