SPECIAL METHODS. l8/ 



color are still rising, the objects are placed in neutral absolute 

 alcohol, and, after the repeated renewal of this, in clove-oil 

 or bergamot-oil, which still extracts light clouds of color, 

 and finally mounted in balsam. The difficulty of this 

 method consists in determining the right minute when the 

 objects in alcohol and in oil are neither too much nor too 

 little washed out. 



In successful preparations the chromatin will be purple- 

 red, the threads of the achromatic spindle gray-brown, gray, 

 or violet, the centrosomes (cf. 3483) the same or light 

 reddish. 



324. I have tested the last two methods upon the root- 

 tips of Vicia Faba and on various other vegetable objects 

 and can most heartily recommend them for staining vege- 

 table nuclei. I obtained the most instructive preparations 

 by leaving the sections (I worked with microtome sections) 

 from J to 2 hours in Hermann's aniline-water-safranin. I 

 then washed them successively in acid alcohol and in alcohol, 

 added aniline-water-gentian-violet, which I left on the sec- 

 tions for 2 to 4 minutes at most, washed off the dye with 

 water, immersed them for 5 minutes or longer in Gram's, 

 iodine solution, and then washed either with alcohol or suc- 

 cessively with alcohol and clove-oil, and mounted in Canada 

 balsam ; or I also subsequently stained with orange. In the: 

 latter case I washed the sections, after they came from gen- 

 tian violet, but a very short time in alcohol and then placed 

 them in a concentrated aqueous solution of orange, which 

 was allowed to act a few minutes, then washed them inr 

 alcohol and transferred, in the usual way, to Canada balsam. 



In good preparations where orange was used, the nucleolii 

 and the karyokinetic figures from aster to dyaster were deep 

 red, the nuclear framework of resting nuclei and the spirem 

 and dispirem were violet or blue, the achromatic nuclear 

 figure and the cytoplasm were yellow-brown. 



[Gjurasin has used these methods with much success, after 

 many others had failed, for bringing out the karyokinetic 

 figures in the asci of Peziza, after the material had been 

 fixed for two days in Flemming's chrom-osmic-acetic acid.J 



