5-11 THE YEAST CELL 



d. Mordant in iodine solution (1% iodine plus 1%KI in 80% 

 alcohol), 20 minutes. 



e. Distilled water, rinse. 



f . Stain in 1% aqueous crystal violet that has been brought 

 to a boil and filtered, 20 minutes. 



g. Tap H2O, rinse. 



h. Distilled H2O, rinse, 

 i. 70% alcohol, 2 minutes. 



j. Anilin blue in 95% alcohol (enough to color alcohol faint- 

 ly), 2-5 minutes, 

 k. Dehydrate in absolute alcohol, clear, toluene, mount. 

 Results: Chromosomes - deep purple 

 Centrosome - pale blue 

 Nucleolus - pale blue 

 Cytoplasm - pale blue 



6. Heidenhain's hematoxylin. 



a. Fixation, 8-10 minutes. 



b. Tap H20,wash, 10-15 minutes. 



c. Mordant in fresh 4% ferric alum, 3-4 hours. 



d. Tap water wash, 5-10 minutes. 



e. Distilled water, rinse. 



f. Stain in hematoxylin, 4 hours. 



g. Tap water, rinse thoroughly. 



h. Destain in 2% aqueous ferric alum or in picric acid, 



which is more painstaking but gives good results, 

 i. Tap water wash, 20 minutes, 

 j. Dehydrate in 70%, 95% alcohols, clear, 



2 changes of toluene, moimt in neutral damar. 

 Results: Chromosomes - black 



Centrosome- blue-black 

 Nucleolus - blue -black 

 Cytoplasm - gray or colorless. 



7. Giemsa. 



a. Fixation, 8-10 minutes. 



b. Tap water wash, 10 minutes. 



c. Wash in 0.5% solution of sodium thiosulfate, 10 minutes. 



d. Distilled water, 3-5 minutes. 



e. Stain in 1-20 Giemsa -distilled H2O solution, 15-40 

 minutes. 



f. Distilled water, rinse. 



g. Dehydrate and clear in following acetone -toluene steps, 

 checking progress with microscope: (a) pure acetone 

 95 parts, toluene 5 parts; (b) acetone 70 parts, toluene 

 30 parts; (c) acetone 30 parts, toluene 70 parts, (d) pure 

 toluene; then mount in balsam. 



