SECTION FOUR 



Results: 



Mitochondria are stained deep blue against a yellowish back- 

 ground. 



COTTON RED - METHYL VIOLET - ORANGE G 

 A cytological stain for plant tissues 



Solutions required: 



A. Cotton red i% aqueous. 



B. Methyl violet loB i% aqueous. 



C. Orange G - Clove oil. 



Technique: 



1. Stain sections of Flemming-fixed material in the cotton red 

 solution from eight to twenty-four hours. 



2. Wash v/ell in water ; then stain in the methyl-violet solution 

 from ten minutes to an hour according to the material. 



3. Pour off excess stain; then wash in water. 



4. Wash well with 95% alcohol; followed by thorough rinsing 

 with absolute alcohol. 



5. Drain well, and blot carefully. 



6. Immerse in orange G - clove oil from five to ten seconds. 



7. Pour off excess stain ; then wash the preparation with clove 

 oil. 



8. Differentiate in a fresh lot of clove oil for about one half to 

 one minute, controlling by examination under the microscope 

 until the violet stain is satisfactory. 



9. Pour off excess clove oil; then wash with three changes of 

 xylol. 



10. Mount in Canada balsam in xylol. 



Results: 



Metaphase and anaphase chromatin, red. Prophase chromatin, 

 violet. Chromoneata, red. Chromosome matrix, purple. Spindle 

 fibres and plastids, violet. Cytoplasm, light brownish grey. 

 Nucleoli, red. 



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