STAINING, PRACTICAL AND THEORETICAL 



CRESYL FAST VIOLET 

 A chromatin test for the detection of chromosomal sex 



(After K. L. Moore, i960) 



Solutions required: 



A. Absolute alcohol \ equal 

 Ether j volumes 



B. Cresyl fast violet CNS . . . • i gm. 

 Alcohol, 50% 100 ml. 



Technique : 



1. Take scrapings, from the inside of the cheek, with a spatula. 



2. Spread the scraping on a slide. 



3. Fix immediately in the alcohol-ether mixture, for at least 

 fifteen minutes. 



Note: The author (Moore) states that the usual causes of poor 

 smears are: {a) not scraping firmly enough, with the result that 

 the number of cells obtained is insufficient, and (b) allowmg the 

 smear to dry before fixation, resulting in poor nuclear detail. 



4. Immerse the preparation in 70% alcohol for two minutes. 



5. Immerse in 50% alcohol for two minutes. 



6. Wash for one minute in each of two changes of distilled 

 water. 



7. Stain in the cresyl fast violet solution for seven to eight 

 minutes. 



8. Differentiate by dipping the slide quickly about five to seven 

 times in 95% alcohol. 



9. Dehydrate in absolute alcohol for one minute. 



10. Mount in Clearmount or Michrome mountant, or proceed 

 as follows: 



11. Wash in xylol. 



12. Mount in Clearmount or Michrome mountant or D.P.X. 

 or, if these are not available, in neutral Canada balsam in xylol, 

 although this is liable to cause fading of the stain. 



13. Examine under the oil immersion objective with a strong 

 source of light. 



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