SECTION TWO 



7. Cover the dried sections on the sHde with the leuco methylene 

 blue solution, which should be applied by means of a pipette. 



Note: If the solution becomes bluish it must be changed. 



8. Allow the staining solution to act until the section of the 

 normal tissue stains a distinct blue while that of the malignant 

 tissue remains colourless: this usually requires not more than 

 two to three minutes. 



9. Pour off the excess liquid. 



10. Rinse wdth a large volume of fresh, double-distilled water. 



11. Stain in solution B (acid fuchsin) for about two minutes, 

 taking care not to overstrain. 



12. Pour off excess stain; then dry sections thoroughly. 



13. Mount in glycerine, glycerine jelly or Aquamount, and 

 seal the edges of the coverslip with two coats of Laktoseal. Alter- 

 natively, sections may be mounted in Cristalite, Clearmount or 

 D.P.X., but Canada balsam is not to be recommended as in time 

 it will cause cancerous tissue to become blue. 



In examining the slides it should be borne in mind that bright 

 illumination may distort the staining effect of the leuco methylene 

 blue which is affected by light. 



Results: 



The nuclei of normal cells stain dark blue while the nuclear 

 structures are quite distinct. 



Nuclei of cancerous cells are said to remain almost colourless 

 or to assume a diffuse, hardly noticeable light blue or a slightly 

 perceptible pale pink. The nucleoli of malignant cells are said to 

 appear more intensely coloured than the almost colourless nuclei, 

 although their blue colour is far below that of normal nucleoli. 

 The cytoplasm of normal and malignant cells is stained distinctly 

 red by the acid fuchsin. The authors state that the conclusion is 

 indicated that in contrast to the nuclei or normal cells, those of 

 malignant cells are unable to transform the colourless hypo- 

 sulphite leuco base of methylene blue into the coloured form. 



Notes: 



(a) The authors, Roskin and Struve of the histological labor- 

 atory of M. Lomonossov University, Moscow, U.S.S.R., state 

 that the application of Unna's Rongaliteweiss for cytodiagnosis 



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