118 Biological Stains 



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WAVELENGTH Tn }X 



Fig. 13. Spectral curves of three oxazin dyes: 

 1. Brilliant cresyl blue. 2. Nile blue sulfate. 3. Resazurin. 



staining it has special value because of its properties as an indicator 

 of oxidation-reduction. Of recent years it has been employed for 

 numerous purposes: staining protozoa, nematodes; in animal 

 cytology; and as an amebicide. Its best known use, however, is 

 as a blood stain to bring out reticulated cells and platelets. A well- 

 tried procedure is that of Cunningham (1920), as modified by 

 Isaacs {in McClung, 1937, p. 319); a somewhat different technic is 

 that of Robertson (1917) for counting reticulated cells, and that of 

 Buckman and Hallisey (1921) for platelets. 



Of recent vears some interest has been aroused bv observations 

 that certain derivatives of brilliant cresyl blue stain tumor cells 

 selectively and retard the growth of tumors. See Lewis, Sloviter 

 and Goland (1946). The relation between ability to stain and to 

 retard growth is very interesting, even if not of practical signifi- 

 cance. 



For technic of Cunningham's method of staining reticulated corpuscles and 

 platelets see Staining Procedures, p. ID3-8. 



For technic of Robertsons' method for counting reticulated corpuscles, see Id. 

 p. ID3-8. 



