CONTRAST SCREENS 



267 



Transfer preparation from alcohol to A for 1 to 3 minutes. 

 Wash in alcohol, place in B for 3 minutes. Wash in alcohol, 

 place in C for 5 minutes. Dehydrate and clear as usual. 



In a section of animal tissues this stains most bacteria while 

 clearing the stain from the nuclei. 



Double Stain for Sporulating Bacteria 



Stain in hot carbol-fuchsine for 5 minutes. Decolourise in 

 5% acetic acid. Wash in water. 



Stain in Loffler's methylene blue. Spores remain red, 

 bacteria blue. 



Contrast Screens for Various Stains 



The following table from Wratten and Wainwright's 



Photomicrography gives the screens of the 

 suitable for use with various stains. 



M " series most 



For insects and yellow sections generally, photograph- 

 For contrast, with a C Screen ; 

 For detail in the section, with an F Screen. 



