MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



all excellent fluorochromes for fat, while berberine sulphate is 

 much used for protozoal parasites, particularly for malaria. Thio- 

 flavine has been found satisfactory for virus and for bacteria, as 

 well as for general fluorochromic staining, while acriflavine has 

 been used for trypanosomes and as a general stain, and uranin is 

 one of the most suitable fluorochromes for intravital staining. All 

 these fluorochromes are used in very dilute aqueous solutions, 

 that is to say, something to the order of o-i to o-oi per cent. 



I. Differential Staining of C3rtoplasni, Nuclei, Nucleoli 



and Chromatin 



Solutions required: 



A. Congo red o-i% aqueous or acid 



fuchsin 0'i% aqueous. 



B. Acridine yellow Hi 07 o-i% 



aqueous or coriphosphine o-i% 

 aqueous. 



Technique: 



1. Sections are stained for two minutes with the Congo red or 

 acid fuchsin solution. 



2. Pour off excess Congo red ; then stain for two minutes with 

 the acridine yellow or coriphosphine solution. 



This technique gives a very sharp differentiation. 



2. Staining of Fat 



Method A. Solution required: 



Phosphine 3R o-i% aqueous, or 

 methylene blue 1% aqueous. 



Technique: 



1. Stain frozen section for two minutes ; then rinse in water. 



2. Examine in water. 



Results: 



With phosphine 3R fat is observed as a silver fluorescence 



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