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SECTION TWO 



3. Stain in a freshly prepared, unfiltered, saturated solution of 

 Chlorazol Black in 70% alcohol for five to ten minutes. 



4. Drain off excess dye ; dehydrate ; clear in xylol and mount. 



Results: 



Embryo, epithelial cell tissues, outlined in black. Chromatin, 

 black. Nuclei, black. Muscle fibres, intense black. Lympho- 

 cytes, intense black. Blood cells, yellowish green. Cytoplasm, 

 greenish grey. 



Kidney and intestine, varying shades of green, grey and black. 

 Blood cells, light green. 



Nuclei and chromosomes are stained black; cytoplasm and 

 secreted products grey; chitin, green; glycogen, red. 



Notes: 



(a) Benzl alcohol may also be used as a solvent, in which case 

 results are somewhat different. 



{h) If it is desired to differentiate chlorazal black, dilute 

 Milton " (a proprietary antiseptic) may be used for the purpose. 

 {c) The stain may be incorporated with Lactophenol. 



CONGO RED 

 For Amyloid in tissues 



Solutions required: 



A. Congo Red 1% in distilled water. 



B. Lithium carbonate saturated aqueous 



C. Delafield or Ehrlich haematoxylin. 



Technique: 



1. Formalin or alcohol-fixed material may be embedded in 

 Celloidin or in paraffin wax, or frozen sections may be employed. 



2. Sections are mounted on slides and brought down to distilled 

 water as usual. 



3. Stain in the Congo Red solution for ten to thirty minutes. 



4. Immerse in the lithium carbonate solution for fifteen seconds. 



5. Decolorize in 80% alcohol until stain ceases to come away 

 in clouds. 



91 



