MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



LEVADITI'S STAIN 

 For Treponema pallidum in sections 



Solutions required: 



A. Silver nitrate . . . . . . 2-5% aqueous 



B. Reducing solution: 



Pyrogallic acid . . . . • • 3 grn. 



Formalin . . . . . . • • 5 ml. 



Distilled water . . . . . . 100 ml. 



Technique: 



Tissues about i mm. thick should be fixed for twenty-four hours 

 in 10% formalin and embedded in paraffin wax after staining. 



1. After rinsing tissues in tap water, immerse in 95% alcohol 

 for twenty-four hours. 



2. Immerse in distilled water until the tissue sinks to the bottom 

 of the jar. 



3. Transfer to Solution A for 3 to 6 days at 37° C. in the dark, 

 changing the solution every twenty-four hours. 



4. Wash in distilled water; then immerse in Solution B for 

 twenty-four to seventy-two hours in the darkroom at room tem- 

 perature. 



5. Wash in distilled water; then dehydrate with 80%, 95%, 

 and absolute, alcohol. 



6. Clear in cedarwood oil and embed in paraffin wax. 



7. Sections are cut 5/^ in thickness and mounted after removal 

 of the paraffin wax. 



Results: 



Treponema, jet black. Tissue, yellow to brown. 



LIGHT GREEN - ACID FUCHSIN (Alzheimer) 

 For demonstrating neuroglia changes 



Solutions required: 



A. Osmic acid 2% aqueous . . 20 ml. 



Chromic acid 1% aqueous . . 75 ml. 



Glacial acetic acid . . . . 0-5 ml. 



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