STAINING, PRACTICAL AND THEORETICAL 



(b) Haematoxylin and eosin, or a safranin counterstain may be 

 employed between steps 5 and 6. 



(c) For more detailed information readers should consult the 

 original paper which shows two photomicrographs. 



Reference: Fullmer, H. M. & Lillie, R. D. (1956). 



OSMIC ACID 

 For demonstrating the interstitial cells of the testis 



Solutions required: 



A . Champy's fluid 



Osmic acid, 2% . . . . • • 4 volumes 



Potassium dichromate, 3% • • 7 volumes 

 Chromium trioxide, 1% • • 7 volumes 



B. Pyroligneous acid . . . . i volume 

 Chromium trioxide, 1% . . 2 volumes 



C. Potassium dichromate, 3% 



Technique: 



1. Fix small pieces of tissue in solution A for twenty-four hours. 



2. Wash in distilled water for half an hour. 



3. Immerse in solution B for twenty hours. 



4. Immerse in solution C for three days at 37° C, changing 

 the solution every twenty-four hours. 



5. Wash in running water for twelve to twenty-four hours. 



6. Dehydrate; clear; embed in paraffin wax. 



7. Cut sections 5)U, in thickness and fix them to slides. 



8. Dewax with xylol, and carry through the usual descending 

 grades of alcohol to distilled water. 



9. Mount in Farrants' medium, Aquamount or glycerine jelly. 



Results: 



Interstitial cells: conspicuous black granules of varying size in 

 the cytoplasm. Remainder of testis : yellow. 



336 



