TRIPLE-STAINED SECTION OF TONGUE 127 



formula cited (2 to 10 minutes) will be found to cover the range normally 

 necessary. 



A slight difficulty will be occasioned in dehydration through the tendency 

 of the picric acid to leave the tissues in the various alcohols employed. Either 

 this may be prevented by dehydrating in a series of 1 per cent solutions of 

 picric acid in the various alcohols, or it may be ignored completely according 

 to the depth of yellow color which is to be retained. If on the contrary, a very 

 pale yellow is desired, the sections may have to be put in 96 per cent alcohol, 

 for a period of time beyond that necessary for dehydration, to remove the un- 

 wanted picric acid. Then the sections are cleared in xylene in the normal man- 

 ner and mounted in balsam. 



Summary 



1. Place a 5 -mm. slice of tongue in 100 ml. of Petrunkewitsch's fluid for 

 1 to 2 days. 



2. Wash overnight in running water. Dehydrate, clear, embed in low melting- 

 point wax, and cut 10 to 12- ^i sections. 



3. Flatten sections and squeeze to slide (see p. 69). Dry as rapidly as possible. 

 Dewax dried sections and grade down to water through usual reagents. 



4. Stain in celestin blue B until nuclei are deeply stained (5 minutes to 1 hour). 

 Overstaining is not possible. 



5. Rinse in water and stain in van Gieson's picro-acid-fuchsin from 2 to 10 

 minutes. 



6. Dehydrate and diffisrentiate in 95 per cent alcohol. Clear and mount in the 

 usual way. 



