Two Difjereiit Stains on One Slide 425 



Restaining Faded Slides 



McCormick (1959A) Method 



Slides on long standing or if exposed to bright light frequently will 

 fade. If they must be recovered, McCormick offers the following method 

 to bleach them for restaining. 



procedure: 



1. Remove cover glass by soaking slides in xylene until cover glass 

 slips off. Do not force it off; the sections might get torn. 



2. Soak longer in xylene to make certain that all of the resin is re- 

 moved. 



3. Hydrate to water. 



4. Treat with 0.5% potassium permanganate (0.5 gm./lOO ml. wa- 

 ter): 5 minutes. 



5. Wash in running water: 5 minutes. 



6. Bleach with 0.5% oxalic acid (0.5 gm./lOO ml. water) until color- 

 less: 1-2 minutes. If old stain still remains, repeat steps 4, 5 and 6. 



7. Wash thoroughly in running water: 5 or more miniues. 



8. Restain, using more-dikue stains or for a shorter time. Potassium 

 permanganate and oxalic acid make tissues especially sensitive to 

 hematoxylin and aniline nuclear stains. 



Two Different Stains on One Slide 



Feder and Sidman (1957) Method 



This method can be used advantageously when it expedites a quick 

 checking of a tissue against two stains, side by side. 



procedure: 



1. Hydrate sections to water. 



2. Blot carefully and while still moist coat alternate sections wath 

 silicone grease. A soft brush may be used, or more efficiently use 

 a 1 ml. syringe and 4^15 needle clipped off and flattened. 



3. Apply first staining procedure. 



4. Dehydrate and leave in xylene 15-30 mintites to remove coating. 

 (After 5 minutes in xylene, blotting with filter paper helps to re- 

 move grease) 



5. Rehydrate; apply coating to stained sections. 



6. Apply second staining procedure. 



