132 Hematoxylin Staining (chap. 12) 



19. xylene 2-3 minutes or longer. 



20. xylene 2-3 minutes or longer. 



21. mounting medium; keep sections moist with xylene during this 

 process. They must not dry. Add cover glass, page 1 15. 



results: 



nuclei — deep blue 



cytoplasmic structures — pink, rose, etc., depending on counterstain 



comments: 



1. Slides may be left in higher alcohols and xylene longer than sched- 

 uled (indicated by "or longer"), but do not leave them indefinitely 

 in any solutions weaker than 80 or 95% alcohol. Lower alcohols and 

 water can loosen the sections from the albumen. 



2. Isopropyl alcohol can be substituted for ethyl alcohol in this sched- 

 ule, but cannot be used as a stain solvent. 



3. Two to five minutes for Delafield's (step 9) is an approximate time 

 only. This may have to be varied according to the tissue used. Tis- 

 sues can be individualistic, often due to the type of fixative employed 

 on them, and a certain amount of trial and error may be required 

 to develop the exact timing schedule. 



4. The cause of some difficulties can be problematical. Poor staining 

 can result from improper fixation, leaving gross tissues too long in 

 alcohol or iodine, faulty processing during preparation for embed- 

 ding, or careless handling of the slides in preparation for staining. 

 In many instances no amoimt of trial and error will produce a per- 

 fect stain. The only correctable faults are those made during de- 

 paraffinization and hydration of the slides and the slides should be 

 reversed through the solutions, back to xylene. Change to fresh solu- 

 tions and try again. 



5. Sometimes too many slides have been taken through the fluids and 

 they are contaminated. If as many as 20-40 slides are being stained, 

 use two changes of xylene in step 1 and follow step 20 with a third 

 change. Prevent further contamination by draining slides properly. 

 On removing them from a solution, touch the edges against the inner 

 surface of the staining jar, and then against paper toweling. But do 

 not be too thorough and let the slides dry. Merely drain off excess 

 liquid. 



6. Hematoxylin staining must be left in a "blued" condition. The orig- 

 inal pinkish color of the hematoxylin, like Delafield's, must be con- 

 verted to a blue color by alkalinity. In the progressive method this 

 is accomplished in running water to remove excess dye and start the 



