68 Botanical Microtechnique 



Staining Chart III begins with a slide that has been stained in 

 hemalum as shown in Chart I; the slide is then immersed in satranin. 

 The interval in safranin ranges from a few minutes to 12 hr. Some 

 collections of young corn stem require at least 1 hr. in safranin. Wood 

 sections cut in celloidin may take up enough safranin in 5 min. to 

 make destaining difficult. Untested material should be tried at 

 intervals of 10, 30, and 60 min. and 8 to 12 hr. After removal from 

 safranin and rinsing in water, all cells of the section are found to be 

 stained deep red, the blue color of the hemalum being masked. 

 Dehydration and differential destaining are accomplished simultane- 

 ously by passage through the alcohol series. Safranin is removed from 



STAINING CHART III 



Hemalum and "Specific" Counterstain 

 Pre-Staining Operations as in Chart I 



Hemalum to resin and 



correct intensity cover glass 



i t 



safranin ^ 1^^^^ III 



1-12 hr. ^ 



i 

 ■wash 



t 

 xylene II 



30% xylene I 

 alcohol ^ 



i carbol- 



50 7c xylene 

 alcohol 



i 

 7iV/c 



alcohol 



t 



aljsolute 

 alcohol 



95% al)s(>hite 



auono 



hoi ^ alcxjliol 



cytoplasm aud uulignihed tissues by 50 and 70% alcohol and at a 

 slower rate by similar grades ol acetone. Higher coudutrations of 

 alcohol and anhydrous alcohol also dissohe the safranin. hut 90% 

 acetone and aidiydrous adtone have slight destaining action. Acetone, 

 therefore, ])erniits easier control ol desiaining than does alcohol. 

 Lignified tissues, (utin. and |)laslids retain safranin tlnoughout 

 suitably rapid dehydration. Ihe correct stain has been attained when 

 lignihed (cll walls are a dear, transparent red and uidignified Avails 

 are blue, with little or no reddish tinge. C^hloroplasts may be blue, 

 violet, or red. In order to make chloi()i)lasts red enough to show up 



