86 Methods in Plant Histology 



the sections are still somewhat overstained in safranin. Wash for 

 1 or 2 minutes in 95 per cent alcohol to remove the acid. A trace of 

 sodium carbonate, just enough to make the alcohol alkaline, may be 

 added to the 95 per cent alcohol. If any acid remains, the safranin 

 will fade. Dehydrate in absolute alcohol 1 to 5 minutes, clear in 

 xylol, or first in clove oil and then in xylol, and mount in balsam. 



For convenient reference, the process may be summarized, but 

 it must be remembered that all the schedules are intended merely to 

 introduce the method to the beginner. 



1. Sections in 95 per cent alcohol. 



2. Stain in safranin, 24 hours. 



3. 50 per cent alcohol until the stain becomes weak in cellulose walls, 

 but not until it is removed entirely. 



4. Anilin blue, 2 to 10 minutes. 



5. 95 per cent alcohol, 2 to 5 seconds. 



6. 95 per cent alcohol, slightly acidulated with hydrochloric acid, 

 5 seconds. 



7. 95 per cent alcohol, with or without a trace of sodium carbonate, 

 1 or 2 minutes. 



8. Absolute alcohol, 1 to 5 minutes. 



9. Xylol, 1 to 5 minutes. The xylol may be preceded by clove oil. 

 10. Mount in balsam. 



Lignified and suberized walls should stain bright red and cellulose 

 walls bright blue. To make this beautiful combination a success, it- 

 is necessary to be very careful. If too much safranin is extracted 

 at stage 3, the acid at stage 6 will still further weaken the red stain 

 and the contrast will not be sharp. 



Safranin and Light Green (Land's Schedule) .--This is another 

 beautiful combination and the student should be successful from 

 the first, since the light green is simpler to apply than either Dela- 

 field's haematoxylin or anilin blue. 



Land uses either aqueous, anilin, or alcoholic safranin, and 

 uses the light green in clove oil, or in a mixture of clove oil and 

 absolute alcohol. Make a saturated solution of light green in clove 

 oil. Since the solution takes place slowly, the mixture should stand 

 several days before using. If a small quantity of absolute alcohol 

 be added to the clove oil, the stain dissolves more readily. For 



