142 METHODS OF MICROSCOPICAL RESEARCH. 



to remain for twenty-four hours in the final water, 

 to which add 8 or 10 drops of nitric acid to each 

 half pint. Transfer the sections to alcohol for an 

 hour before staining them. To bring out details of 

 structure and to display cell walls, &c., there is no 

 better stain than logwood, and for singly stained 

 vegetable sections it is to be recommended in pre- 

 ference to all other staining fluids. The following 

 process will give admirable results : 



1. Remove the section from alcohol to water for 

 a few minutes. 



2. To 3 per cent, alum solution for ten minutes. 



3. Stain in aqueous logwood stain. 



4. Place in alum water to remove stain from 

 surfaces. 



5. "Wash thoroughly in water. 



6. Dehydrate in strong alcohol. 



7. Clear in xylol and phenol. 



8. Mount in xylol balsam. 



The Double Staining and Mounting of 

 Botanical Sections. 



1. Bleach the sections for six hours in the liquid 

 already described. 



2. Soak them in water, to be several times 

 changed, for twenty-four hours. 



3. Place them, for twelve hours, in the following : 



MORDANT SOLUTION. 



(a) Sulphate of Aluminia, 10 grains. 



Dissolved in Distilled Water 200 grains. 

 (6) Acetate of Lead, 30 grains. 



Dissolved in Distilled Water, 600 grains. 



Add a to b until precipitation ceases, then allow 

 the whole to settle and syphon off the clear liquor, 



