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702 PHARMACEUTICAL BOTANY 
or short segments of other hard material are placed in this acid 
(which should be kept in a bottle coated internally with a thick 
layer of paraffine) for from 3 days to a week, depending on the 
size of the objects, with one or two changes of the acid. The acid 
is then. washed out thoroughly with running water for 2 to 5 
hours. This treatment completely frees the tissues of all mineral 
deposits without affecting the organic structure. 
ScHULZE’s MACERATION PROCESS 
This method is employed for the separation of cells. Radial- 
longitudinal sections, that may be cut with a pen knife, are placed 
in a beaker or test tube containing 50 cc. of nitric acid of specific 
gravity 1.3 (about 2 volumes of nitric acid and 1 volume of water 
will serve the purpose). To this add 1 gm. of chlorate of potash 
crystals and heat gently until the reddish color which first 
appears in the tissues has disappeared. Stop the action by pour- 
ing the whole of the contents into a vessel containing water and 
wash well with water. The cells can now be readily separated 
with dissection needles and mounted in water for examination. 
Do not mount in glycerine, for it makes the already bleached 
elements too transparent. 
