THE MICROSCOPE. 29 



sulphuric acid has the power of converting the 

 celhilose into starch. 



The strong solution of potash (liquor potassse) can 

 also be employed with advantage in softening and 

 making clear opaque animal and vegetable sub- 

 stances. Nitric acid has even a greater solvent 

 power than sulphuric acid, and may be used for the 

 same purposes. While using these powerful acids 

 great care should be taken to prevent the trans- 

 parency of the object-glass becoming impaired by 

 contact with the acids, or by long exposure to 

 their vapours. 



