322 HISTOLOGICAL TECHNIQUE. 



When rapid decalcification is necessary nitric acid and phloro- 

 gluein, which restrains the destructive action of the acid, may be 

 used. The solution is prepared by dissolving 1 gram of phloro- 

 glucin in 10 cc. of pure nitric acid. To this 100 cc. of 10 per cent. 

 nitric acid are added. Decalcification takes place within a few hours 

 in this solution, which contains about 20 per cent, of nitric acid. 

 The tissues should then be washed and hardened. 



Another rapid method which combines decalcification with hard- 

 ening is to place the fresh tissues in a large bulk of 5 per cent, 

 nitric acid in 80 per cent, alcohol. After decalcification has taken 

 place the tissues are hardened in alcohols of increasing strength, 

 large quantities being used in order to remove the acid. Before 

 staining, the sections should be washed thoroughly in water to get 

 rid of any residual traces of acid. 



