DECALCIFYING FLUIDS. 



In the case of bony structures or tissues so impregnated 

 with Lime Salts as to interfere with section cutting, the 

 material must be decalcified in one of the following solutions. 

 The general plan is to combine an Acid capable of dissolving 

 out the mineral matter with a hardening agent which will 

 prevent swelling of the tissues. 



Hydrochloric Acid is generally used with Alcohol. Diluted 

 Nitric Acid may be used alone, but usually in conjunction 

 with Alcohol, Chromic Acid, or an equivalent quantity of 

 Potassium Bichromate. 



The older the bone the stronger will be the acid required. 



It is advisable to harden first in Alcohol or Bichromate 

 before decalcifying, except in the case of Ebner's solution 

 where the two processes go on together. 



(i.) ARSENIC ACID. 



4 p. c. aqueous solution, used at a temperature of 30 to. 

 40 0. 



It acts rapidly. Tissues after softening should be kept in 

 Alcohol. 



(ii.) CHROMIC ACID. 



0-1 to 0-5 p. c. aqueous solution. 



Used for softening small pieces of bone, but when use 

 alone it causes much shrinkage in the tissues. 

 It is best used in conjunction with Nitric Acid. 



