154 MUOINE. 



12. Add to 100 cc. of milk solution of calcium 

 chloride ; the caseine is precipitated ; filter ; add 

 potash solution to precipitate excess of calcium, and 

 estimate the sugar present in the filtrate with standard 

 solution of potassio-tartrate of copper. 

 Milk contains 2 to 4% caseine. 



1-5 to 4% fat. 

 4 to 5% sugar (lactose). 



Mucine. 1. Dilute mucus with four vols. of water 

 and filter. Digest the insoluble matter (mucine) with 

 a weak solution of potash, filter, neutralise with acetic 

 acid, wash the precipitate with water, alcohol, and 

 ether, and use it for the following reactions. 



2. Dry a portion and burn on platinum foil. A 

 white alkaline ash containing calcium phosphate will 

 remain. 



3. Fuse with caustic potash, dissolve in water, and 

 add a drop of lead acetate. No black precipitate, 

 showing the absence of sulphur. 



4. Mix with cold water and boil. It will gradually 

 dissolve. Add alcohol; the mucine will be precipitated 

 in flakes. 



5. Dissolve mucine in a dilute acid or alkali, and 

 add potassium f err o cyanide. No precipitate. 



6. Dissolve in glacial acetic acid and boil. Add 

 potassium ferrocyanide ; white precipitate. 



7. Heat with concentrated nitric acid : the mucine 

 will turn yellow and dissolve. 



8. Dissolve in very weak caustic potash, and add 

 basic lead acetate or tannic acid ; white precipitate. 



