GLYCEEOPHOSPHORIC ACID. 121 



sulphuric acid and twelve parts of water for thirty- six 

 hours. Add excess of milk of lime or baryta; boil 

 and strain. Acidify very slightly with sulphuric acid, 

 filter, and evaporate to a low bulk. The granular 

 crystals which form on standing must be removed, 

 boiled with alcohol, filtered, and the solution evapo- 

 rated to crystallisation. The crystals will consist of 

 glykokoll recognised by the usual tests. 



7. Boil gelatine with strong caustic potash till com- 

 pletely decomposed ; neutralise with sulphuric acid, 

 and evaporate to a low bulk. From the residue warm 

 alcohol will extract leucine, which may be recognised by 

 the usual tests (see leucine). 



Globulins. 1. Pound a number of crystalline lenses 

 with water, filter, evaporate the filtrate in vacuo over 

 sulphuric acid, and wash the product with ether and 

 dilute alcohol. Examine as follows : 



2. Treat with water ; it will dissolve. Filter and 

 heat the solution. At 73C it will become opalescent ; 

 at 93 it will coagulate. 



3. Pass through the aqueous solution a current of 

 carbonic anhydride; a precipitate will fall soluble in 

 pure water. 



4. The other reactions are similar to albumine (q. v.). 



Glycerophosphoric acid, C 3 H 9 P0 6 . 1. Obtain by 

 synthesis as follows : Digest glycerine with an excess 

 of glacial phosphoric acid, mix with water, neutralise 

 with baryum carbonate, then with baryta water, filter, 



