PTYALINE. 163 



more soluble in hot, alcohol and ether. In water it 

 swells up to an opalescent solution, which is coagu- 

 lated by the addition of salts. From the coagulated 

 flakes the salts are almost entirely removed by washing 

 with water, leaving the protagon unchanged. 



3. In warm glacial acetic acid it dissolves to a clear 

 solution, which deposits crystalline protagon on 

 cooling. 



4. It softens at a temperature of 75 to 80, and 

 decomposes below 100. When burned it leaves a 

 dense charcoal difficult of combustion and containing 

 phosphoric acid. 



5. By the action of alkalies or boiling dilute HC1 it 

 yields cerebrine and the decomposition products of 

 lecithins (q.v.). (See Cerebric Acid.) 



Pty aline. 1. Treat a quantity of saliva first with 

 dilute phosphoric acid and then with lime water. 

 Decant the clear liquid ; shake up the precipitate with 

 distilled water and filter. The filtrate is a solution of 

 the active ferment ptyaline, which can be precipitated 

 by the addition of alcohol. 



2. Treat some starch with the above-mentioned 

 aqueous solution at a temperature of 35; it will 

 dissolve and be finally converted into dextrine and sugar. 



3. The active properties of ptyaline are destroyed by 

 a temperature above 60 0., or by strong acids or 

 alkalies. 



4. Treat a little solid ptyaline with nitric acid. No 

 yellow colour will be produced, showing that it is not 

 an albuminoid. 



