LESSON IV 



Peptones and Albumoses Peptones Albumoses. 



Peptones 



Tests for peptones. 



Prepare a solution of peptone. 1 



(1) Boil : no coagulation. 



(2) Make strongly alkaline with caustic soda, and add a 

 drop of a dilute solution of copper sulphate : a pink colour 

 is produced (biuret reaction). 



(3) Add ammonium sulphate to saturation : no precipitate. 



(4) Add nitric acid, drop by drop : no precipitate. 



(5) Add nitric acid in the presence of chloride of sodium : 

 no precipitate. 



(6) Add an excess of picric acid : no precipitate. 



(7) Add absolute alcohol : a white precipitate, readily 

 soluble in water. 



(8) Add tannic acid : a precipitate, soluble in excess. 



(9) Add Millon's reagent, and boil : a red colour. 



1 Peptone puriss. (Adamkiewicz), obtained from E. Merck of Darm- 

 stadt. 



