Experiment No. 18
Gelatine in Cream or Milk
To 20 cc. of milk or cream in a beaker add 20 cc. of acid mercuric nitrate and about 40 cc. of H2O. Let stand for a few minutes and filter. Filtrate will be cloudy if gelatine is present.
Add ½ cc. of a dilute solution of picric acid—a heavy yellow precipitate indicates gelatine.
Acid Mercuric Nitrate.—1 part by weight of Hg, 2 parts HNO3 (sp. gr. 1.42). Dilute 25 times with water.