Chemical Analysis of Milk and its Products. 231 



and strong H 2 SO 4 (sp. gr. 1.82-1.84) is added. A vio- 

 let ring is formed at the junction of the two liquids if 

 formaldehyde is present; if not, a slight greenish tinge 

 will be seen. The violet color is not obtained with milks 

 containing over .05 per cent, formaldehyde. 1 



i Chem. News, 1896, No. 71; Milchzeitung, 1896, 491; 1897, 40, 667; The An- 

 alyst, 1895, 152, 154, 157; 1896, 285. 



