LACTIC ACID

(Lat. lac.) The acid of sour milk. A similar acid is obtained from the fermented juice of the beet root. It appears to consist of 6 atoms of carbon, 5 of hydnogen, and 5 of oxygen, its equivalent being 81. LACTO'afETER. (Lat. lac, and metrum, a measure.) A term applied to a gla tube for ascertaining the proportion which the cream bears to the milk of any particular cow, or of the produce of a whole dairy. The tube is about half an inch in diameter, and a foot in height, with a graduated scale marked on the outside. It is filled with milk when newly drawn from the cow, and as it cools the cream rises to the surface, and the proportion which it bears to the milk is ascertained by counting the degrees opposite to e.ich. [s. 645]