Lactic acid is found in sour milk. It is also produced by the action of a special ferment on sugar, and is one of the normal constituents of the gastric juice. It is a pale-yellow, syrupy, inodorous liquid, with acid taste.
Lactic acid aids digestion and promotes appetite. It is credited with the power of dissolving fibrinous exudations, but its use as an application is very painful. Flatulence and epigastric pain result from its too free administration.
It enters the blood as alkaline lactates, is decomposed, and excreted by the urine as carbonic acid.
The pure anhydrous 1 acid is a colorless, transparent, volatile, and inflammable liquid, so poisonous that its fumes alone will cause death.
Its discoverer, Scheele, is supposed to have died from inhaling it. It is not official, and is kept only in laboratories. It is found in nature in a number of vegetable substances, viz., peach kernels, bitter almonds, wild cherry, cherry laurel, etc.