a. Chem. [f. L. lact-, lac milk + -IC.] Of or pertaining to milk. Lactic acid (C3H6O3), the acid formed in sour milk. Lactic fermentation, the souring of milk, induced by certain bacteria, which decompose the milk sugar.

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1790.  Kerr, trans. Lavoisier’s Elem. Chem., 121. Lactic acid.

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1822.  Imison, Sci. & Art, II. 139. The lactic acid is found in sour whey.

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1874.  Roscoe, Elem. Chem., xxxiv. 367. Lactic acid is contained in sour milk, and is formed from sugar by a peculiar change called the lactic fermentation.

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1879.  St. George’s Hosp. Rep., IX. 163. Treatment was by port-wine, salicylate of soda, and lactic acid spray.

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