Baron von Justus Liebig

Justus Liebig, Baron von , 1803-73, German chemist. As professor at Giessen (1824-52), he was among the first to establish a chemical teaching laboratory; there some of the leading chemists of the 19th cent. were trained. He was professor at Munich from 1852 to 1873. Liebig improved methods of organic analysis and investigated organic compounds such as uric acid. He discovered chloral and was one of the discoverers of chloroform. He made valuable contributions to agricultural chemistry. Liebig refuted the prevalent theory that plants derive their nourishment from humus and emphasized the importance to plants of the nitrogen and carbon dioxide of the air and of the mineral constituents of the soil; subsequently he did important work in the development of artificial fertilizers. His works include Organic Chemistry in Its Applications to Agriculture and Physiology (1840, tr. 1840).

Liebig, Baron Justus von (1803–73) German chemist. He was the first to realize that animals use oxygen to get energy from food, although he incorrectly thought that muscular power is a result of protein oxidation. Liebig also showed that plants derive their minerals from the soil, and introduced synthetic fertilizers into agriculture.

Liebig, Baron Justus von (1803–73) A German chemist who contributed much to the systematization of organic chemistry, to the early development of biochemistry, and to agricultural chemistry. In 1840 he published Die organische Chemie in ihrer Anwendung auf Agrikulturchemie und Physiologie (‘Organic chemistry in its application to agricultural chemistry and physiology’), in which he showed that plants take up nutrients in simple chemical form and that nutrient deficiencies in soils may be remedied by the application of mineral fertilizers. He maintained that plant growth is limited by the availability of the scarcest essential nutrient (his law of the minimum). Others expanded on this work later to produce a broader appreciation of the ‘limits of tolerance’, recognizing that maximum as well as minimum thresholds exist for all commodities (not only chemicals) that are essential to plant and animal growth. See also SHELFORD'S LAW OF TOLERANCE.