The Encyclopedia Americana (1920)/Liebig, Justus, Baron von
LIEBIG, Justus, yoos'toos le'bĭg, Baron von, German chemist: b. Darmstadt, 12 May 1803; d. Munich, 18 April 1873. He studied in Bonn and Erlangen, was graduated in 1822 and the same year went to Paris, where he gained the favor of Humboldt by his paper on fulminic acid and the fulminates, read before the French Academy (1824). He thus obtained access to the private laboratory of Gay-Lussac. In 1824 he was appointed extraordinary professor and in 1826 ordinary professor of chemistry at Giessen. Here he opened the first experimental laboratory for college students and the university soon became the European centre of chemical studies. He had remarkable success as a teacher and pupils streamed into his classroom from every country. The most illustrious chemists of the last century acknowledged their obligations to him as their master. He gave chemistry a settled position in Germany and turned it into a real science to be taught and learned by means of experiment. As an original investigator in the domain of chemistry he has shown himself a reformer of the sciences of physiology and agriculture. He may be said to have been the founder of modern organic chemistry and its necessary method of analysis. He analyzed many organic acids; discovered chloroform and chloral; he made the theory of the composition of ether and the oxidization of alcohol subjects of new experiments, in the course of which he discovered aldehyde. He determined the basicity of many acids; analyzed the chemical composition of urine and the products of uric acid and made profound inquiries into the juice of flesh and its component substances. He raised chemistry from a position of obscurity and unprofitable hypothesis into its present all-dominating position by his theory of the constitution of alcohol, ether, etc., and his work on the benzoyl compounds is especially remarkable in this connection. The industrial importance of his discoveries is great. Cyanide of potassium is now largely employed in electroplating and in the manufacture of ferrocyanides. His improved method of producing this cyanide has cheapened its manufacture, just as the discovery of aldehyde has led to improved methods in the making of vinegar and looking-glasses. The result of his great discoveries has been especially felt in medicine, agriculture and food-hygiene. His great generalization that the mineral and organic worlds were composed of the same chemical elements and were subject to the same chemical mutations revolutionizing science. He traced for the first time the transformation of inorganic into organic substances in plants, from which they were transferred to the organisms of animals. His exact statement of the elements received by plants from the soil and air enabled him to prescribe the composition of efficient fertilizers and thus, in the treatment and analysis of soils, to raise the fundamental operations of agriculture to the level of exact science. Consult Liebig, ‘The Natural Law of Husbandry’ (1863); ‘Animal Chemistry in its Application to Physiology and Pathology’ (1846); ‘Handbook of Organic Analysis’ (1853); Hoffmann, ‘The Life-Work of Liebig in Experimental and Philosophical Chemistry’ (1876). See Chemistry; Agriculture.