FISCHER, EMIL (1852-1919), German chemist, was born at Euskirchen, Rhenish Prussia, on Oct. 9, 1852. He studied at Bonn and at Strasbourg, where he graduated Ph.D. in 1874. He then acted as assistant to Adolf von Baeyer at Munich for eight years, after which he was appointed to the chair of chemistry suc cessively at Erlangen (1882) and Wurzburg (1885). In 1892 he succeeded A. W. von Hofmann as professor of chemistry at Berlin. Emil Fischer devoted himself entirely to organic chemistry, and his investigations are characterized by an originality of idea and readiness of resource which make him the master of this branch of experimental chemistry. The extraordinary merit of his re searches was recognized by all the important scientific societies in the world; in 1890 he was awarded the Davy medal of the Royal Society and elected a foreign member in 1899. He was awarded the Nobel prize for chemistry in 1902. Under his control the laboratory at Berlin became one of the most important in exis tence, and attracted to itself a constant stream of brilliant pupils. Emil Fischer died at Wannsee, Berlin, on July 15, 1919.
In 1875, he published his discovery of the organic derivatives of hydrazine (q.v.). He investigated their relation to the diazo com pounds (q.v.). His observations, published in 1886, that the hy drazones, by treatment with hydrochloric acid or zinc chloride, yielded derivatives of indol, the pyrrol of the benzene series and the parent substance of indigo, were a valuable confirmation of von Baeyer's views on indigo and its derivatives. Of greater moment was his discovery that phenyl hydrazine reacted with the sugars to form substances which he named osazones, and which served to identify such carbohydrates more definitely than had been previously possible. He next-turned to the rosaniline dye stuffs, and in collaboration with his cousin Otto Fischer, he pub lished papers in 1878 and 1879 which established that these dye stuffs were triphenyl methane derivatives. The results of this work were collected after his death and published as Untersuchungen fiber Triphenylmethanfarbstoffe, Hydrazine and Indole (1924)• Fischer's next research was concerned with compounds related to uric acid. Here the ground had been broken, more especially by von Baeyer, but almost all our knowledge of the purine group (see PURINES) is due to Fischer. In 1881-82 he established the formulae of uric acid, xanthine, caffeine, theobromine and some other compounds of this group.
His greatest work was instituted in 1894, when he commenced his great series of papers, wherein the compounds above mentioned were all referred to a nitrogenous base, purine. The base itself was obtained after much difficulty, and an immense series of de rivatives were prepared, some of which were patented in view of possible therapeutical applications. These researches were pub lished in a collected form in 1907 with the title Untersuchungen in der Puringruppe. When the work on the purine group was pro gressing satisfactorily he attacked the sugar group. Here again Fischer may be regarded as the prime investigator in this field. His researches may be taken as commencing in 1883 ; and the re sults are unparalleled in importance 'in the history of organic chemistry. The chemical complexity of these carbohydrates (q.v.), and the difficulty with which they could be got into a man ageable form—they generally appeared as syrups—occasioned much experimental difficulty; but these troubles were little in com parison with the complications due to stereochemical relations. However, Fischer synthesized fructose, glucose and a great num ber of other sugars, and showed how to distinguish the formulae of the 16 stereoisomeric glucoses (see STEREOCHEMISTRY and ISOMERISM). The study of the sugars made it necessary to examine the nature, properties and reactions of substances which bring about fermentation (q.v.). Fischer attacked the problem presented by ferments and enzymes, and although we as yet know little of this complex subject, to Fischer and his co-worker Abderhalden is due the credit of having laid the foundation of enzyme chemistry (see ENZYME) . The magnitude of his researches in this field may be gauged by his collected papers, Untersuch ungen fiber Kohlenpydrate and Fermente (1909).
From the sugars and ferments it is but a short step to the chemistry of the proteins (q.v.). By the introduction of new methods, Fischer succeeded in breaking down the complex pro teins into amino-acids and other nitrogenous compounds, the con stitutions of most of which have been solved ; and by bringing about the recombination of these units, appropriately chosen, he prepared synthetic peptides which approximate to the natural products. His researches made from 1899 to 1906 have been published with the title Untersuchungen caber Aminosauren, Poly peptides and Proteine (Berlin, 1907).
Fischer also made a number of investigations on the Walden inversion and on gallic acid derivatives of the sugars which were related to the tannins. During the World War he was very active in organizing German chemical resources. He increased the supply of ammonia available from coke-ovens, encouraged the synthetic nitric acid industry, suggested camphor substitutes and new sources of glycerine. He was particularly concerned with the prob lem of conserving the food supply.
See Fischer, Memorial Lecture, Journal of the Chemical Society (1920).