JUSTUS VON LIEBIG, one of the greatest chemists of the nineteenth century, was born May 12th, 1803, at Darmstadt, Germany, where his father was a “dry salter” and dealer in dye stuffs. The chemical experiments made by his father in attempting to purify his dyes are thought to have given the first impulse to the scientific genius of the son. It is said that even as a boy Justus Liebig acquired through persistent experimenting a greater knowledge of chemistry than that of “many full-grown professors of the science.” Under the impulse thus gained, he studied at Bonn and Erlangen, graduating from the latter university in 1822 and studying afterwards under Gay-Lussac at Paris. On his return to Germany he became professor of Chemistry in the University of Giessen, where he remained for twenty-five years. During this time he published his “Letters on Chemistry” and other works of the highest merit, which made him a world-wide reputation. In 1852 he left Giessen for the University of Munich, where he served as professor of Chemistry until his death, April 18th, 1873. In 1845 he had been “ennobled” as “Freiherr von Liebig,” and it is to this that he owes the title of “Baron,” by which he is frequently called. His work practically founded the science of organic chemistry, out of which some of the greatest discoveries of the age have developed. His “Letters on Chemistry” are admirable in their methods of expression. He has a faculty many scientific investigators lack,—that of making himself so clearly intelligible that he transmits to his readers no small part of his own enthusiasm for his subject.