Johann Heinrich Wichern, a German philanthropist, born in Hamburg, April 21, 1808. He studied theology at Göttingen and Berlin. In 1833 he founded at Horn, near Hamburg, a reformatory for vagrant children, called Rauhes Haus, and opened it with 12 inmates. At present the institution has several hundred inmates and 20 buildings. Among its departments or separate institutions are that for redeeming neglected children, grouped together in families of 12, occupied in agricultural and other labors, and educated in classes of 24; that of " brothers," or assistants engaged as teachers and superintendents, selected from respectable mechanics and other avocations, whom a probation of three years qualifies for " inner missions " in Germany and foreign countries, and as officers of prisons; and the publishing department, agency, and bookbinding establishment. The inner missions, originally formed among the pietists of the Evangelical church, were organized in 1843, and Wichern became the leader. In 1848 a central committee was organized at his suggestion, which sends missionaries all over the world.

The Rauhes Haus became the principal institution of the mission, and since 1844 has appeared a monthly periodical, Fliegende Blatter des Rauhen Hauses, founded and edited by Wichern. The annual expenses for each child are estimated at $50. The reform of the whole system of prisons and reformatories in Germany and other countries was due to his influence, and his Rauhes Haus became the model of the colony of Mettray and of other agricultural colonies and kindred institutions. In 1858 he was placed at the head of all the Prussian penal and correctional institutions, with the title of chief consistorial councillor in connection with the ministry of religion. He has published Die Innere Mission der deutsch-evangelischen Kirche (Hamburg, 1849; 2d ed., 1850), Festbüchlein des Rauhen Hauses (3 vols., 1856), Unsere Lieder (4th ed., 1870), etc.