tion have hitherto been so narrow that the public has not yet been able to recognize his greatness as a thinker on high questions of scientific philosophy. We do not say that Prof. Du Bois-Reymond is more than a scientist, for, in our view, that is a term of great breadth, but we do say that he is much more than a scientific specialist. He is a comprehensive and cultivated thinker. For largeness, originality, and independence of view, for depth of analysis and thoroughness of erudition, and for clearness, vividness, and vigor of style, he has no superior among his distinguished German contemporaries. His celebrated address on "The Limits of our Knowledge of Nature," which attracted great attention in Europe, was first presented to the English-speaking public in The Popular Science Monthly for May, 1874; and we now offer another of his productions to our readers, which is the subject of comment elsewhere. Prof. Du Bois-Reymond is in the vigorous maturity of his life, and, although he has done a great deal of valuable work, much more is still expected from him. We hope in due time to bring before the American public some other of his able productions that are suited to popular appreciation.
Emil du Bois-Reymond was born in Berlin, November 7, 1818. His father, a native of Neufchâtel, in Switzerland, had in his youth been a watch-maker, but subsequently entered upon a literary and official career in Berlin. Du Bois-Reymond's mother was descended from the Huguenots, who were driven from their country by Louis XIV. Among his maternal ancestors we must not omit to mention the celebrated artist and engraver, Daniel Chodowiecki, called by some the Hogarth of Germany.
After the fashion prevalent in Germany, Du Bois-Reymond first attended a primary school, then the Collége François of his native town; but, when he was about eleven years old, his parents went to live several years in Switzerland, and during this period he was a pupil of the College of Neufchâtel. The French language, therefore, was from his childhood as familiar to him as German.
Later on, we again find Du Bois-Reymond in Berlin; and at the age of eighteen he became a student at the university of that town. It is said that, like many others who afterward distinguished themselves in natural science, he first devoted himself to theological studies, and that, during a session, he regularly attended Neander's lectures on ecclesiastical history. Chancing, however, to enter the lecture-room of the celebrated chemist Mitscherlich, he felt irresistibly drawn toward his true vocation. He now studied chemistry, natural philosophy, mathematics, and during the summer of 1838, which he spent at Bonn, on the Rhine, also geology, without any very definite aim.
This was eventually pointed out to him by a friend, the late Dr. Edward Hallmann, who, with greater scientific experience, convinced him that, of all the branches of science, the study of animated Nature affords the highest interest and includes the deepest problems, and
