[The scientific work of W. J. Schmidt (author's transl)].

Ten examples from W. J. Schmidt's workshop illustrate the method of ultrastructural research before the advent of the electron microscope. The consistency is shown with which the research worker W. J. Schmidt pursued his goal, how he succeeded in making fundamental discoveries with his polarizing microscope, and interpreted the results of his indirect structural investigations in such a forward-looking and clearsighted manner that many of them were confirmed by direct reproduction in the electron microscope. This makes W. J. Schmidt one of the great pioneers of ultramicroscopic structural research. He was an extremely prolific writer. His list of publications numbers 404 scientific contributions, three classical books among them. The last of these three monographs was written in 1971; its title is "Polarizing Microscopy in Dental Tissues"; it deals with the ultrastructure of teeth, a subject which never ceased to attract his attention during the more than 50 years of his career as a scientist. It was his intention to write such a textbook on the ultrastructure of teeth during his retirement, a task which he accomplished in spite of the infirmities of old age, thanks to his unbroken will to work. Another characteristic feature of W. J. Schmidt was his extraordinary insistence on complete independence; there are only four among his 404 publications which he wrote, at an advanced age, jointly with Helmut Ruska, and the dental monograph he published in callaboration with A. Keil. Everything else was entirely his own effort. His capacity for work was almost inexhaustible. In 1937, for instance, he published 18 scientific papers, among them his richly illustrated protoplasm monograph of 388 pages. His inflexible will to observe everything personally and to interpret and edit his findings alone was part of his special intellectual constitution. In discussions he stubbornly defended his point view and considered suggestions and new ideas only after he had tested them with his own experiments. This had already become evident at the beginning of his career in a discussion with Ambronn of the nature of birefringence of organized substances. But once he had accepted something as proved he propounded it with persistence and enthusiasm.