- Weigert's iodine solution
- Weigert's iron haematoxylin stain
- Weigert's law
- Weigert's stain and method
- Weigert-Gram stain
- Weigert-Meyer rule
Biography of Carl Weigert
Carl Weigert was born in the same district in Silesia as his cousin Paul Ehrlich (1854-1915), his junior by nine years. After attending the Gymnasium in Breslau, Weigert studied medicine at the University of Breslau, where his teachers included Ferdinand Cohn (1828-1898), Rudolf Heidenhain (1834-1897) and Wilhelm von Waldeyer-Hartz (1836-1921). Weigert continued his studies in Berlin, where he worked as Rudolf Virchow’s (1821-1902) amanuensis, and also studied for a period in Vienna. In 1866 he received his medical degree from the University of Berlin for a dissertation, De nervorum laesionibus telorum ictu effectis. Two years later Weigert became an assistant of Waldeyer-Hartz, professor of pathology at Breslau.
Weigert saw active service during the Franco-Prussian War in 1870-1871, and in 1871 became clinical assistant to Hermann Lebert (1813-1878). In 1874 he became assistant to Julius Cohnheim (1839-1884), who had been attracted by Weigert's authoritative paper on the pathology of smallpox. Working under Cohnheim, Weigert was habilitated as a teacher of pathology in 1875.
In April 1878 Weigert accompanied Cohnheim from Breslau to the University of Leipzig, where Cohnheim the following year succeeded Ernst Leberecht Wagner (1829-1888) as ordinarius of pathology. By decree af the Königliches Ministeriums des Cultus und öffentlichen Unterrichts of March 25, 1879, Weigert was appointed professor extraordinary of pathological anatomy at Leipzig, and on August 4, 1880, under festive circumstances, gave his inaugural address.
However, Cohnheim had fallen ill, and was only rarely able to conduct autopsies. Carl Weigert was of great support to Cohnheim in this period, delivering Cohnheim's lectures and doing his autopsies, but when Cohnheim died in 1884, the faculty did not nominate him even as a possible successor.
Weigert resigned from his post the following year and had decided to take up medical practice, but he was dissuaded by an offer to become chief of the pathology section of the Senckenbergisches Pathologish-Anatomisches Institut in Frankfurt am Main. The "Institut" was an ill-equipped, old, private cottage, where, in the early 1900's, Paul Ehrlich and Ludwig Edinger (1855-1919) were chiefs of the two other sections. Here the three of them – Weigert, the quiet introspective unremitting worker, Ehrlich, the fighter and the most embullient, Edinger, the solid purveyor of constantly new ideas, with the genius to find rapidly the answers he was seeking – brought to Frankfurt a position equalling that of other German universities. Weigert attracted students from many countries. He held this post until his death at age fifty nine.
Weigert’s most notable personal characteristic was his excessive modesty. He was plagued by doubts about the value of his work and was never satisfied with what he had accomplished. Yet, he was indisputably successful in teaching advanced science students, both in the classroom and in the laboratory.
With his first major work on the eruption of smallpox on the skin (1874), Weigert opened a new area of research in pathological anatomy – the demonstration of the primary damage of cells and tissues by external influences.
In 1871 he was the first to stain bacteria and was able to demonstrate the presence of bacteria in tissue sections. This advance was of the greatest importance for the subsequent work of Robert Koch. According to Ehrlich, Weigert’s monograph of 1874-1875 already contained “the points of view that guided his work for the rest of his life.” The problem of the selective action of dyes on biological materials (microchemical reactions), which led Ehrlich to develop chemotherapy, led Weigert to make revolutionary advances in histological techniques. These advances made it possible for researchers to gain fundamental insights into the fine structure of the nervous system. Weigert is thus closely associated with brain and spinal cord research and with neurology and psychiatry.
Weigert's research on inflammation, coagulation necrosis, pathogenesis of tuberculosis, Bright's disease, morphology of neuroglia, and biology of the cell were significant contributions and show that his interests encompassed the entire realm of pathology.
Weigert achieved his most successful results in the field of histological staining techniques, which he improved considerably. In 1884, after long preliminary investigation, he presented in 1884 the definitive method for staining medullary sheaths (myelin sheaths). This method enabled scientists to establish a reliable anatomy of the central nervous system.
According to the pathologist Otto Lubarsch (1860-1933), Weigert was
“ . . . inwardly happy, a truly distinguished and good man, who viewed the weakness of those around him with the deep sense of humour of the philosopher and who reacted only mildly against those who wished to harm him. Nothing human was foreign to him, and after a day of hard work he sought relaxation in literature and society, amusing everyone with his warm-hearted humour and his witty conversation. His contact with Scandinavian students prompted him to learn their languages.”
Weigert in 1899 became honorary member of the Institut für experimentelle Therapie and appointed Geheimer Medizinalrat. However, he died a disappointed man, for his hope to become Ordinarius was never fulfilled. This was not only because he was of Jewish extraction, but also because he lacked the self-assurance needed to fill the role