Weigert
Name: Carl Weigert
Achievements: Nerve cell work.
Born: March 19, 1845; B. Munsterberg, Strehlen, Silesia, Prussia (now Strzelin, Poland)
Died: August 4, 1904; Frankfurt-am-Main, Germany. Aged 59
Field & Discipline: Science; Pathology; Neurology; Pathologist
Language: German
Education: Breslau Gymnasium (1857-62); University of Breslau (1862-64); University of Berlin (1664-66)
Major Work:
"On a New Method of Examining the Central Nervous System" (1884)
Life & Times:
Carl Weigert was the cousin of the medical scientist [cousin was] Ehrlich*. At the University of Berlin for a time he worked as personal assistant to the pathologist [assistant to] Virchow*. In 1866 he received his medical degree from the University of Berlin.
In 1871 Weigert was appointed clinical assistant to Hermann Lebert at Breslau, and three years later to Julius Cohnheim, under whom he qualified as a teacher of pathology in 1875.
A year earlier he had produced his first major work, on the eruption of smallpox on the skin (1874), in which he laid the foundation of a new area of research in pathological anatomy: the demonstration of the primary damage of cells and tissues by external influences.
In 1871, using the improved microtome (a specialised cutting instrument), Weigert dissected the diseased tissue into sections and developed a technique that allowed him to differentiate tissues under the microscope. By staining the tissue sections, he was then able to demonstrate the presence of bacteria (using techniques developed more than a decade earlier for staining animal tissues with dyes) and found that dead ("fixed") bacteria would become heavily stained with the dye picrocarmine. This advance would prove of the greatest importance for the subsequent work of [influenced] Koch*, who discovered the tuberculosis bacillus (1882), Paul Ehrlich [who developed a new technique for staining live tissue with aniline dyes in order to identify it (1883)] and [influenced] Gram* (1884).
Weigert detailed his work in a two-volume book (1874-75), in which he began to develop the theory of the "coagulation necrosis", and to illustrate the reparative (bioplastic) processes of the supporting tissue. In advance of the work of the French bacteriologist Emile Roux, he also developed the concept that the cells of an organism are in equilibrium among themselves, and that cells cannot disappear without the neighbouring cells attempting to take over their place.
In the 1880s, he would apply this theory of the secondary, reparative processes to the substitute growth of neuroglia following atrophy of the nervous parenchyma. In 1885 Weigert was offered the appointment of director of the Pathological-Anatomical Institute of the Senckenberg Foundation in Frankfurt, where he proved himself an inspiring teacher, attracting students from all over Europe to the Institute.
During the 1880s, at both Leipzig and Frankfurt, Weigert conducted his most important work, in the field of neuro-histology. In 1884 he presented his perfected method for staining myelin sheaths, (the white, insulating sheaths on the axon of many nerve fibres, which are deposited by Schwann cells in layers surrounding the nerve fibres of the central and peripheral nervous systems of many animals, and are composed of fatty materials, protein, and water). This enabled scientists to establish a reliable anatomy of the central nervous system.
During the 1880s Weigert also experimented with the staining of elastic fibres and fibrin (an insoluble protein produced in response to bleeding and is the major component of a blood clot). These latter experiments (1887) were also important for general pathology, as they influenced the study of inflammation and the theory of thrombosis. During these years Weigert also did studies on the genesis of acute general miliarial tuberculosis (which affects the veins and thoracic duct), pointing out its spread from a tubercular source before the agent of the disease was even known. Weigert remained as director of the Frankfurt Institute until his death from a coronary embolism.
Extra Connections: He taught [taught] Almroth Wright*
Assessment: 1884 he described the definitive method of staining myelin sheaths, allowing the description of the anatomy of the central nervous system.
Oneliner: Carl Weigert, pioneer in nerve cell work
Bibliography:
- Dictionary of Scientific Biography.
- Encyclopedia Britannica.
Father: Unknown
Mother: Unknown
Siblings: Unknown
Spouse: None
Children: None