Heinrich Wilhelm Gottfried von Waldeyer-Hartz (6 October 1836 – 23 January 1921) was a German

anatomist Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having it ...

, known for summarizing

neuron theory The neuron doctrine is the concept that the nervous system is made up of discrete individual cells, a discovery due to decisive neuro-anatomical work of Santiago Ramón y Cajal and later presented by, among others, H. Waldeyer-Hartz. The term ' ...

and for naming the

chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins ar ...

. He is also remembered by anatomical structures of the human body which were named after him:

Waldeyer's tonsillar ring Waldeyer's tonsillar ring (pharyngeal lymphoid ring, Waldeyer's lymphatic ring, or tonsillar ring) is a ringed arrangement of lymphoid organs in the pharynx. Waldeyer's ring surrounds the naso- and oropharynx, with some of its tonsillar tissue l ...

(the lymphoid tissue ring of the naso- and

oropharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its struc ...

) and Waldeyer's glands (of the eyelids).

Contribution to neuron theory

Waldeyer's name is associated in

neuroscience Neuroscience is the science, scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a Multidisciplinary approach, multidisciplinary science that combines physiology, an ...

with the "

", and for coining the term "

neuron A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa ...

" to describe the basic structural unit of the

nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes ...

. Waldeyer synthesized the discoveries by neuroanatomists (and later

Nobel Prize The Nobel Prizes ( ; sv, Nobelpriset ; no, Nobelprisen ) are five separate prizes that, according to Alfred Nobel's will of 1895, are awarded to "those who, during the preceding year, have conferred the greatest benefit to humankind." Alfr ...

winners)

Camillo Golgi Camillo Golgi (; 7 July 184321 January 1926) was an Italian biologist and pathologist known for his works on the central nervous system. He studied medicine at the University of Pavia (where he later spent most of his professional career) betwe ...

(1843–1926) and

Santiago Ramón y Cajal Santiago Ramón y Cajal (; 1 May 1852 – 17 October 1934) was a Spanish neuroscientist, pathologist, and histologist specializing in neuroanatomy and the central nervous system. He and Camillo Golgi received the Nobel Prize in Physiology or M ...

(1852–1934), who had used the

silver nitrate Silver nitrate is an inorganic compound with chemical formula . It is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides. It was once called ''lunar causti ...

method of staining nerve tissue ( Golgi's method), to formulate widely cited reviews of the theory. Waldeyer learned Spanish in order to absorb Cajal's detailed studies using Golgi's method and became his friend, mentor and promoter in the German-dominated field of microscopic anatomy. The theory was published in a series of papers in the main medical journal of Germany, '' Deutsche Medizinische Wochenschrift'', which became extremely influential. However, as Cajal points out, though Waldeyer "supported the theory with the prestige of his authority, he did not contribute a single personal observation. He limited himself to a short brilliant exposition of the objective proofs, adduced by His, Kölliker, Retzius, van Gehuchten and myself, and he invented the fortunate term ''neuron''."

Cytology and embryology

Waldeyer also studied the basophilic stained filaments which had been found to be the main constituents of

chromatin Chromatin is a complex of DNA and protein found in eukaryote, eukaryotic cells. The primary function is to package long DNA molecules into more compact, denser structures. This prevents the strands from becoming tangled and also plays important ...

, the material inside the

cell nucleus The cell nucleus (pl. nuclei; from Latin or , meaning ''kernel'' or ''seed'') is a membrane-bound organelle found in eukaryotic cells. Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, h ...

, by his colleague of

Kiel Kiel () is the capital and most populous city in the northern German state of Schleswig-Holstein, with a population of 246,243 (2021). Kiel lies approximately north of Hamburg. Due to its geographic location in the southeast of the Jutland ...

Walther Flemming Walther Flemming (21 April 1843 – 4 August 1905) was a German biologist and a founder of cytogenetics. He was born in Sachsenberg (now part of Schwerin) as the fifth child and only son of the psychiatrist Carl Friedrich Flemming (1799–18 ...

(1843–1905). Although its significance for genetics and for cell biology was still to be discovered, these filaments were known to be involved in the phenomenon of

cell division Cell division is the process by which a parent cell divides into two daughter cells. Cell division usually occurs as part of a larger cell cycle in which the cell grows and replicates its chromosome(s) before dividing. In eukaryotes, there ...

discovered by Flemming, named

mitosis In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is maintai ...

. as well as in

meiosis Meiosis (; , since it is a reductional division) is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, such as sperm or egg cells. It involves two rounds of division that ultimately ...

. He coined in 1888 the term "chromosome" to describe them. Among his many other anatomical and embryological studies, Waldeyer became known for his pioneering research on the development of

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, ...

and

hair Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and fi ...

, many of the terms he invented are still in use today. He also published the first embryological, anatomical and functional studies about the naso-oro-pharyngeal lymphatic tissue, which received his name. In 1904, he was elected as a member to the

American Philosophical Society The American Philosophical Society (APS), founded in 1743 in Philadelphia, is a scholarly organization that promotes knowledge in the sciences and humanities through research, professional meetings, publications, library resources, and communit ...

Bibliography

* Über Karyokinese und ihre Beziehungen zu den Befruchtungsvorgängen. ''Archiv für mikroskopische Anatomie und Entwicklungsmechanik'', 1888, 32: 1–122. Paper about mitosis and chromosomes. * Ueber einige neuere Forschungen im Gebiete der Anatomie des Centralnervensystems. ''Deutsche medicinische Wochenschrift'', Berlin, 1891: 17: 1213–1218, 1244–1246, 1287–1289, 1331–1332, 1350–1356. (About some new researches in the field of anatomy of the central nervous system). His most famous statement and summary of the neuron theory. * W. von Waldeyer-Hartz: ''Lebenserinnerungen''. Bonn, 1920; 2nd edition; Bonn, 1921; 3rd edition, 1922. His memoirs.

References and notes

External links

Heinrich Wilhelm Gottfried Waldeyer-Hartz
WhoNamedIt.
Short biography and bibliography
in the Virtual Laboratory of the Max Planck Institute for the History of Science {{DEFAULTSORT:Waldeyer 1836 births 1921 deaths German anatomists German neuroscientists Members of the Prussian House of Lords People from the Duchy of Brunswick History of neuroscience Corresponding members of the Saint Petersburg Academy of Sciences Foreign associates of the National Academy of Sciences University of Strasbourg faculty Members of the American Philosophical Society Members of the Royal Society of Sciences in Uppsala