Heinrich Wilhelm Gottfried von Waldeyer-Hartz
Encyclopedia
Heinrich Wilhelm Gottfried von Waldeyer-Hartz (6 October 1836, Hehlen an der Weser
Hehlen
Hehlen is a municipality in the district of Holzminden, in Lower Saxony, Germany....

, Braunschweig
Braunschweig
Braunschweig , is a city of 247,400 people, located in the federal-state of Lower Saxony, Germany. It is located north of the Harz mountains at the farthest navigable point of the Oker river, which connects to the North Sea via the rivers Aller and Weser....

, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 – 23 January 1921, Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...

) was a German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

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

 of organization of the nervous system
Nervous system
The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body. In most animals the nervous system consists of two parts, central and peripheral. The central nervous...

 and for naming the chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...

. He is also remembered in two macroanatomical
Gross anatomy
Gross anatomy is the study of anatomy at the macroscopic level. The term gross distinguishes it from other areas of anatomical study, including microscopic anatomy, which is studied on a microscopic scale, typically with a microscope....

 structures of the human body which were named after him: Waldeyer's tonsillar ring
Waldeyer's tonsillar ring
Waldeyer's tonsillar ring is an anatomical term describing the lymphoid tissue ring located in the pharynx and to the back of the oral cavity....

 (the lymphoid tissue ring of the naso-
Nasopharynx
The nasopharynx is the uppermost part of the pharynx. It extends from the base of the skull to the upper surface of the soft palate; it differs from the oral and laryngeal parts of the pharynx in that its cavity always remains patent .-Lateral:On its lateral wall is the pharyngeal ostium of the...

 and oropharynx
Oropharynx
The Oropharynx reaches from the Uvula to the level of the hyoid bone.It opens anteriorly, through the isthmus faucium, into the mouth, while in its lateral wall, between the two palatine arches, is the palatine tonsil....

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

The neuron theory

Waldeyer's name is sometimes associated in the neuroscience
Neuroscience
Neuroscience is the scientific study of the nervous system. Traditionally, neuroscience has been seen as a branch of biology. However, it is currently an interdisciplinary science that collaborates with other fields such as chemistry, computer science, engineering, linguistics, mathematics,...

to the so-called "neuron theory" and for coining the term "neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...

" to describe the basic structural unit of the nervous system. Waldeyer used the path-breaking discoveries by neuroanatomists
Neuroanatomy
Neuroanatomy is the study of the anatomy and organization of the nervous system. In contrast to animals with radial symmetry, whose nervous system consists of a distributed network of cells, animals with bilateral symmetry have segregated, defined nervous systems, and thus we can begin to speak of...

 (and later Nobel Prize
Nobel Prize
The Nobel Prizes are annual international awards bestowed by Scandinavian committees in recognition of cultural and scientific advances. The will of the Swedish chemist Alfred Nobel, the inventor of dynamite, established the prizes in 1895...

 winners) Camillo Golgi
Camillo Golgi
Camillo Golgi was an Italian physician, pathologist, scientist, and Nobel laureate.-Biography:Camillo Golgi was born in the village of Corteno, Lombardy, then part of the Austrian Empire. The village is now named Corteno Golgi in his honour. His father was a physician and district medical officer...

 (1843-1926) and Santiago Ramón y Cajal
Santiago Ramón y Cajal
Santiago Ramón y Cajal ForMemRS was a Spanish pathologist, histologist, neuroscientist, and Nobel laureate. His pioneering investigations of the microscopic structure of the brain were original: he is considered by many to be the father of modern neuroscience...

 (1852-1934), who had used the silver nitrate
Silver nitrate
Silver nitrate is an inorganic compound with chemical formula . This compound 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...

 method of staining nerve tissue (Golgi's method
Golgi's method
Golgi's method is a nervous tissue staining technique discovered by Italian physician and scientist Camillo Golgi in 1873. It was initially named the black reaction by Golgi, but it became better known as the Golgi stain or later, Golgi method.Golgi' staining was famously used by Spanish...

) to formulate a short brilliant synthesis, even though he did not contribute with any original observations.

This method allowed them to study in exquisite detail the branching processes of nerve cells (axon
Axon
An axon is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neuron's cell body or soma....

s and dendrite
Dendrite
Dendrites are the branched projections of a neuron that act to conduct the electrochemical stimulation received from other neural cells to the cell body, or soma, of the neuron from which the dendrites project...

s) and how they seemed to interconnect among themselves, forming chains and neural network
Neural network
The term neural network was traditionally used to refer to a network or circuit of biological neurons. The modern usage of the term often refers to artificial neural networks, which are composed of artificial neurons or nodes...

s which could explain the physiological
Physiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...

 mechanisms underlying the phenomena of information transfer between neurons. Waldeyer learned Spanish
Spanish language
Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...

 in order to absorb Cajal's extraordinary 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
Deutsche Medizinische Wochenschrift
The Deutsche Medizinische Wochenschrift is a German medical journal established in 1875 by Paul Börner...

, 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
Wilhelm His, Sr.
Wilhelm His, Sr. was a Swiss anatomist and professor who invented the microtome...

, Kölliker
Albert von Kölliker
Albert von Kölliker was a Swiss anatomist and physiologist.-Biography:Albert Kölliker was born in Zurich, Switzerland. His early education was carried on in Zurich, and he entered the university there in 1836...

, Retzius
Gustaf Retzius
Magnus Gustaf Retzius was a Swedish physician and anatomist who dedicated a large part of his life to researching the histology of the sense organs and nervous system.-Biography:...

, van Gehuchten
Arthur Van Gehuchten
Arthur Van Gehuchten was a Belgian anatomist, born at Antwerp. He was professor in the faculty of medicine at the University of Leuven until the eruption of the War in Europe in 1914. He moved to England and taught biology at Cambridge University until his death. Van Gehuchten is especially...

 and myself
Santiago Ramón y Cajal
Santiago Ramón y Cajal ForMemRS was a Spanish pathologist, histologist, neuroscientist, and Nobel laureate. His pioneering investigations of the microscopic structure of the brain were original: he is considered by many to be the father of modern neuroscience...

, and he invented the fortunate term neuron. " Cajal's continuing hard work on the following decade was able to prove many aspects of the neuron theory, including the directionality of synaptic transmission
Synapse
In the nervous system, a synapse is a structure that permits a neuron to pass an electrical or chemical signal to another cell...

, and ultimately Cajal won over Golgi on their dispute of the neuron doctrine vs. the syncytium theory.

Cytology and embryology

Waldeyer also studied the basophilic
Basophilic
Basophilic is a technical term used by histologists. It describes the microscopic appearance of cells and tissues, as seen down the microscope, after a histological section has been stained with a basic dye. The most common such dye is haematoxylin....

 stained filaments which had been found to be the main constituents of chromatin
Chromatin
Chromatin is the combination of DNA and proteins that make up the contents of the nucleus of a cell. The primary functions of chromatin are; to package DNA into a smaller volume to fit in the cell, to strengthen the DNA to allow mitosis and meiosis and prevent DNA damage, and to control gene...

, the material inside the cell nucleus
Cell nucleus
In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...

, by his colleague of Kiel
Kiel
Kiel is the capital and most populous city in the northern German state of Schleswig-Holstein, with a population of 238,049 .Kiel is approximately north of Hamburg. Due to its geographic location in the north of Germany, the southeast of the Jutland peninsula, and the southwestern shore of the...

, Walther Flemming
Walther Flemming
Walther Flemming was a German biologist and a founder of cytogenetics.He was born in Sachsenberg near Schwerin as the fifth child and only son of the psychiatrist Carl Friedrich Flemming and his second wife, Auguste Winter...

 (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
Cell division is the process by which a parent cell divides into two or more daughter cells . Cell division is usually a small segment of a larger cell cycle. This type of cell division in eukaryotes is known as mitosis, and leaves the daughter cell capable of dividing again. The corresponding sort...

 discovered by Flemming, named mitosis
Mitosis
Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing roughly...

. as well as in meiosis
Meiosis
Meiosis is a special type of cell division necessary for sexual reproduction. The cells produced by meiosis are gametes or spores. The animals' gametes are called sperm and egg cells....

. He coined in 1888 the term “chromosome” (1888) to describe them.

Among his many other anatomical and embryological studies, Waldeyer became known for his pioneering research on the development of teeth and hair
Hair
Hair is a filamentous biomaterial, that grows from follicles found in the dermis. Found exclusively in mammals, hair is one of the defining characteristics of the mammalian class....

, 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.

Ethics

Waldeyer, like other members of his University, was a fierce opponent to the admission of women into medical studies.
He used pseudo-anthropological evidence to conclude that women's brains being smaller, they therefore had fewer brain cells and thus fewer intellectual capacity.

External links

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