Hugo von Mohl
Encyclopedia
Hugo von Mohl was a German
botanist from Stuttgart
.
He was a son of the Württemberg
statesman Benjamin Ferdinand von Mohl (1766–1845), the family being connected on both sides with the higher class of state officials of Württemberg. While a pupil at the gymnasium he pursued botany and mineralogy in his leisure time, till in 1823 he entered the University of Tübingen. After graduating with distinction in medicine he went to Munich, where he met a distinguished circle of botanists, and found ample material for research.
This seems to have determined his career as a botanist, and he started in 1828 those anatomical investigations which continued till his death. In 1832 he was appointed professor of botany in Tübingen, a post which he never left. Unmarried, his pleasures were in his laboratory and library, and in perfecting optical apparatus and microscopic preparations, for which he showed extraordinary manual skill. He was largely a self-taught botanist from boyhood, and, little influenced in his opinions even by his teachers, preserved always his independence of view on scientific questions. He received many honours during his lifetime, and was elected foreign fellow of the Royal Society
in 1868.
Mohl's writings cover a period of forty-four years; the most notable of them were republished in 1845 in a volume entitled Vermischte Schriften (For lists of his works see Botanische Zeitung, 1872, p. 576, and Royal Soc. Catalogue, 1870, vol. iv.) They dealt with a variety of subjects, but chiefly with the structure of the higher forms, including both rough anatomy and minute histology
. The word protoplasm
was his suggestion; the nucleus had already been recognized by R Brown
and others; but Mohl showed in 1844 that the protoplasm is the source of those movements which at that time excited so much attention.
He recognized under the name of primordial utricle the protoplasmic lining of the vacuolated cell, and first described the behaviour of the protoplasm in cell division. These and other observations led to the overthrow of Schleiden
's theory of origin of cells by free-cell-formation. His contributions to knowledge of the cell-wall were no less remarkable; he held the view now generally adopted of growth of cell-wall by apposition. He first explained the true nature of pits, and showed the cellular origin of vessels and of fibrous cells; he was, in fact, the true founder of the cell theory. Clearly the author of such researches was the man to collect into one volume the theory of cell-formation, and this he did in his treatise Die vegetabilische Zelle (1851), a short work translated into English (Ray Society, 1852).
Mohl's early investigations on the structure of palms, of cycad
s, and of tree ferns permanently laid the foundation of all later knowledge of this subject: so also his work on Isoetes (1840). His later anatomical work was chiefly on the stems of dicotyledon
s and gymnosperm
s; in his observations on cork and bark he first explained the formation and origin of different types of bark
, and corrected errors relating to lenticels. Following on his early demonstration of the origin of stomata (1838), he wrote a classical paper on their opening and closing (1850).
In 1843 he started the weekly Botanische Zeitung in conjunction with Schlechtendal
, which he edited jointly till his death. He was never a great writer of comprehensive works; no text-book exists in his name, and it would indeed appear from his withdrawal from co-operation in Hofmeister's Handbuch that he had a distaste for such efforts. In 1850, he was elected a foreign member of the Royal Swedish Academy of Sciences
. In his latter years his productive activity fell off, doubtless through failing health, and he died suddenly at Tübingen
on 1 April 1872.
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...
botanist from Stuttgart
Stuttgart
Stuttgart is the capital of the state of Baden-Württemberg in southern Germany. The sixth-largest city in Germany, Stuttgart has a population of 600,038 while the metropolitan area has a population of 5.3 million ....
.
He was a son of the Württemberg
Württemberg
Württemberg , formerly known as Wirtemberg or Wurtemberg, is an area and a former state in southwestern Germany, including parts of the regions Swabia and Franconia....
statesman Benjamin Ferdinand von Mohl (1766–1845), the family being connected on both sides with the higher class of state officials of Württemberg. While a pupil at the gymnasium he pursued botany and mineralogy in his leisure time, till in 1823 he entered the University of Tübingen. After graduating with distinction in medicine he went to Munich, where he met a distinguished circle of botanists, and found ample material for research.
This seems to have determined his career as a botanist, and he started in 1828 those anatomical investigations which continued till his death. In 1832 he was appointed professor of botany in Tübingen, a post which he never left. Unmarried, his pleasures were in his laboratory and library, and in perfecting optical apparatus and microscopic preparations, for which he showed extraordinary manual skill. He was largely a self-taught botanist from boyhood, and, little influenced in his opinions even by his teachers, preserved always his independence of view on scientific questions. He received many honours during his lifetime, and was elected foreign fellow of the Royal Society
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...
in 1868.
Mohl's writings cover a period of forty-four years; the most notable of them were republished in 1845 in a volume entitled Vermischte Schriften (For lists of his works see Botanische Zeitung, 1872, p. 576, and Royal Soc. Catalogue, 1870, vol. iv.) They dealt with a variety of subjects, but chiefly with the structure of the higher forms, including both rough anatomy and minute histology
Histology
Histology is the study of the microscopic anatomy of cells and tissues of plants and animals. It is performed by examining cells and tissues commonly by sectioning and staining; followed by examination under a light microscope or electron microscope...
. The word protoplasm
Protoplasm
Protoplasm is the living contents of a cell that is surrounded by a plasma membrane. It is a general term of the Cytoplasm . Protoplasm is composed of a mixture of small molecules such as ions, amino acids, monosaccharides and water, and macromolecules such as nucleic acids, proteins, lipids and...
was his suggestion; the nucleus had already been recognized by R Brown
Robert Brown (botanist)
Robert Brown was a Scottish botanist and palaeobotanist who made important contributions to botany largely through his pioneering use of the microscope...
and others; but Mohl showed in 1844 that the protoplasm is the source of those movements which at that time excited so much attention.
He recognized under the name of primordial utricle the protoplasmic lining of the vacuolated cell, and first described the behaviour of the protoplasm in cell division. These and other observations led to the overthrow of Schleiden
Matthias Jakob Schleiden
Matthias Jakob Schleiden was a German botanist and co-founder of the cell theory, along with Theodor Schwann and Rudolf Virchow....
's theory of origin of cells by free-cell-formation. His contributions to knowledge of the cell-wall were no less remarkable; he held the view now generally adopted of growth of cell-wall by apposition. He first explained the true nature of pits, and showed the cellular origin of vessels and of fibrous cells; he was, in fact, the true founder of the cell theory. Clearly the author of such researches was the man to collect into one volume the theory of cell-formation, and this he did in his treatise Die vegetabilische Zelle (1851), a short work translated into English (Ray Society, 1852).
Mohl's early investigations on the structure of palms, of cycad
Cycad
Cycads are seed plants typically characterized by a stout and woody trunk with a crown of large, hard and stiff, evergreen leaves. They usually have pinnate leaves. The individual plants are either all male or all female . Cycads vary in size from having a trunk that is only a few centimeters...
s, and of tree ferns permanently laid the foundation of all later knowledge of this subject: so also his work on Isoetes (1840). His later anatomical work was chiefly on the stems of dicotyledon
Dicotyledon
The dicotyledons, also known as dicots, are a group of flowering plants whose seed typically has two embryonic leaves or cotyledons. There are around 199,350 species within this group...
s and gymnosperm
Gymnosperm
The gymnosperms are a group of seed-bearing plants that includes conifers, cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos , meaning "naked seeds", after the unenclosed condition of their seeds...
s; in his observations on cork and bark he first explained the formation and origin of different types of bark
Bark
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...
, and corrected errors relating to lenticels. Following on his early demonstration of the origin of stomata (1838), he wrote a classical paper on their opening and closing (1850).
In 1843 he started the weekly Botanische Zeitung in conjunction with Schlechtendal
Diederich Franz Leonhard von Schlechtendal
Diederich von Schlechtendal was a German botanist born in Xanten. He was Professor of Botany and Director of the Botanical Gardens at the Martin Luther University of Halle-Wittenberg from 1833 until his death in 1866, and Editor of the botanical journal Linnaea.His most important work was in...
, which he edited jointly till his death. He was never a great writer of comprehensive works; no text-book exists in his name, and it would indeed appear from his withdrawal from co-operation in Hofmeister's Handbuch that he had a distaste for such efforts. In 1850, he was elected a foreign member of the Royal Swedish Academy of Sciences
Royal Swedish Academy of Sciences
The Royal Swedish Academy of Sciences or Kungliga Vetenskapsakademien is one of the Royal Academies of Sweden. The Academy is an independent, non-governmental scientific organization which acts to promote the sciences, primarily the natural sciences and mathematics.The Academy was founded on 2...
. In his latter years his productive activity fell off, doubtless through failing health, and he died suddenly at Tübingen
Tübingen
Tübingen is a traditional university town in central Baden-Württemberg, Germany. It is situated south of the state capital, Stuttgart, on a ridge between the Neckar and Ammer rivers.-Geography:...
on 1 April 1872.