Matthias Jakob Schleiden

German biologist

• Born: April 5, 1804; Free Imperial City of Hamburg (now Hamburg, Germany)
• Died: June 23, 1881; Frankfurt am Main, Germany

Nineteenth-century biologist Matthias Jakob Schleiden contributed to the concept of cell theory through his observations that plants are composed of cells, and that such cells represent the fundamental structure of plants.

Primary field: Biology

Specialty: Cellular biology

Early Life

Matthias Jakob Schleiden was born April 5, 1804 in Hamburg, to Andreas Benedikt Schleiden and Eleanore Bergeest Schleiden. His father was a prominent physician trained at the University of Jena. His younger brother, Karl Heinrich Schleiden, later became a prominent theologian after training in Jena. Schleiden’s earliest interests were in the field of botany.

Schleiden entered the university at Heidelberg in 1824, where he began studying law. After graduating in 1827, he returned to Hamburg and established a law practice in that city. It is known that Schleiden attempted unsuccessfully to die by suicide in 1831 after suffering for a time from severe depression. When he recovered, he decided to pursue his true interest, the study of medicine, and he enrolled in the University of Göttingen. Schleiden studied with German chemist Friedrich Stromeyer. Among his classmates were Robert Bunsen, a pioneer in photochemistry, and philosopher Jakob Fries. Fries believed in a mechanistic approach to nature, a worldview that Schleiden espoused much of his life.

Schleiden’s interest in the sciences was in informed Fries’ Mathematical Philosophy of Nature (1822). Like English physicist Isaac Newton, Fries argued that an understanding of nature required an analytical approach. Schleiden concluded that to understand nature he would have to immerse himself in mathematics, and he began working with German mathematician Carl Friedrich Gauss. Schleiden spent his final two years at Göttingen working with Gauss, who helped expand his understanding of the subject.

After graduating with a medical degree in 1834, Schleiden accepted a position in the laboratory of physiologist Johannes Müller at the Humboldt University in Berlin.

Life’s Work

Müller’s interest was primarily the study of optics. As a student, he had observed the function of the optic nerve and its response to light. Müller was considered among the founders of the scientific method developed in Germany, and his 1833 physiology textbook, Handbuch der Physiologie des Menschen (Handbook of human physiology) influenced generations of physiologists. Schleiden worked with Müller developing his cell theory of plants—namely, that they were composed of individual cells carrying out the specific functions of the plant.

Among Müller’s students was Theodor Schwann, who extended Schleiden’s cell theory to include the cellular structure of animals as well. Both Schleiden and Schwann, however, mistakenly believed cell reproduction resulted from the initial formation of a cytoblast (nucleus) around which the cell substance would crystallize.

Schleiden published his observations on plants, “Beiträge zur Phytogenesis”(Contributions to plant origins),” in 1838. Schleiden began the work by disparaging many of his forerunners in the field. Indeed, his contemporaries often described him as being arrogant. This view is supported by Schleiden’s descriptions of the work of prominent biologists, such as that of French biologist François-Vincent Raspail, as not being worthy of study. In his article, Schleiden presented his model of cell origins involving the cytoblast. To his credit, Schleiden did pay tribute to earlier work by Robert Brown in his description of the nucleus—the organelle that Schleiden renamed the “cytoblast” in his article.

In 1839, Schleiden received a PhD in botany from the University of Jena, where he subsequently accepted a position as an assistant professor. He continued his study of plants, publishing Principles of Scientific Botany in 1842, which encompassed his earlier work with Müller and his work at Jena. Schleiden also attempted to incorporate his views on plant evolution into the book.

Although Schleiden’s research interests were within the discipline of botany, and he was in charge of the botanical gardens at the university, he preferred thinking of himself as one who studied the anatomy and physiology of plants. To Schleiden, a botanist was little more than a plant librarian, chiefly interested in naming, collecting, and classifying plants.

Schleiden remained at the University of Jena some twenty years, eventually being promoted to vice president and dean. In 1850, he began to lecture on anthropology. Perhaps due to overwork, or perhaps the result of the same psychological issues that had plagued him in his youth, Schleiden again suffered increasingly from depression. His work on cell origins had also come under attack, most notably by physiologist Robert Remak. Remak’s work dealt primarily with the replication of embryonic cells in the chicken, and his conclusion that replication was through a process of binary fission was at odds with that of Schwann’s (and by extension Schleiden’s) description of cytoplasmic crystallization.

In 1862, Schleiden resigned from his position at Jena, and after a brief sojourn to Dresden, accepted a post as professor of botany and anthropology at a university in present-day Estonia. This was likely in part the result of Schleiden’s relationship with Fries. Schleiden had been increasingly including concepts of physical anthropology into his lectures at Jena, often with the mechanistic view of nature originally described by Fries in 1822. Schleiden was also an early advocate of English naturalist Charles Darwin’s work and was in agreement with Darwin’s views on natural selection being central to the process of evolution.

Schleiden remained in Dorpat through 1864, resigning as his lectures came into increasing conflict with the Russian church. After his retirement, he lived in several towns throughout Germany, including Dresden, Darmstadt, and Wiesbaden. He died on June 23, 1881, while residing in Frankfurt am Main, Germany, in the middle of work on a treatise describing the role of the horse in civilization.

Impact

Schleiden’s hypothesis that plants were composed of cells, and that plant functions were carried out by the cells of which they were composed, was part of what became known as cell theory. His colleague in Müller’s laboratory, Theodor Schwann, came to similar conclusions in his studies of animal cells. Schleiden and Schwann were as commonly linked in biology as James Watson and Francis Crick were in their discovery of DNA structure over a century later.

It was for his observation of cells in plants that Schleiden received acclaim. However, his belief that cells arose from what he termed the cytoblast, in which vesicles gradually formed around the nucleus as the cell matured, served only to confuse scientists attempting to study cell division. Further, Schleiden’s model was shortly afterwards adapted by Schwann for his own hypothesis explaining the replication of animal cells—the cytoblast around which the rest of the cell assembles.

The first evidence that neither model was correct came about several years later when Austrian botanist Franz Unger and Swiss botanist Karl von Nageli each correctly described the process of cell division in plants.

Bibliography

Alberts, Bruce, et al. Essential Cell Biology. New York: Garland Science, 2009. Print. College-level introduction to the cell. Highlighted with numerous photographs, the book provides a thorough description of cell structure and function in both plants and animals.

Harris, Henry. The Birth of the Cell. New Haven, CT: Yale UP, 1999. Print. Presents a history of cell biology with an emphasis on the personalities of those who developed its history.

---. The Cells of the Body: A History of Somatic Cell Genetics. Cold Spring Harbor: Cold Spring Harbor Lab P, 1995. Print. Provides a history of cytogenetics and the role played by individuals who coined the modern terms common in cell biology.