(b. Posen, Germany [now Poznan, Poland], 30 July 1815; d. Kissingen, Germany, 29 August 1865)
histology, embryology, neurology.
Remak’s life has only recently been investigated in detail by Bruno Kisch. Remak was the oldest of the five children of Salomon Meyer Remak, who ran a tobacco shop and lottery office, and Friederike Caro. The family is generally thought to have been prosperous, although Alexander von Humboldt referred to them as being poor; both descriptions may well have been accurate, since changing political and economic conditions might have altered their circumstances, especially after the return of Poznan from Polish to Prussian sovereignty by the Congress of Vienna. The family were Orthodox Jews and maintained a close identification with Polish culture; Remak himself maintained both these allegiances, even after he moved to Prussia.
Remak received his earliest education at home, then attended a private school before entering the lower secondary school in Poznan. Illness forced him to interrupt his education for a year, but he returned to complete his secondary studies at the Poznan Polish Gymnasium. In 1833 he enrolled at the University of Berlin to study medicine. It was a propitious time, since Johannes Müller had just assumed the professorship of anatomy and physiology there, and Remak was able to profit from his instruction. Remak also studied under C. G, Ehrenberg, and Müller and Ehrenberg both allowed him to use their microscopes and otherwise assisted him in the independent research that he began while he was still an undergraduate. This work was itself given direction by Ehrenberg’s observations on invertebrate ganglion cells and nerve fibers and by a remark by Müller suggesting the still unproved existence of extremely fine primitive fibrils within the nerve fiber. Remak published his first studies on the fine structure of nerve tissue in 1836; this communication was reprinted with further reports in his dissertation of 1838, Observationes anatomicae et microscopicae de systematis nervosi structura.
The Observationes contained Rernak’s demonstration that the medullary nerve fibers are not hollow, as had been supposed, but rather surround a translucent substance—Remak thought that this core was flat, and therefore called it the “primitive band.” (His work on this subject was parallel to that of Purkyne, and Purkyěe’s term for this central core—which he called the “axis cylinder”—became the one that was widely accepted.) Remak also reported his discovery of the marrowless nerve fibers in the sympathetic nervous system (which he called “organic” to distinguish them from the “animal” medullary fibers of the cerebrospinal nerves) and confirmed that these fibers originate in the ganglion cells. His findings were at first criticized, especially by G. G. Valentin and Jacob Henle, but were later proved to be correct. Remak translated his work into Polish, and in so doing created a new Polish nomenclature.
The Observationes gained Remak the M.D. from the University of Berlin in January 1838; he presumably took the state examination that enabled him to practice medicine shortly thereafter. Although he had no official position, Rermak chose to stay in Müller’s laboratory after he finished his studies; he supported himself by his medical practice and by giving private lessons in microscopy (One of his first students was Albert Koelliker.) Although Remak wished to make a career in teaching, the way was barred to him, since in Prussia at that time Jews were not admitted to that profession. Remak considered emigrating to Paris, but was dissuaded by Humboldt, who urged him to continue his research. He therefore continued his investigations of nerve tissue, and in 1839 discovered ganglion cells in the human heart. This finding seemed to him to explain the relatively autonomous action of the heartbeat, which he knew to be independent of the central nervous system. He further demonstrated the small ganglia that occur in the gray nerve fibers of the lung, the larynx, the throat, and the tongue; he later found such ganglia in the wall of the urinary bladder.
In 1840 Remak turned his attention to the function of the “organic”—that is, the sympathetic—nervous system. He published articles on physiology and histology of the nervous system in general in the Encyclopädisches Wörterbuch der medicinischen Wissenschaften the following year. Other results of his most important microscopic examinations also appeared in 1841, under the title “Ueber die Entstehung der Blutkörperchen.” The terminology that Remak employed in this work is often difficult to interpret, but the main body of his discussion is concerned with the Zerschnurung (literally, “splitting by constriction”) of the nucleus with a subsequent division of the cell body—probably amitosis. Remak was to return to this subject in his later work on embryology, but it is interesting to note that as early as 1842 he was opposed to the notion that cells can be generated from a more or less homogeneous base substance.
In 1843 Remak again attempted to teach. He was falsely encouraged by the idea that the recent change of monarchs (Friedrich Wilhelm IV had become king in 1840) would be advantageous to the Prussian Jews, and against Humboldt’s advice inquired of the ministry of education whether he might be made a Dozent. His request was refused, but in March of that year—with the consent of Muller and the somewhat hesitant assistance of Humboldt—he made a direct petition to the king. and was once again rejected. Remak then turned again to research, chiefly to clinical investigations carried out in Schönlein’s laboratory, which he entered as an assistant in November.
Although pathology was now his chief concern, Remak continued to do important work on the nervous system and in embryology. In 1843 and 1844, he established the presence of extremely thin fibrils in the axis cylinder, while in the earlier year he conducted research on chicken embryos to demonstrate that the innermost portion of the germinal layer (later called the endoderm) is the site from which develops the epithelium of not only the gastrointestinal tract, but also that of the respiratory passages, as well as the parenchymas of the liver, pancreas, and thyroid. He also, in 1845, demonstrated the division of those cells in the embryo which develop into primitive muscle bundles. His chief work of pathological anatomy, Diagnostische und pothogenetische Untersuchungen, was published the same year.
Remak had by this time acquired some eminence; the introductory material to his book mentions his membership in the Leopoldina and the Senckenberg Scientific Society of Frankfurt, as well as his corresponding membership in the Warsaw Medical Society. Nevertheless, when he applied for the post of prosector of the Charité in Berlin in 1846, he was not granted it, and the position went to Rudolf Virchow, his junior by six years. At the end of 184?, however, Huntboldt and Schonlein, who was physician in ordinary to the king, succeeded in obtaining a lectureship for Remak—who was disappointed because he had hoped for a full professorship. All the daily newspapers carried the account of Remak’s first lecture, since it was the first time a Jew had taught at the University of Berlin. It may be assumed that his practice profited from the publicity; at any rate, in 1847 he married Feodore Meyer, the daughter of a Berlin banker and the next year gave up his position in Schönlein’s laboratory.
In 1848 and 1849 Remak returned to his studies of the germinal layer. He demonstrated that the medullary canal arises from the central portion of the ectoderm, while its epithelium and associated glands develop from the periphery. He then stated that the body wall and the wail of the intestine develop from the mesoderm by cleavage. In 1850 Remak published the first of the three parts of his Untersuchungen über die Entwicklung der Wirbelthiere. In it he discussed the probability that the cells in fertilized chicken eggs divide continuously; he further remarked that the structural elements of the ectoderm and the endoderm become increasingly smaller as their numbers increase. He mistakenly asserted that the spinal ganglion and nerve stem in birds are formed from the mesoderm, and he was likewise mistaken in assuming the genetic deflection of the chorda dorsalis. He correctly observed the transformation of the primitive vertebra into the permanent vertebra in the chick, although he was able to offer only a partial interpretation of the role of the medullary plate as the site from which the mesenchyme is formed—for him, its importance lay in its supplying the material of which the oviduct is formed.
It was only in 1851 that Remak recognized that the sense organs are formed from the ectoderm. He reached this conclusion as a result of the fixation of blastodiscs with acetic acid, sublimate, or chromic acid. He did not achieve true staining, however, except in a series of preparations with tincture of iodine. He reported these findings, with others, in a second part of the Untersuchungen.
By 1852 Remak was able to announce certain conclusions concerning cell division. He set aside some of his cautious earlier formulations, and asserted that the cleavage of the frog egg is due to a continuous process of division that always begins with the nucleus. He posited similar divisions, likewise starting with the cell nucleus, as occurring in somewhat later developmental stages of embryonic cells, which are again produced by cleavage. These divisions are common to almost all types of tissue, including that of the muscles, nervous system, and cartilage, as well as the epidermis, connective tissue, intestinal epithelium, and blood cells. Of particular importance was Remak’s suggestion that, contrary to Schwann’s view, the intercellular substances of the cartilage and connective tissue cannot be a cytoblastema. (It must be mentioned, however, that Remak made no specific note of mitotic cell division until 1858, when he presented an account of the formation of the blood in a five- day-old chick embryo.)
Publication of Remak’s Untersuchungen was completed in 1855. A good deal of the third part was devoted to such supplementary studies as that of the ectodermal origin of the crystalline lens, which he demonstrated in the case of fish, batrachians, birds, and mammals. He also stated that feathers, hair, and nails are ectodermal formations. He examined the mesoderm with particular care, and noted that the portion of it that borders on the medullary canal represents a rudimentary form of the vertebral canal and its associated muscles. Remak was not at this time aware of the important role of the mesoderm as the rudimentary tissue from which the blood vessels arise.
In examining the endoderm, Remak confirmed the important differences that exist between holoblastic and meroblastic eggs. He nevertheless considered that their mode of development was fundamentally the same, and in particular he stressed the epithelial origin of the glands that empty into the intestine. “The whole substance of the liver,” he wrote, “is therefore identical with the epithelium of the intestinal tube.” Remak was unable to present a convincing demonstration of the derivation of the kidney tubules from the intestinal epithelium, and his emphasis upon the supposed origin of the nerves from the mesoderm is also unsatisfactory. On the whole, however, Remak’s own assessment of the value of the Untersuchungen is an accurate one; he wrote that it established the position of histology among the sciences and “served as a foundation and stimulus for investigations of the interaction of the homologous formal constituents and heterologous tissues of the animal body.”
Remak’s first work on neurology. Über methodische Electrisierung gelähmter Müskeln, was also published in 1855. After 1856, when he lost the appointment to the chair of pathology at the University of Berlin to Virchow, Remak devoted himself entirely to his medical practice. He invented the technique of electrotherapy, which he applied successfully to his patients and described in his Galvanotherapie der Nervenund Muskelkrankheiten, which he dedicated to Humboldt and published in 1858. In 1859 he was appointed an assistant professor at the university, but this belated recognition had no effect upon his subsequent career.
Remark was often ill; there are indications that even during his first years as an assistant in Schönlein’s laboratory he had suffered from a chest ailment and had not expected to live much longer. To his sickness was added his frustration at being unable to win suitable academic appointment, so that he was often irritable and petulant in both his personal and his professional relationships. He died suddenly, while taking a rest cure.
I. Original Works. Remark’s major scientific publications are “Vorläufige Mitteilung microscopischer Beobachtungen über den inneren Bau der Cerebrospinalnerven und über die Entwicklung ihrer Formelemente,” in Müllers Archiv für Anatomie, Physiologie und wissenschaftliche Medizin (1836), 145–161; Observationes anatomicae et microscopicae de systematis nervosi structura (Berlin, 1838), his doctoral dissertation; “Ueber die Ganglien der Herznernen des Menschen und deren physiologische Bedeutung,” in Wochenschrift für die gesamte Heilkunde (1839), 149–154; “Ueber die physiologische Bedeutung des organischen Nervensystems, besonders nach anatomischen Tatsachen,” in Monatsschrift für Medizin, Augenheikunde und Chirurgie, 3 (1840), 225–265; “Ueber die Entrtehung der Blutkürperchen,” in Medizinische Zeitung, 10 (1841), 127; “Ueber den Inhalt der Nervenprimitivrohren,” in Müllers Archiv für Anatomie, Physiologie und wissenschaftliche Medizin (1843), 197–201; “Neurologische Erläuterungen,” ibid., (1844), 463–472; Ueber ein selbständiges Darmnervensystem (Berlin, 1847); and “Ueber die Funktion und Entwickelung des oberen Keimblattes im Ei der Wirbelthiere,” in Monatsberichte der Preussischen Akademie der Wissenschaften zu Berlin (Oct. 1848), 362–365.
Also see Untersuchungen über die Entwicklung der Wirbelthiere, 3 pts. (Berlin, 1850–1855); “Ueber extracellular Entstechung thierischer Zellen und über Vermehrung derselben durch Theilung,” in Müllers Archiv für Anatomie, Physiologie und wissenschaftliche Medizin (1852), 47–57; Galvanotherapie der Nerven- und Muskelkrankheiten (Berlin, 1858), also in French trans. (Paris, 1860); and “ueber die Theilung der Blutzellen beim Embryo,” in Müllers Archiv für Anatomie, Physiologie und wissenschaftliche Medizin (1958), 178–188.
II. Secondary Literature. See Arthur Hughes, A History of Cytology (London-New York, 1959), 58; Bruno Kisch, “Robert Remak,” in “Forgotten Leaders in Modern Medicine,” in Transactions of the American Philosophical Society, n.s. 44 (1954), 227–296; Leslie T. Morton, ed., Garrison and Morton’s Medical Bibliography, end ed. (London, 1961); and Julius Pagel, “Robert Remak,” in Allgemeine deutsche Biographie, 28 (Leipzig, 1889), 191–192.