Anders Adolf Retzius
Biography of Anders Adolf Retzius
Anders Adolf Retzius holds a distinguished place among nineteenth century scientists for his contributions to comparative anatomy, histology, and anthropology. He played a prominent role in the development of biological sciences in Scandinavia, and was one of those who guided Swedish biology and medicine into scientific channels – against the strong influence of the speculative Naturphilosophie prevalent in many of the German universities.
Anders Adolf Retzius was the brother of the physician Magnus Kristian Retzius (1795-1871). His father, Anders Johan Retzius (1742-1821), was professor of natural history at the University of Lund. When the young Retzius entered the University of Lund in 1812, he came under the influence of Arvid Henrik Florman (1761-1840), professor of anatomy, who initiated him into the methods of dissection and careful observation.
In 1816 Retzius spent a year at Copenhagen with the anatomist Ludwig Levin Jacobson (1783-1843), the physicist Hans Christian Örsted (1777-1851), and the zoologist Johan Christopher Hagemann Reinhardt (1776-1845). After his return Retzius finished his medical studies at Lund, passing his examination in 1817 and becoming "medicine licentiat" and "kirurgie magister" in 1818. In 1819 he obtained his medical doctorate with a dissertation on the anatomy of cartilaginous fishes, especially the dogfish and the ray, Observationes in anatomiam chondropterygium praecipue squali et rajae generum.
Retzius subsequently served as a military physician, first in Schonen, later in Jämtland, and in 1823 was appointed theoretices professor of veterinary science at the Stockholm Veterinary Institution. In 1824, supported by Jöns Jakob Berzelius (1779-1848), he also became professor extraordinary of anatomy at the Karolinska Medico-Kirurgiska Institutet.
In 1830 Retzius was awarded the additional post of inspector of the Karolinska Institutet and was, besides Berzelius, the strongest personality in its early development. In 1840, being appointed full professor at Karolinska, he resigned his post at the Veterinary Institution and until his death devoted all his time to the two posts he held at the Karolinska Institutet.
Retzius’ scientific work began with comparative anatomy, which he pioneered in Sweden and made a subject of medical training. During his studies for his inaugural dissertation, he discovered the internal organ of elasmobranch fishes which is – as was shown later – homologous with the adrenal cortex of higher animals. A few years later, in 1822, he studied in detail a still more primitive vertebrate, the slime eel (Myxine glutinosa), a curious animal placed by previous naturalists in such different groups as molluscs, fishes, and even amphibians. Retzius described in two brief but significant studies (1822 and 1824) its complicated cartilaginous cranium, digestive system, and pronephric ducts.
The pronephros itself was discovered later by Johannes Peter Müller (1801-1858). Retzius also described a gland shown later (also by Müller) to be homologous with the adrenal organ of higher forms. Retzius work on the slime eel was related to his research on Amphioxis, the only link between vertebrates and invertebrates. Retzius noticed several new features of this animal. He informed Müller of his findings and, because his vision was deteriorating, invited Müller to accompany him to Bohuslän, where they could investigate the living animals in detail. In just twelve days in September 1841 the investigation of Amphioxus’ morphology was completed, and Müller presented the results to the Berlin Academy of Sciences on December 6.
Traveller in science
In the period 1824-1835 Retzius made several journeys to other parts of Europe and to England, where he met many scientists and participated in several scientific meetings. At a memorable meeting of German naturalists and physicians in Berlin in 1828, Retzius invited Karl Ernst von Baer (1792-1876) to use a dog to demonstrate the mammalian ovum, his famous discovery which had been made public at the beginning of that year but had noe been mentioned to Baer by any other participant at the meeting.
In 1833, after a journey to England, France, Germany, and Austria, Retzius attended one of the annual congresses at Breslau. While there he worked with Jan Evangelista Purkinje (1787-1869), who introduced him to the use of the microscope and the techniques of preparing tissues for microscopic observations, in particular hard tissues, bone, and teeth…
This new knowledge and practical experience marked a turning point in Retzius’ research, for after his return to Stockholm he began a series of microscopic studies – the most important of which were those of the structure of the teeth of several animal species. His work and that of Purkinje on this topic had a great effect and stimulated others to study the structure and development of teeth.
About 1840 it became evident that Retzius’ eyesight had greatly deteriorated, and he had to abandon microscopic studies. For the last two decades of his life, he turned to gross anatomy, chiefly of the skeletal, circulatory, and nervous systems; to topographical anatomy; and to physical anthropology.
Retzius’ most important work seems to have been in anthropology, where, following Johann Friedrich Blumenbach (1752-1840), he attempted to work out a way of classifying human ethnic groups according to their physical characters. After the discovery of numerous human remains in prehistoric graves in Scandinavia, Retzius noticed during their investigations considerable variation in the shape of the cranium. He extended his research to other European ethnic groups and found that human skulls could be divided, according to the proportion of length to breadth, into long (dolicocephalic) and short (brachycephalic), each race having a constant ratio between the breadth and length (cephalic index). Another division could be made according to the shape of the facial bones: orthognathous and prognathous. This research was taken seriously decades into the 20th century.
The value of this work is not so much in Retzius’ conclusions – in the division of populations according to to their craniometric charactes – but in his demonstrating the possibility of quantitative expression of different patterns of bodily forms and their mathematical treatment. Craniometric and anthropometric methods were soon widely adopted and developed, and new indexes were introduced. Thus there emerged a new branch of science – physical antrhopology.
Anders Retzius remarried 1835; his second wife, the mother of Magnus Gustav Retzius (1842-1919), was Emilia Sofia Wahlberg, sister of the botanist and entomologist Peter Fredrik Wahlberg (1800-1877).
Most of his important works were also published in German, in Archiv für Anatomie und Physiologie (1826-1849), in Notizen aus dem Gebiete der Natur- und Heilkunde, or Archiv für Anatomie, Physiologie und wissenschaftliche Medicin (1837).
Anders Adolf retzius was a member of many learned societies both at home and abroad.