Academic Career – Gathering of Material to Benefit the Art of Medicine

Linnaeus spent more than three years (1735–1738) abroad, primarily in Holland. Whether he was to be a teacher or a medical practitioner, he would need a degree, and he did not have one. He had not taken a doctorate in medicine. In August 1733 he began to write a dissertation on the cause of intermittent fever. He would later finish it and use the material in Holland to attain his doctorate. It was possible to take a doctoral degree at Lund and Uppsala, but only a foreign degree was considered sufficient. Holland enjoyed a reputation during the 18th century as being the home of medical science. Linnaeus took his doctorate at Harderwijk in 1735 with the dissertation Hypothesis nova de febrium intermittentum causa. His time there was primarily devoted to botany and was important for establishing an international network. Linnaeus also attracted considerable international acclaim for his knowledge of botany. In terms of his medical career the stay was important because he won the close friendship and respect of a number of prominent individuals in medical science at the time. Leyden was where the charismatic Herman Boerhaaven (1668–1738) worked, a scientist whose contributions involved the mechanisms of inflammation, the kinetics of blood, and the importance of diet for the condition of blood.

Linnaeus had a great many ideas about the genesis of diseases. They involve causal relationships of a rather general nature. The importance of hygiene, diet, breastfeeding, etc. relates to general medical views rooted in his own observations and how he makes use of the observations of other scientists. To some extent Linnaeus also takes up certain specific diseases or rather the emergence of specific symptoms.  One such symptom was intermittent fever, that is, what we call “ague.” As mentioned, this was the subject of his dissertation. The word ague brings to mind malaria, of course, and malaria did occur in Sweden in the 18th century, not least in the valley surrounding Lake Mälaren. Linnaeus could not have known that malaria is caused by parasites and that these parasites spread to humans via mosquitoes. This was established by the British tropical physician Ronald Ross and the French military physician Charles Louis Alphonse Laveran in the 1880s (which won them the Nobel Prize). But among Linnaeus’ views about the causes of diseases we find the assumption Exanthema viva, which stands for the notion that contagious diseases are caused by the invasion of the human body by tiny organisms. Linnaeus was not alone in holding this view. The Italian Lancisis wrote in 1717 regarding malaria and mosquitoes: “not solely via bites and stings but primarily thereby they inoculate their malicious fluids in our blood.” The explanation Linnaeus gave for ague varied in different periods, but what was central to his assumption was the proximity of standing water, moisture, and bad air (the literal meaning of mal-aria is “bad air”) which promoted the development of various organisms such as fungi and moulds. If the technology of microscopes had been more advanced in Linnaeus’ day, he might have come closer to the cause of malaria. With the benefit of hindsight, we can nevertheless establish with some admiration how observation and aggregated experience could lead remarkably close to an understanding of the cause of a disease.

When Linnaeus returned from Holland he settled in Stockholm to set up a medical practice. At first it was hard to find patients. This is not surprising considering that he was rather inexperienced in practical medicine. Well respected as Princeps Botanicorum (the Prince of Botany), he now encountered a certain lack of trust as a medical practitioner. When patients did not seek him out, he went looking for them. He contacted the young “gallants” who frequented the city’s coffee houses on Riddartorget (Nobility Square) – whiling away their time with food and wine. Pox and ague were going around. His advice became popular. He gradually had more patients than he could deal with. His reputation as a skilled physician spread widely, and he was consulted in the higher circles. Linnaeus had a tremendous ability to acquire patrons. Count Carl Gustaf Tessin, marshal of the realm, heard about Linnaeus’ success abroad and arranged support for him until Linnaeus could obtain a permanent position. Tessin maintained that the Estates should regard it as a pleasure to further a Swede who had distinguished himself so much abroad. Linnaeus applied to the Estates for funding until a permanent position was available. He put forward his fame in England and Holland, his work with Historia naturalia, and hinted that he had been offered a number of attractive positions abroad. Tessin championed his cause, pointing out the risk that Linnaeus might leave the country. The application was granted. Tessin also offered Linnaeus lodging in the Tessin home in return for Linnaeus eating lunch with and instructing  him in scientific subjects. In this way he came into contact with members of parliament who met in Tessin’s home and became their personal physician. A result of this was that Admiral Ankarcrona offered Linnaeus the position of physician to the admiralty, which was vacant (1739). Linnaeus was appointed to the post and received 2700 daler in regular annual income. That was a great deal of money compared with what Linnaeus had hoped for. “From the prosperity that God and Count Tessin have put me in, I live very satisfactorily, well, and amply,” he wrote.

Linnaeus’ good contacts with high political officials were reflected in the fact that the Collegium Medicum did not bother to point out that Linnaeus had not taken the examination before the Collegium that was required of a physician who had acquired his doctorate abroad. It was probably considered somewhat presumptuous to call in for an examination such an acclaimed scientist and a personage of the social position that Linnaeus enjoyed.

Linnaeus’ workload was enormous. He had many patients in his private practice, and his medical duties at the admiralty (the navy hospital on Skeppsholmen had 100–200 places, the assistance of a barber-surgeon and an assistant surgeon). He carefully monitored the effects of the medicines he prescribed, planted a garden for medicinal plants, and performed autopsies. Besides this, he held a number of public lectures and maintained a large network of contacts with foreign and Swedish scientists. The Swedish researchers and science enthusiasts included Jonas Ahlström, Anders J von Höpken, Baron S C Bjelke, and Captain Mårten Triwald. Together with these gentlemen, in June 1739, in the Auditorio illustri at the House of Nobility, he established the Royal Swedish Academy of Sciences. Linnaeus served as the Academy’s president for the first few months.

In the context of ”Linnaeus as a physician” it is necessary also to draw attention to another prominent figure of the day – Nils Rosén. He too was a protégé of Professor Stobaeus. Rosén was abroad when Linnaeus arrived in Uppsala. When Rudbeck was granted a leave of absence, Rosén was appointed adjunctus medicinae, and was to take up his duties as soon as he returned from his stay abroad.

_{Rosén wrote a number of textbooks: Compendium anatomicum came out in 1736-37. The book Hus- och Reseapotheque (Apothecary for home and travel) appeared in 1765.
Source: Compendium anatomicum: image from the 1736 original. Hus- och Reseapotheque:Facsimile edition, 1970, Bokförlaget Rediviva.}

Relations between Linnaeus and Rosén have been described as being occasionally strained. Rosén is seen as having conspired to obstruct Linnaeus’ career. His motive may have been the competition to succeed Rudbeck. Rosén returned from his sojourn abroad in 1731 and taught anatomy and practical medicine to satisfied students. He was generally known to be skilled in practical medicine and botany. Medical instruction in anatomy and botany was done by Rosén, according to the catalogue, whereas Professor Roberg was supposed to lecture on physiology, characteres morborum, and chemistry. Roberg was old and feeble, so Rosén had taken over this teaching as well.

The problem of the inferior instruction carried out by the elderly professors Rudbeck and Roberg was ultimately solved. Rudbeck died suddenly on March 23, 1740, and after some prodding from the Chancellor, Roberg was persuaded to retire. Thereby the professorships in botany, anatomy, and other subjects fell vacant.

The professorships in medicine vacated by Rudbeck and Roberg were now open for applications, and Linnaeus submitted his. Of course, Rosén did so as well, as did Rosén's protégé, the medical adjunct J G Wallerius. Some problems arose regarding the appointment. Rosén was ranked highest to succeed Rudbeck. Linnaeus had superior scientific qualifications, but mainly in botany, while Rosén had qualifications from having carried out Rudbeck's teaching for nine years and above all was skilled in the field of anatomy. Linnaeus contacted Tessin, who put in a good word for him with the Chancellor. But the University Board demanded that Linnaeus pass an examination for the professorship. The Chancellor maintained that this was unnecessary. The Board opposed the Chancellor, but there was disunity within the Board.  Wallerius then moved that there was reason to scrutinize Linnaeus’ doctoral dissertation. Linnaeus adduced a memorandum listing all of his publications together with the tremendously supportive letters he had received from a number of internationally renowned scientists. The result of this was that it was deemed unnecessary for Linnaeus to undergo questioning but that Wallerius would have to instead. Wallerius submitted a dissertation that in principle was a comprehensive critique of the works Linnaeus had written. In February 1741 this dissertation was defended publicly. There was a large crowd in attendance, and the proceedings were stormy, to say the least.

In the end it was all cleared up, and Linnaeus and Rosén each received a professorship. In May 1741 Linnaeus was appointed professor of theoretical and practical medicine at Uppsala, but after less than a year (Jan. 1742) the University Board took the initiative to swap the subjects of Rosén's and Linnaeus’ professorships. Linnaeus was to lecture on botany and materia medica, among other subjects, while Rosén took charge of anatomy, physiology, etiology, and the science of preparing medicines.