section_path: Years in the Dutch Republic (1735–38)/Doctorate
section_name: Doctorate
paragraph_text: Doctorate
  
  His relations with Nils Rosén having worsened, Linnaeus accepted an invitation from Claes Sohlberg, son of a mining inspector, to spend the Christmas holiday in Falun, where Linnaeus was permitted to visit the mines.
  
  In April 1735, at the suggestion of Sohlberg's father, Linnaeus and Sohlberg set out for the Dutch Republic, where Linnaeus intended to study medicine at the University of Harderwijk while tutoring Sohlberg in exchange for an annual salary. At the time, it was common for Swedes to pursue doctoral degrees in the Netherlands, then a highly revered place to study natural history.
  
  On the way, the pair stopped in Hamburg, where they met the mayor, who proudly showed them a supposed wonder of nature in his possession: the taxidermied remains of a seven-headed hydra. Linnaeus quickly discovered the specimen was a fake, cobbled together from the jaws and paws of weasels and the skins of snakes. The provenance of the hydra suggested to Linnaeus that it had been manufactured by monks to represent the Beast of Revelation. Even at the risk of incurring the mayor's wrath, Linnaeus made his observations public, dashing the mayor's dreams of selling the hydra for an enormous sum. Linnaeus and Sohlberg were forced to flee from Hamburg.
  
  Linnaeus began working towards his degree as soon as he reached Harderwijk, a university known for awarding degrees in as little as a week. He submitted a dissertation, written back in Sweden, entitled Dissertatio medica inauguralis in qua exhibetur hypothesis nova de febrium intermittentium causa, in which he laid out his hypothesis that malaria arose only in areas with clay-rich soils. Although he failed to identify the true source of disease transmission, (i.e., the Anopheles mosquito), he did correctly predict that Artemisia annua (wormwood) would become a source of antimalarial medications.
  
  Within two weeks he had completed his oral and practical examinations and was awarded a doctoral degree.
  
  That summer Linnaeus reunited with Peter Artedi, a friend from Uppsala with whom he had once made a pact that should either of the two predecease the other, the survivor would finish the decedent's work. Ten weeks later, Artedi drowned in the canals of Amsterdam, leaving behind an unfinished manuscript on the classification of fish.