'Maladie du pays' or 'mal du pays' are French terms for homesickness which recall its perception and treatment by many, from the late 17th century to the late 19th, as a potentially dangerous nervous disorder. In 1678 physician Johannes Hofer coined the term 'nostalgia' for the condition, which became most widely diagnosed in soldiers fighting abroad, far from home and exposed to relentless psychic trauma. The common presence of Swiss mercenaries across Europe at the time led some to term this disorder 'the Swiss illness', often seen as a precursor to more serious mental derangement and occasionally, as in Frankenstein's case, suicidal tendencies.
The Rhone is one of Europe's major rivers, running from a glacier in the Swiss Alps through south-eastern France, and into the Mediterranean Sea.
Craig Lambert's historical overview 'Hypochondria of the Heart', Harvard Magazine, (2001)