People who felt sick for home were often advised to avoid experiences likely to trigger nostalgia. Music could be especially dangerous. In his Dictionary of Music, Jean-Jacques Rousseau tells us that at the palace of Versailles in the eighteenth century, it was forbidden to sing or play a tune called “Le Ranz des vaches.” This was because soldiers in the Swiss Guard were deserting their posts after hearing it. The melody was traditionally played on the horn by Swiss herdsmen as they drove their cattle to or from the pasture. When the soldiers heard the familiar mournful tune, some of them were overcome with sadness and longed to return to Switzerland. Others became physicall