The first global map of the distribution of human diseases: Friedrich Schnurrer's 'Charte über die geographische Ausbreitung der Krankheiten' (1827).

The practice of global cartographic representation of diseases dates from the first third of the nineteenth century, that is, from a time when, in the context of largescale exploration of the physical world, naturalists such as Alexander von Humboldt (1769-1859) devised the conceptual means for such visual representation, namely, the technique of isotherms.' By means of these, a coherent, geographical distribution of physical parameters could be visualized. Leonhard Ludwig Finke's (1747-1837) early, three-volume Versuch einer allgemeinen medicinisch-praktischen Geographie (Essay on General Medico-Practical Geography) was not accompanied by any cartographic representations (although he may have attempted such a map).2 Yet disease maps were published before 1830, the year commonly associated with the emergence of a widespread interest in medical geography, when a cholera epidemic threatened Europe.3 In 1827, the Swabian physician Friedrich Schnurrer (1784-1833), Amtsarzt (public health officer) in Vaihingen on the Enz (near Stuttgart), presented what is believed to be the first global 'Charte iiber die geographische Ausbreitung der Krankheiten' (Map of the geographical Distribution of Diseases).4 The map is here interpreted as