The International Society of Ethnopharmacology organized its 13th Congress in Graz (Austria), last September. In the current context of interest in Chinese medicine, the main theme of the conference was the Silk Road. The Scientific Director of the Institute, Alain Touwaide, was invited to deliver a plenary lecture on "The Silk Road as a Knowledge Road".
Proposing a stratigraphy of the long and often changing history of the Silk Road, which spanned more than five millennia, from the 4th millennium BCE to the 16th century CE, Touwaide focused on a dozen of layers in order to detect the presence of Far East materia medica among Mediterranean populations, together with a knowledge (or traces of it) going back to the places to which these products were native. Preliminary results are significant: no native knowledge seems to have been explicitly and faithfully transmitted, most probably because the Silk Road stretched for thousands of miles and crossed many populations. From one segment to another, knowledge may have been lost, transformed and adapted, contrary to the products, which were carefully handled down along the road (since they were the essence, the raison d'etre of the Silk Road).
However, some remains of the original knowledge of the materia medica traded along the Silk Road can be identified. A reference to pepper made in the Hippocratic collection as the medicine used to treat eye pathologies may be one such remain. Ginger offers another case of possible persistence of an element of non-native knowledge. In the most important work of Classical Antiquity on materia medica (De materia medica by Dioscorides, 1st century CE), it is considered warming and digestive. Characteristically, such properties correspond pretty well to those of ginger's rhizome in Chinese medicine.
Resemblances such as these should not lead to the premature conclusion that uses and knowledge about medicinal plants were rather stable along the Silk Road in spite of the distance and the multiple relays. Ginger would immediately contradict such possible opinion, as Dioscorides himself stated that it was typical of Arabia (the coasts of the Red Sea), whereas it probably originated in the Indo-Malayan region. Arabia was just the ending point of the southern path of the Silk Road, by sea.
This mix of elements—a confusion between a place of origin and a market place, together with a therapeutic use identical from India to Greece—is probably typical of the many exchanges that took place along the Silk Road: whilst the products were carefully carried from one area to another, the knowledge of the uses of some may have resisted the entropic pressure to which they were exposed through the many miles of the road, and geographical knowledge may have been more easily lost as it referred to places that were not necessarily known and may have been just names; only the closest or the most known one was remembered.
Research on the transmission of knowledge about materia medica along the Silk Road will continue at the Institute. The database recording information on uses of plants and other natural products originating from the Far East or from any region on the Silk Road(s) will continue to be enriched with data collected from primary sources. On this basis, analysis will be pursued and will lead to a more complete image, with different phases through time and space. To be continued, thus ...
