Ledger's cinchona seeds: a composite of field experience, chance, and intuition.

Following a short historical review of the facts which lead to the discovery of the specific action of the cinchona bark, an analysis is made of the obstacles encountered for more than two centuries by scientific expeditions to the identification, among the maze of natural hybrids, of the varieties of cinchona producing large amounts of quinine, and to obtain the best seed to establish plantations in other continents. Charles Ledger, a British general tradesman, was able to achieve that thanks to his alert spirit of observation, his (and that of his Bolivian servant Manuel) long experience of the Andes, and the chance that brought them to fall upon a group of exceptional cinchonas which had grown on an impervious slope of the Andes. Eventually the seeds were collected and Ledger offered them to the British and Dutch governments. Whereas the British failed to recognise their importance, the Dutch did not. They created extensive plantations in Java from which the world's demand for quinine was met, and the Dutch detained the practical monopoly of its production.