Cinchona in quinology to examine the contents of these components in assays. The yields of quinine in the cultivated trees were low and it took a while to develop sustainable methods to extract bark. In the meantime Charles Ledger and his native assistant Manuel collected another species from Bolivia. Manuel was caught and beaten by Bolivian officials leading to his death but Ledger obtained seeds of high quality which were offered to the British who were uninterested, leading to the rest being sold to the Dutch. The Dutch saw its value and multiplied the stock. The species later named as "Cinchona
Therapeutice Specialis ad Febres Periodicas Perniciosas who first systematically studied the effect of cinchona in the treatment of malaria, wrote a book which he titled "Therapeutice Specialis ad Febres Periodicas Perniciosas". One highlight of the "Therapeutice Specialis" is the drawing "tree of fevers", where different fevers, such as branches of the tree, are divided into categories: on the left, those that respond to cinchona, are shown as branches covered with bark, while on the right are those for which cinchona is ineffective, and are depicted as denuded leafless branches. Torti clearly identified cinchona as a specific therapy for intermittent fevers, as opposed to continued fevers, which