Note 538 — BOOK XII. THE NATURAL HISTORY OF TREES.

This substance is still gathered from the Cistus creticus of Linnæus, which is supposed to be the same as the plant leda, mentioned by Pliny. It is also most probably the same as the Cisthon, mentioned by Pliny in B. xxiv. c. 48. It is very commonly found in Spain. The substance is gathered from off the leaves, not by the aid of goats, but with whips furnished with several thongs, with which the shrubs are beaten. There are two sorts of ladanum known in commerce; the one friable, and mixed with earthy substances, and known as “ladanum in tortis;” the other black, and soft to the fingers, the only adventitious substances in which are a little sand and a few hairs.