of the sulphureous oyly and inflammable substance, then of the sa∣line which is the soonest dissoluble in water. They that come near this category or are in it, are Camphir, Mastick, Ladanum, Benjuin, Styrax, myrthe, and others which it would be needesse here to rehearse: we will then declare a method of the work that may be made upon the cheif and most usefull of them.
Gummes so properly called, are nothing else but concrete li∣quors easily dissolved in water or other waterish and moist men∣struums, as wine and vinegar: they are of 2. kinds: the first do consist of a volatile salt, predominant and somewhat sulphureous, and of a gummy viscous and clamy juice, proceeding from plants, shrubs and feculaceous trees, as Ammoniak, Galbanum, Opopanax, Euphorbium, Sagapenum, Assa faetida, and several others: the second are purely gummous and muscilagineous, proceeding also from some plants and fruit trees, as gum Arabick, gum of plum and cherry trees, and Tragacinth: these cannot suffer distillation, having none or litle of salt and sulphur in themselves.
The distillation of Ladanum.
THOUGH this gum be not much in use, yet it has many ex∣cellent proprieties, and I can say confidently, that it is but want of having made the anatomy of it, and of experience, that it has been so much neglected: for it is impossible that those that are better acquainted with it should not make use of it: it is a gum resin gathered upon the leaves of a shrub called Cistus Ledon; the best is that which is of a blackish green, easy to crumble, and yet as easily made into pills, working it between the fingers, inflam∣mable, and yeilding a sweet and pleasant smel in the burning. But there is this considerable in it, that though Ladanum be in∣flammable, yet will it not easily mix with oyles or other fat and unctuous substances: their use is that it abounds with volatile salt, and a portion of herbaceous extract which hinders its union and causes it to crumble: and this is a note of its principal vertue, because this sulphureous salt ascends in the distillation and is tur∣ned into an oyle, which is a specifick for many diseases; it is thus prepared.