Such, then, is all that I have hitherto been enabled to learn or discover, worthy of mention, relative to plants. At the close of this subject, it seems to me that it will not be out of place to remind the reader, that the properties of plants vary according to their age. It is elaterium, as already stated,[1] that preserves its properties the longest of all. The black chamæleon[2] retains its virtues forty years, centaury not more than twelve, peucedanum[3] and aristolochia[4] six, and the wild vine one year—that is to say, if they are kept in the shade. I would remark, also, that beyond those animals which breed within the plants, there are none that attack the roots of any of those which have been mentioned by me; with the exception, indeed, of the sphondyle,[5] a kind of creeping insect,[6] which infests them all.