PARMELIA, a genus of lichens, with a leafy horizontal thallus which is lobed and cut; nail orbicular shields (apotheeia) fixed by a central point, concave, and bordered by the indexed thallus. The species are numerous, and many are found in Britain. Some of them are occasionally employed in dyeing. Various chemical principles have been dis covered in lichens of this genus, as Usnine or Ihnie acid (also found in species of the genus (Anea), and Parietim. Valuable medicinal properties—tonic and febrifugal—have been ascribed to Parmelia parietima, the common yellow wall lichen, or common yellow wall moss of the herb shops, a bright yellow species with deep orange shields, plentiful on walls and trees in Britain and most parts of Europe.
PARMENIDgS, a Greek philosopher of Elea, in lower Italy, and in the opinion of the ancients the greatest member of the Eleatic school, flourished • about the middle of the 5th C. B.C. Nothing is known with certainty regarding his life, but he is said to have visited Athens in his old age, and to have conversed with Socrates, then quite a youth. The story, though it rests on the authority of Plato, has a suspicious air, and seems as if it were intended to account for the influence which the philosophy of Parinenides undoubtedly exercised on that of Socrates and Plato themselves. Parmenides, like
Xenophanes of Colophon, sometimes regarded as the first of the Eleatics, expounded his philosophy in verse—Ids only work being a didactic poem On Nature. The leading design of this poem is to demonstrate the reality of absolute being, the non-existence of which Parmenides declares to be inconceivable, but the nature of which, on the other hand, he admits to be equally inconceivable, inasmuch as it is dissociated from every limitation under which man thinks. Parmenides is not a theologist in speculation, seek ing rather to identify his "Absolute Being" with "Thought" than with a "Deity." Only fragments of his poem remain, which have been separately edited by Ffilleborn (Zullichau, 1795); another collection is that by Brandis, in his Commentationes Eleaticm (Altona, 1815); but the best is to be found in Karsten's Plillosophorum GNECOPUM veterum lieliquire (Amstclod. 1835).