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PHEL

sulphuric acid, and applying heat, when a solution of perchloric acidis formed.

Perchloride of Cyanogen. This is obtained by filling a two pintbottle with very dry chlorine gas, putting in it gr. xv of anhydroushydrocyanic acid, and exposing it to the sun-beams, when theperchloride of cyanogen crystallizes on the sides of the glass.(Serullas.)

Perchlorocyanic Acid. The same as perchloride of cyanogen.

Peristaltic Persuaders. (Dr. Kitchener's.) See Pil. RheiCompos.

Permanent White. See Sulphas Barytje.

Perry. A liquor prepared from the expressed juice of pears, in a si-milar manner to that employed for making cider.

Persicaria. P. Arsesmart. Polygonum Persicaria. A native plant,which is astringent and stimulant, but is little used.

Periwinkle. See Vinca.

Peruvian Balsam. See Balsamum.

Peruvian Bark. See Cinchona.

Petroleum. L. P. Bitumen Petroleum. E. D. Barhadoes Tar, orMineral Tar. O. There are several species, such as naphtha,asphaltum, &c. ; all of which are stimulant, antispasmodic, andvermifuge, and externally irritant and discutient.Soluble in ether, and miscible with fixed and essential oils; but inso-luble in water and spirit of wine.Medicinally it is prescribed in doses of ti\x to 5ss for asthma, and fortapeworm ; and externally it is applied to affections of the joints,paralytic limbs, &c, by means of friction; but as it is rarely used,it can seldom be had at the shops.

Petroleum Sulphuratum. Barbadoes Balsam of Sulphur. Is pre-pared by mixing four parts of petroleum with one part of sulphur,and is applied to deterge foul ulcers, and as a stimulant.

Peucedanum Officinale. P. Sulphurwort. The root is reputed,but without good authority, to be diuretic, lactescent, and expec-torant.

Peucedanum Silaus. P. English Saxifrage. A native plant, whichis feebly aromatic, but is never used.

Peziza. P. A native fungus. Peziza auricula. Which is used as anastringent in form of gargle, in angina, and in form of lotion inophthalmia.

Piiellandrium Aquaticum. P. Water Hemlock. A native plant,but not very common, the seeds of which are aromatic, acrid, nar-cotic, and stimulant, and prescribed in doses of Jss to Jj of thepowder mixed with milk every morning, or in form of decoction