Part 190

2. An instrument for determining the extent and shape of the field of vision.

{ Per`i*met"ric (?), Per`i*met"ric*al (?), } a. Of or pertaining to the perimeter, or to perimetry; as, a perimetric chart of the eye.

Per*im"e*try (?), n. The art of using the perimeter; measurement of the field of vision.

Per"i*morph (?), n. [Pref. peri- + Gr. &?; form.] (Min.) A crystal of one species inclosing one of another species. See Endomorph.

Per`i*my"sial (?), a. (Anat.) (a) Surrounding a muscle or muscles. (b) Of or pertaining to the perimysium.

||Per`i*my"si*um (?), n. [NL., fr. Gr. &?; about + &?; muscle.] (Anat.) ||The connective tissue sheath which surrounds a muscle, and sends ||partitions inwards between the bundles of muscular fibers.

||Per`i*nÊ"um (?), n. See Perineum.

Per`i*ne"al (?), a. (Anat.) Of or pertaining to the perineum.

Per`i*ne"o*plas`ty (?), n. [Perineum + -plasty.] (Med.) The act or process of restoring an injured perineum.

Per`i*ne*or"rha*phy (?), n. [Perineum + Gr. &?; to sew.] (Med.) The operation of sewing up a ruptured perineum.

||Per`i*ne*phri"tis (?), n. [NL. See Peri-, and Nephritis.] (Med.) ||Inflammation of the cellular tissue around the kidney. -- ||Per`i*ne*phrit"ic, a.

||Per`i*ne"um (?), n. [NL., fr. Gr. &?;, &?;.] (Anat.) The region which ||is included within the outlet of the pelvis, and is traversed by the ||urinogenital canal and the rectum.

Per`i*neu"ri*al (?), a. (Anat.) Surrounding nerves or nerve fibers; of or pertaining to the perineurium.

||Per`i*neu"ri*um (?), n. [NL., fr. Gr. &?; about + &?; a nerve.] ||(Anat.) The connective tissue sheath which surrounds a bundle of ||nerve fibers. See Epineurium, and Neurilemma.

Per`i*nu"cle*ar (?), a. (Biol.) Of or pertaining to a nucleus; situated around a nucleus; as, the perinuclear protoplasm.

Pe"ri*od (?), n. [L. periodus, Gr. &?; a going round, a way round, a circumference, a period of time; &?; round, about + &?; a way: cf. F. pÈriode.] 1. A portion of time as limited and determined by some recurring phenomenon, as by the completion of a revolution of one of the heavenly bodies; a division of time, as a series of years, months, or days, in which something is completed, and ready to recommence and go on in the same order; as, the period of the sun, or the earth, or a comet.

2. Hence: A stated and recurring interval of time; more generally, an interval of time specified or left indefinite; a certain series of years, months, days, or the like; a time; a cycle; an age; an epoch; as, the period of the Roman republic.

How by art to make plants more lasting than their ordinary period.

Bacon.

3. (Geol.) One of the great divisions of geological time; as, the Tertiary period; the Glacial period. See the Chart of Geology.

4. The termination or completion of a revolution, cycle, series of events, single event, or act; hence, a limit; a bound; an end; a conclusion. Bacon.

So spake the archangel Michael; then paused, As at the world's great period.

Milton.

Evils which shall never end till eternity hath a period.

Jer. Taylor.

This is the period of my ambition.

Shak.

5. (Rhet.) A complete sentence, from one full stop to another; esp., a well-proportioned, harmonious sentence. "Devolved his rounded periods." Tennyson.