perineurial 4400 periorbital 
It [her religion! dwelt upon her spirit, and was incor- 
porated with the periodical work of every day. 
Jer. Taylor, Works, III. viii. 
(a) The smallest constant differenee~which, 2 - Of or pertaining to magazines, newspapers, 
added to the value of a variable, will leave that or other publications which appear or are pub- 
perineurium (per-i-uu'ri-um), n. ; pi. perineu- of a function (of which it is said to be the 1'shed at regularly recurring intervals. 
ria (-a). [NL., < Gr. m-pi, around, + veiipov, period) unchanged, (b) In vulgar arithmetic, In no preceding time, in our own or in any other coun- 
one of several similar sets of figures or terms, try ' nas anonymous periodical criticism ever acquired 
marked by points or commas pfaced regularly " early the 8ame Mcende %^ P Z? Eng Lit II 566 
after a certain number, as in numeration, in *>-_;,, < 
circulating decimals and in the extraction of ^^Sz^g^^o^a^^da^^ 
roots. Sometimes called degree. 11. In med., 
one of the phases or epochs which are distin- 
guishable in the course of a disease Archae- 
ological periods. See archaeological agex, under aye 
Calippic, Dionysian, Gaussian, hypothetical, Julian, 
lunisqlar period. See the adjectives. Latent period 
of a disease. Seelatent. Period of a wave. See tram. 
Period of incubation. Same as latent period of a dis- 
- . , ease. Sothiac period. Same as Sothiac cycle (which see, 
oculws, eye: see ocular.] Sur- under q/dei). Variable period, the period during which 
ing a nerve-fiber; of or pertaining to perineu- 9. The point or character that marks the end 
Hum. of a complete sentence, or indicates an abbre- 
perineuritis (per"i-nu-ri'tis), n. [NL., < peri- viation, etc.; afullstop, thus(.). 10. Inmti/l,.: 
nciiriitm + -itix.] Inflammation of the perineu- 
rium. 
nerve.] The membranous sheath surrounding 
a uerve-funieulus. Also called tieimlemma. 
perinium (pe-rin'i-um), n. [NL., < Gr. irepi, 
around, + if ('>'-), muscle, fibrous vessel in 
muscle, a vessel of plants.] In lot., a name 
proposed by Leitgeb for a peculiar outer layer 
that enters into the composition of the walls 
of the spores of certain Sepaiicx, such as Cor- 
Kiiiiti and SpJixrocarpim. it is frequently beautifully 
sculptured, and is derived from the membrane of the spe- 
cial mother-cells of the spores. 
periocular (per-i-ok'u-lar), a. [< Gr. nepi, 
around, + L. ' ' 
seventeen years in the northern United States, and thir- 
teen in the southern. See cut under Cicadids. Peri- 
odical diseases, diseases the symptoms of which recur 
treatment of subjects incident to writing or editing for 
periodical publications, is usually of less permanent and 
substantial interest than works on similar subjects pre- 
pared for publication in book form. 
II. n. A publication issued at regular inter- 
.. . 
oO, L.jfc*,<Gr. * t pU, a going round, a 
way round, circumference, a circuit, or a cycle 
of time, a regular prescribed course, a well- 
rounded sentence, a period, < Kepi, around, + 
<x!of, way.] 1. A circuit; around; hence, the 
time in which a circuit or revolution, as of a 
heavenly body, is made ; the shortest interval 
of time within which any phenomenon goes 
t 
', ] L 
Your honourable letter he desires 
To those have shut him up ; which failing, 
Periods his comfort Shak., T. of A., i. 1. 99. 
II. intrans. To end; cease. 
"Tis some poor comfort that this mortal scope 
Barton. 
as forming a book by itself. 
"'" periodicalist (pe-ri-od'i-kal-ist), . ^periodi- 
cal + -ist.] One who publishes, or one who 
writes for, a periodical. New Monthly Mag. 
periodically (pe-ri-od'i-kal-i), adv. At stated 
or regularly recurring intervals: as, a festival 
celebrated periodically. 
periodicalness (pe-ri-od'i-kal-nes), n. The 
.. (Wares.) state of being periodical; periodicity. [Bare.] 
through its changes to pass through them again periodic (pe-ri-od'ik), a. [< OP. periodic, F. pe- periodicity (pe"ri-o-dis'i-ti), n. [= F. periodi- 
immediately as before. riodique= Sp.periodico = T?g. It. periodico = D. cite = Pg. periodicidadc ; as periodic + -ity.~] 
periodiek(cf.Gr.periodisck = l)a,Ta.8vr.periodisk'), Periodic character; habitual tendency or dis- 
v Ij.periodicus, < Gr. mpuiutf. coming round at position to recur at stated intervals of time. 
The flowering, once determined, appears to be subject 
to a law of periodicity and habit. 
Whewell, Bridgewater Treatise, p. 22. 
Some experiments would be made how by art to make 
plants more lasting than their ordinary period. 
Bacon, Nat. Hist, certain times, periodic, < nepioSos, a going round, 
The rays of light differ from those of invisible heat only a period: see period.'] 1. Pertaining to or of 
in point of period, the former failing to affect the retina the nature of a period, cycle or round of years 
because their periods of recurrence are too slow. or events.- 2. Performed or proceeding in a Periodicity of an operation, in matt., the number of 
_ . ! 15 ' series of successive circuits or revolutions : as, tlm . e8 i t ha ? l ? b , e re Pf. ated ' ive <"* 
2. Any round of time, or series of years, days, the periodic motions of the planets round the P en aOntal (per"i-o-don'tal), a. [< Gr. mpi, 
etc. Speciflcally-(a) A revolution or series of years by sun, or of the moon round the earth 3 Han- around > + ol 'S (OOOVT-), = E. tooth, + -al.'] 
which time is measured; a cycle: as, the Calippic period; mm*fmnM*~ * t n ti. . :*: 11.. __i; ii_. 
the Dionysian period; the Julian period, (b) Any specified 
division of time : as, a period of a hundred years ; the pe- 
riod of a day. 
The particular periods into which the wholeperiod should . - =j ~> ^,^,.- 
be divided, in my opinion, are tRese: 1. From the fifteenth odic character of ague; the periodic motion of 
totheeudof the sixteenth century. 2. From thence to the a vibratino- tuniiio- fr,vV m- Tn,, i,,ol otti 
Pyreneau treaty. 3. From thence down to the present uug-ioik 01 musical string. 
tnne - Bolingbroke, Study of History, vi. Periodic gatherings for religious rites, or other pu 
3. An indefinite part of any continued state, 
existence, or series of events; an epoch: as, 
pening or occurring at regularly recurring in- Surrounding a tooth: specifically noting the 
tervals of time; statedly recurring: as a ne- . ? m f. bran e of the socket of a tooth. 
riodic publication; the periodic return of a Pen<>ntltis(per-i-o-don-trtis),. [NL.,<Gr. 
plant's flowering; periodic outbursts; the peri- ^Y"' a }' ' Mo6f (odovr-), = E. tooth, + -itis.] 
J 
(per-i-e si), n. pi. 
purposes, furnish opportunities for buying and selling 
which are habitually utilized. 
[NL., < Gr. jrcplotKoi, 
Greece, the name given by their Dorian cou- 
H. Spencer, Priu. of Sociol., 497. querors to the descendants of the original 
complete sentence; 
4.Jn^,: (?) Of orpertainingtoaperiodor ^SS^^f^^S^ 
^ te,np,e, .ay ^ff^^jg^ ^ur, ^ ^^^ -~in ^^^ ft + ^^r^ o^ V 
So spake the archangel Michael ;.then paused, til the end is reached -* Ct.oSphoritt8.-J Inflammation about the 
mi, ovary. 
to thrvexed q'uestion a^to t 8 rahfe'of ^^riooS^n- P er i?Phthalmic (per'-'i-of-thal'mik), a. [< Gr. 
tence or^entence^in which the meaning is suspended P 1 ' wound, + o^afycif, eye : see ophthalmic.] 
, 
As at the world's great period. Milton, P. L., xii. 467. 
A really good historian may . . . combine an earnest 
faith in the Unity of History with a power of creating 
most exact and minute reproductions of jteriods, scenes v . " """p^i'^*** ,, . ' -> r-*j ~j - "*-~ ^j.. .>,.. .^,,j 
and characters. Slubbs, Medieval and Modern Hist., p. 89! ^^ whicircouldT''"'^ "' heloose sente ce, orsen- SuiTOunding the eye; circumpcular ; orbital, 
4. The point of completion of a cycle of years 
or round or series of events; limit; end; con- 
clusion; termination. 
The period of thy tyranny approacheth 
Shak., 1 Hen. VI., iv. 2. 17. 
About foure of the clocke, they made a period of that 
solemnity. Coryat, Crudities, I. 39, sig. D. 
To end 
And give a timely period to our sports, 
Let us conclude them with declining night. 
B. Jonson, Cynthia's Revels, v. 3. 
Hence 5f. The end to be attained ; goal. 
This is the period of my ambition. 
Shak., M. W. of W., Hi. 3. 47. 
A. S. Hill, Rhetoric p. 152 
Milton is the last great writer in the old periodic style 
J. W. Hales, Int. to Milton's Areopagitica, p xxiiv.' 
Doubly periodic, having two periods. Doubly peri- 
odic functions, in math. See function. Periodic com- 
et. See comet, l. Periodic continued fraction. See 
continued fraction, under continued. Periodic curve 
fever, etc. See the nouns. Periodic function. Thia 
phrase is used in different senses in the calculus of func- 
tions and in the theory of functions. In the former a pe- 
riodic function is one whose operation being iterated a 
certain number of times restores the variable Thus 1 x 
is such a function, since 1 - (1 - x) = x. But in the theory 
of functions a periodic function is defined as a function 
having a period. For a more general definition, see/wnc- 

, n. [NL., 
.' eye>] A . genUS 
with the eyes approximated 
riHofhthalmusltartrtiiltri. 
on the upper surface of the head, very promi- 
fai 
Symposiu 
According to 1 the n'nmDer'oTcola it"contains"a'p'eriod1s ments are "rrangedin'ttie'order'oTtheir atomic'weMit&i'at ? ne Orbit , ? f , tne e 7 e : 8,8, Jieriopiic bones (those 
dicolic, tricolic, tetracolic, etc. The end (apothesis) of a feBi^'intervalsoftheserieswillbefoundelementswhich Dones which enter into the formation of the 
pe 1 ' must ^coincide with the end of a word, and is also J^ ve ?inlar chemical and physical properties that is, orbit). 
, around, + 
Surround- 
as Kna or verses. (See lines', (^^"g^up'rt^eriods'is si "!' in thelnd'ividual diff erenceVuMts members. ^erl- oral, pastoral, 'andi'nreoral ' 
Hied a system. Odic stars. See star. Periodic winds. See monsoon nprinrhita rupr i Av'W tii^ ',, r\rr e r 
pciiuiuiudi ^jjei-i-oi Di-ta^, n, LiNlj,, s trr. irept, 
t and f< periodic around ' + L - orbita, orbit: see orbit.'] The 
-., ...... . ^ neriod': nelt** periosteum of the orbit of the eye. 
brases; a 
end o 
osition, usually consisting of two or * i""""" IF<=-''-U I-KI;, . ar in. Aperiodic ^ e r. mi ' m ~* t , . ""ft. ": r t ,~ 
, T * i ~*" ~^'-J 1. (I* 1. -HaviiKj a period* Derformod L JC \ TOIC- 01 rue cyG, 
ed ; but it always involves a cadence at th ^ happpiiiiig at stated intervals; regularly or o)0tt(f, orbit: see <n'V(tfn.\ Of or 
eribd, by which it is distinctly separated from statedly recurring at the end of a fixed period P? lltam g to the orbit of the eye : as, p, rior- 
>. Usually a period includes eight or sixteen of time : as, periodical diseases ; periodical nub- , P al " Periorbital membrane, the lining mem- 
lications. J t r f " e of the olbit : the orhital periosteum, and its continu- 
;he period, by which i 
llows. Usuall 
leasures. 
